Article

The Great 2008 Chinese Ice Storm: Its Socioeconomic-Ecological Impact and Sustainability Lessons Learned

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Abstract

Extreme events often expose vulnerabilities of socioeconomic infrastructures and point to directions of much-needed policy change. Integrated impact assessment of such events can lead to finding of sustainability principles. Southern and central China has for decades been undergoing a breakneck pace of socioeconomic development. In early 2008, a massive ice storm struck this region, immobilizing millions of people. The storm was a consequence of sustained convergence between tropical maritime and continental polar air masses, caused by an anomalously stable atmospheric general circulation pattern in both low and high latitudes. Successive waves of freezing rain occurred during a month period, coating southern and central China with a layer of ice 50 to 160mm in thickness. We conducted an integrated impact assessment of this event to determine whether and how the context of socioeconomic and human-disturbed natural systems may affect the transition of natural events into human disasters. We found: 1) without contingency plans, advanced technologies dependent on interrelated energy supplies can create worse problems during extreme events, 2) the weakest link in disaster response lies between science and decision making, 3) biodiversity is a form of long-term insurance for sustainable forestry against extreme events, 4) sustainable extraction of non-timber goods and services is essential to risk planning for extreme events in forest resources use, 5) extreme events can cause food shortage directly by destroying crops and indirectly by disrupting food distribution channels, 6) concentrated economic development increases societal vulnerability to extreme events, and 7) formalized institutional mechanisms are needed to ensure that unexpected opportunities to learn lessons from weather disasters are not lost in distracting circumstances.

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... In the subtropics of China, natural broadleaved forests and natural mixed stands of conifers and broadleaved trees are typical vegetation types. Although ice storms could influence evergreen broadleaved forests, only recently, the importance of ice storms on forest development has been recognized (Zhou et al., 2011;Sun et al., 2012). ...
... A previous study showed that the sprouting regeneration ratio was associated with the damage degree (Masaka et al., 2000;Del Tredici, 2001). A rare opportunity to assess branch resprouting ability and its dynamics was made by a heavy ice storm that occurred in early 2008 in China (Zhou et al., 2011;Wang et al., 2016). The ice storm hit southern and central China, a primary region of China's terrestrial carbon storage, from 10 January to 6 February 2008 (Zhou et al., 2011). ...
... A rare opportunity to assess branch resprouting ability and its dynamics was made by a heavy ice storm that occurred in early 2008 in China (Zhou et al., 2011;Wang et al., 2016). The ice storm hit southern and central China, a primary region of China's terrestrial carbon storage, from 10 January to 6 February 2008 (Zhou et al., 2011). In these studies, the types of damage to trees were classified into crown decapitated, stem broken, branch broken, bending, and uprooted. ...
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Introduction Natural disturbances modify forest structure by affecting regeneration dynamics and can change main ecosystem functions. An ice storm unusually took place in southern China in early 2008, which caused huge damage to forests. Resprouting of woody plants in a subtropical forest has received little attention. The role of survival time and mortality has been assessed for newsprouts after an ice storm. Methods In this study, damage types, in addition to the annual number and mortality rates of sprouts for all tagged and sampled resprouted Chinese gugertree (Schima superba Gardner & Champ.) individuals more than or equal to 4 cm in basal diameter (BD), were monitored. A total of six plots (20 m × 20 m) wererecorded in a subtropical secondary forest dominated by S. superba in Jianglang Mountain, China. This investigation had been conducted for six consecutive years. Results The results showed that the survival rates of the sprouts were dependent on the year they sprouted. The earlier the year they boomed, the lower the mortality. The sprouts produced in 2008 were of the highest vitality and survival rates. Sprouts of the decapitated trees exhibited a better survival rate than those of uprooted or leaning trees. Sprouting position also plays a role in regeneration. Sprouts at the basal trunks of uprooted trees and the sprouts at the upper trunksof the decapitated trees exhibited the lowest mortality. The relationship between the accumulative mortality rate and the average diameter of new sprouts isaffected by damage types. Discussion We reported the mortality dynamics of sproutsin a subtropical forest after a rare natural disaster. This information could serve asa reference for the construction of a branch sprout dynamic model ormanagement of forest restoration after ice storms.
... As a transition zone between tropical and subtropical regions, South China is a major area of winter precipitation (Ke et al., 2019;Zhang et al., 2015). South China winter precipitation (SCWP) exhibits prominent interannual variability and often leads to extreme weather events such as snowstorms and freezing rain, which impact agriculture, traffic and energy et al. (Yuan et al., 2014;Zhang et al., 2009;Zhou et al., 2011). For example, in 2005, the extreme freezing rain and snow in South China disrupted traffic, damaged forest ecosystems, and resulted in considerable losses of life and property (Chen & Sun, 2010;Wen et al., 2009;Wu et al., 2011;Zhou et al., 2011). ...
... South China winter precipitation (SCWP) exhibits prominent interannual variability and often leads to extreme weather events such as snowstorms and freezing rain, which impact agriculture, traffic and energy et al. (Yuan et al., 2014;Zhang et al., 2009;Zhou et al., 2011). For example, in 2005, the extreme freezing rain and snow in South China disrupted traffic, damaged forest ecosystems, and resulted in considerable losses of life and property (Chen & Sun, 2010;Wen et al., 2009;Wu et al., 2011;Zhou et al., 2011). As such, a better understanding of SCWP is of great scientific and socioeconomic importance. ...
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As the dominant mode of low‐frequency atmospheric variability in extratropical Northern Hemisphere, the Arctic Oscillation (AO) exerts strong impacts on East Asian climate, with the positive AO leading to increased South China winter precipitation (SCWP). Here, we find that such AO–SCWP relationship is nonstationary and controlled by the remote Atlantic Multidecadal Oscillation (AMO). Especially, the relationship between positive AO and SCWP is significantly weakened during the warm phase of AMO. Observational analyses and idealized Atlantic pacemaker simulations indicate that warm AMO forcing is accompanied by a teleconnection wave train extending eastward from the North Atlantic to West Pacific and the western North Pacific sea surface temperature warming, which together induce northerly wind anomalies over South China by enhancing the land–ocean pressure gradient. Such climate background state changes associated with the warm AMO prohibit the positive AO induced water vapor transport to South China, thereby weakening the AO–SCWP relationship.
... During the cold wave outbreak, the abrupt decrease in temperature raises the risk of cardiovascular diseases and relative mortality (McGeehin and Mirabelli 2001;Shi et al. 2015;Ballester et al. 2016;Wang et al. 2016). In addition, the sustained low-temperature condition may aggravate the burdens of traffic and energy supply (Zhou et al. 2011;Kim and Lee 2019) and reduce agricultural production (Wheeler et al. 2000;Liu et al. 2006;Lobell et al. 2011). Moreover, under appropriate moisture conditions, cold waves may also bring snowstorms or freezing rain, leading to catastrophic effects on human society, like the persistent freezing rain in southern China in January 2008 (Hong and Li 2009;Zhou et al. 2011). ...
... In addition, the sustained low-temperature condition may aggravate the burdens of traffic and energy supply (Zhou et al. 2011;Kim and Lee 2019) and reduce agricultural production (Wheeler et al. 2000;Liu et al. 2006;Lobell et al. 2011). Moreover, under appropriate moisture conditions, cold waves may also bring snowstorms or freezing rain, leading to catastrophic effects on human society, like the persistent freezing rain in southern China in January 2008 (Hong and Li 2009;Zhou et al. 2011). ...
Article
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Synoptic temperature variability gives rise to cold waves and extreme cold events in winter. Based on four reanalysis datasets, this study investigates the decadal trend of synoptic temperature variability in boreal winter during the period from 1980 to 2019, with particular focus on the sharp drops in synoptic-scale temperature, which are associated with cold waves. The result shows that the synoptic-scale standard deviation of temperature decreases significantly with a trend of − 0.15 K/decade (− 0.09 to − 0.21 K/decade among reanalysis datasets) over continental regions in mid-high latitudes. Correspondingly, the rapid cooling events (RCEs), defined based on the day-to-day temperature decrease exceeding 6 K, also show a general decreasing trend in terms of their frequency and intensity. The strongest decrease occurs over eastern North America (ENA) and western Eurasia (WE). The weakening of the RCEs is closely connected to the decreased trend of eddy kinetic energy (EKE), suggesting that the weakened transient eddy activities may have mitigated the synoptic-scale temperature variability and the associated RCEs over mid-high latitudes. This study highlights that the decreased synoptic temperature variability leads to fewer and weaker RCEs on the synoptic scale over mid-high latitudes in winter though the mean state of winter temperature continues to warm.
... DKL demonstrated significantly better performance than the Ramer Scheme across these metrics, particularly in terms of accuracy and precision. We selected the years 2008, 2011, and 2018, when severe FR occurred widely 5,53,55 , and collected damage reports data from CMA, Ministry of Emergency Management of the People's Republic of China, and China Electricity Council (CEC) to verify if DKL outperformed the Ramer Scheme. Generally, the main difference between DKL and the Ramer Scheme is that the Ramer Scheme classified more FR events in the Northern, Northwestern, Northeastern, and Southwestern regions (Fig. 5). ...
Article
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Freezing rain (FR) event is a highly catastrophic event, significantly impact human habitats. However, there is still a substantial lack of gridded FR data. Here, we present a comprehensive gridded FR dataset across China from January 1, 2000, to December 31, 2019, utilizing station data from the China Meteorological Administration combined with ERA5-land and pressure level data. Employing Deep Kernel Learning (DKL), we effectively classified and predicted FR occurrences, demonstrating significant advancements in capturing complex atmospheric conditions conducive to FR. The DKL model, validated against ERA5 data for the winter of 2024 and the Ramer Scheme in 2008, 2011, and 2018, showcases superior classified power over traditional methods, achieving remarkable accuracy of 0.991, Area Under the Curve (AUC) of 0.999, recall of 0.973, and precision of 0.989. The implications of this research are profound, offering a robust database for academic and practical applications in weather forecasting, climate modelling, and disaster management, thereby enhancing our understanding and mitigation strategies for FR impacts.
... • The Great 2008 Chinese Ice Storm occurred in the southern region of China, causing widespread power system failure, which triggered the disruption of water supply, railway system, medical service system, and supply chains, with direct economic losses of up to 156 billion yuan. Millions of people suffered from these large-scale disruptions; for instance, the disruption of the railway system coincided with the peak of the Spring Festival (high travel demand), and about 5. 8 million people were stranded in railway stations alone, unable to return home [9]; the disruption of the supply chains led to the shortages of food and escalation of food price in 11 provinces [12]. ...
... These WECEs often cover multiple countries, even with continental extension. WECEs in East Asia have become more intense and frequent since the beginning of the twentyfirst century ), a series of extreme cold events occurred in East Asia during the winters of 2007/08 Zhou et al. 2011;Kuang et al. 2019), 2015/16 (Dai and Mu 2020 and 2020/2021 (Dai et al. 2022;Zhang et al. 2022a, b), and the increased frequency of extreme cold events has been linked to global warming (Kuang et al. 2019). ...
Article
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Extreme cold events have a great impact on environment and human health. The occurrence of winter extreme cold events (WECEs) in the Northern Hemisphere is usually modulated by circulations over different specific regions. However, how to detect and quantify the effects of these coupled circulations over different regions on WECEs is still unclear. In this study, the dynamic system method is extended with lags to investigate the modulation of coupled Ural (UR) and Okhotsk (OK) circulation fields on WECEs over East Asia. Taking the dynamical lead-lag relationship into account of the interaction between the circulations over these two regions, contributions of the modulation of coupled Ural (UR) and Okhotsk (OK) circulation fields to WECEs over East Asia are mainly classified into two distinct categories. When the circulation fields over OK dynamically lag behind those over UR, WECEs are mainly controlled by Ural blocking and polar vortex splitting. The development and decay of the upstream Ural Ridge promote the movement of the downstream trough to lead to the circulation turning meridional-oriented, together with the polar vortex from strong to weak and splitting southwards. Then cold air is guided to move southwards to form winter cold events over a larger domain beyond East Asia. Whereas, when the circulation fields over UR dynamically lag behind those over OK, there exist North and South branches of the circulation, with the North one mainly controlled by UR and OK blockings and the South one mainly controlled by a cyclone over the sea surface. Two blockings move towards each other and create a larger blocking which results in enhanced meridional flow, cyclone moves eastwards by transporting water vapor to a cool surface and forms weaker winter cold events over a confined domain within East Asia.
... Furthermore, P. elliottii is typically characterized by dense foliage and large lateral branches during its juvenile phase, contributing to the severe damage during the 2008 snow disaster in southern China. Therefore, hybridization to improve the needle size and lateral branch traits holds significant potential for enhancing its resilience to such events [9,10]. ...
Article
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This study aimed to compare and assess the genetic diversity and trends among the introduced family provenance, first-cycle superior trees breeding provenance, and improved-generation superior trees breeding provenance of Pinus elliottii using EST-SSR markers. The goal was to provide a foundation for advanced genetic improvement and sustainable utilization of P. elliottii in Jiangxi Province. A total of 417 individuals were analyzed for their genetic diversity and population structure using 19 pairs of SSR markers. The analysis identified 103 alleles across all the samples, with an average of 5.421 alleles per locus. Compared to other coniferous species, P. elliottii exhibited a moderate to high level of genetic diversity (I = 0.862, He = 0.457). Analysis of the molecular variance (AMOVA) revealed that 97.90% of the genetic variation occurred within provenances, consistent with a low genetic differentiation coefficient (Fst = 0.016 < 0.05) and high gene flow (Nm = 15.715) among provenances. In addition, analysis using STRUCTURE v. 2.3.4 software divided the 417 germplasm samples into two distinct groups, corroborating the results of the principal coordinates analysis (PCoA) and the unweighted pair group method with arithmetic (UPGMA) clustering analysis. Overall, the germplasm resources of P. elliottii exhibited rich genetic diversity, with the majority of the genetic variation occurring within provenances. For the genetic improvement of high-resin-yielding slash pines, breeding programs should prioritize populations with high genetic diversity while carefully selecting superior individuals from within those populations. These findings provide a solid foundation for breeding high-resin-yielding varieties and for future research on the sustainable utilization of these valuable resources.
... It made a significant contribution to the most complex winter weather conditions during the Lunar New Year travel rush in China since 2008 71 . As a reference to the great 2008 Chinese ice storm 72 , users can use the graphical tool to visualize the AR development from 24 January to 2 February (e.g. Fig. 7). ...
Article
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Atmospheric Rivers (ARs) are long and narrow bands of strong horizontal water vapour transport concentrated in the lower troposphere. ARs play an important role in producing some high-impact weather events such as extreme precipitation and flooding, damaging winds, and temperature anomalies. To facilitate various studies on the short- and long-term variability of ARs and their impacts, I compiled a multi-decade global dataset containing 12 relevant meteorological variables for AR analysis. These variables were derived from the European Centre for Medium-Range Weather Forecasts atmospheric reanalysis version 5 (ERA5). They are available at 6-hour intervals from 1940 to present. Also included in the dataset is an interactive web browser-based graphical tool for visualising the AR evolution on regional (North America) and global scales. This ERA5-based Dataset for Atmospheric River Analysis (EDARA) may serve as a valuable resource for many AR-related research and applications.
... This caused a damaging period of extreme cold over southern China. Over 100 million people were affected, and the direct economic losses were estimated to be RMB 152 billion RMB (Ding et al., 2008;Li et al., 2009;Qian & Fu, 2010;Sun & Zhao, 2010;Tao et al., 2008;Zhao et al., 2019;Zhou et al., 2011). Consequently, an understanding of the variability of the Kunming quasi-stationary front is of great scientific and practical importance. ...
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Using ERA5 reanalysis data, this study explores the interannual variability of the occurrence frequency of the stronger Kunming quasi‐stationary front during in winter over the period 1980–2021 and the main causes of the variability. The results indicate that the occurrence frequency is significantly modulated on interannual timescales by southwesterly anomalies over the warmer region west of 103° E and northeasterly anomalies over the colder region east of 106° E. When the stronger southwesterly anomalies over the warmer region are comparable with stronger northeasterly anomalies over the colder region, the inhomogeneities of horizontal convergence and diabatic heating are strengthened near the frontal zone. This anomalous circulation causes a higher‐than‐normal occurrence frequency of the stronger Kunming quasi‐stationary front in winter. The East Asian winter monsoon (EAWM) and circumglobal teleconnection (CGT) are the two most important controls on the interannual variability of the occurrence frequency of the stronger Kunming quasi‐stationary front. Both the CGT and EAWM modulate the inhomogeneities of horizontal convergence and diabatic heating on the west flank of the front, and the EAWM further regulates diabatic heating over the east flank of the front.
... Cold surges often occur in the mid-latitudes of the Northern Hemisphere (e.g., China, North America), and have enormous effects on socioeconomic development, causing substan-tial economic losses and casualties (Wi et al., 2011;Ryti et al., 2016;Lewis and King, 2017;Chen et al., 2020). A massive ice storm caused by a strong CS affected China in 2008, causing direct economic losses of more than $22.3 billion and resulting in 129 deaths (Zhou et al., 2011). In 2020, a record-breaking CS in China greatly impacted transport and agricultural production and resulted in economic losses (Dai et al., 2022). ...
Article
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Cold surges (CSs) often occur in the mid-latitude regions of the Northern Hemisphere and have enormous effects on socioeconomic development. We report that the occurrences of CSs and persistent CSs (PCSs) have rebounded since the 1990s, but the trends related to the frequencies of strong CSs (SCSs) and extreme CSs (ECSs) changed from increasing to decreasing after 2000. The highest-ranked model ensemble approach was used to project the occurrences of various CSs under the SSP1-2.6, SSP2-4.5, and SSP5-8.5 scenarios. The frequencies of the total CSs show overall decreasing trends. However, under the SSP1-2.6 scenario, slight increasing trends are noted for SCSs and ECSs in China. Atmospheric circulations that are characterized by an anomalous anticyclonic circulation with a significantly positive 500-hPa geopotential height (Z500) anomaly at high latitudes along with significant negative anomalies in China were favorable for cold air intrusions into China. In addition, the frequencies of all CS types under the SPP5-8.5 scenario greatly decreased in the long term (2071–2100), a finding which is thought to be related to negative SST anomalies in the central and western North Pacific, differences in sea level pressure (SLP) between high- and mid-latitude regions, and a weaker East Asian trough. In terms of ECSs, the decreasing trends observed during the historical period were maintained until 2024 under the SSP1-2.6 scenario. Compared to the SSP1-2.6 scenario, the Z500 pattern showed a trend of strengthened ridges over the Ural region and northern East Asia and weakened troughs over Siberia (60°–90°E) under the SSP2-4.5 and SSP5-8.5 scenarios, contributing to the shift to increasing trends of ECSs after 2014.
... Near-surface temperature prediction has numerous implications for everyday life, from planning outdoor activities to taking measures to protect crops and livestock. In particular, daily maximum and minimum temperatures (T max and T min ) are often used to derive other climatic parameters such as growing-season length, heating and cooling degree-days, and the variability of annual temperature cycle (Brinkmann least 129 deaths and an economic loss of billions of dollars; it is considered the worst winter weather event in more than half a century (Zhou et al. 2011;Zhang and Zhi 2015). Therefore, there is a mandatory requirement to improve the forecast accuracy of near-surface temperatures for disaster prevention and mitigation (Kautz et al. 2020;Zhang et al. 2021;Lin et al. 2022;Mo et al. 2022). ...
Article
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Predictions of daily maximum and minimum temperatures (Tmax and Tmin) are key components of operational weather forecasting. Here we show how a deep learning scheme can be used to improve their predictions based on the numerical weather prediction (NWP) output from the European Centre for Medium-Range Weather Forecasts − Integrated Forecasting System (ECMWF-IFS). Using an optimal factor set screened by a regression method, an error-correction model for Tmax and Tmin forecasts based on the Spatio-Temporal Stacked Residual Network (STS-ResNet) is established. We find that errors in Tmax and Tmin forecasts for Hunan Province, China, can be reduced by approximately 21% and 33% respectively. However, although the Tmax and Tmin forecasts at almost all terrain elevations have been improved, the improvement decreases with the increasing terrain elevation. To solve this problem, we designed the Residual and Spatial Attention STS-ResNet (SASTS-ResNet) based on spatial attention mechanism. In mountainous regions, the SASTS-ResNet makes up for the deficiency of STS-ResNet in improving the Tmax forecasts of the ECMWF-IFS (with the improvement increasing from 1.45 to 42.53%), which has also largely improved the Tmin forecasts (from 27 to 83%). Moreover, the ECMWF-IFS model, STS-ResNet and SASTS-ResNet all have some uncertainties in Tmax and Tmin in high-elevation areas, where the smallest uncertainty is found in the SASTS-ResNet model.
... In addition to the cold, the associated phenomena such as strong winds, heavy snowfall and freezing precipitation significantly heighten risks to transportation and electricity delivery systems (Changnon & Changnon, 2006;Chen et al., 2019bChen et al., , 2021. A poignant example of these impacts is the 2008 cold event in south China, which resulted in over U.S. $20 billion in direct economic losses and 129 fatalities (Zhou et al., 2011). Given the increasing frequency and intensity of extreme weather events in numerous regions, a consequence of ongoing global warming (Arial et al., 2021), understanding the characteristics of cold weather events is crucial for guiding societal adaptation and mitigating impacts. ...
Article
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This study investigates the characteristics of cold events affecting eastern China during November–March of 1979–2018 using station observations and the ERA5 reanalysis, focusing five major cities (Beijing, Zhengzhou, Wuhan, Shanghai and Guangzhou) for their high vulnerability and distinct local thermal conditions than the broader climate regimes. For each city, cold day (CD) (one or more continuous days where the temperature falls below the local 5th percentiles) and cold surge (CS) (a period of 1–3 days with a total temperature decrease exceeding 8°C) were both examined in aspects of occurrence frequency, circulation characteristics and health impacts. Results show that the northern cities are relatively more/less exposed to CD/CS than the southern cities. At all five cities, the two types of events rarely coincide and exhibit distinct multiple‐year variations, as CD and CS are, respectively, dominated by continental‐ and regional‐scale circulations. However, both types of events are associated with the interplay of the East Asia trough at 300 hPa and the Siberian high, Aleutian low and subtropical high at 850 hPa. Results also show that during CDs in these cities, the effective temperatures (ET), which take into account of the near‐surface wind speed and humidity, are often about 5°C lower than the actual temperatures. The ET decreases are larger than the actual temperature drops in most CSs, yet in specific scenarios (primarily in Beijing and Zhengzhou when the temperature drop is relatively small), the ET drop can be less pronounced, as the possible decrease of wind speed and/or humidity can partially mitigate the ET decrease caused by dropping temperatures. These underline the complexity of health impacts of cold events, which vary regionally due to differences in covariations of temperature, wind speed and relative humidity. There aspects are worthy of further investigation.
... • The Great 2008 Chinese Ice Storm occurred in the southern region of China, causing widespread power system failure, which triggered the disruption of water supply, railway system, medical service system, and supply chains, with direct economic losses of up to 156 billion yuan. Millions of people suffered from these large-scale disruptions, for instance, the disruption of the railway system was coincided with the peak of the Spring Festival (high travel demand), and about 5. 8 million people were stranded in railway stations alone, unable to return home [9]; the disruption of the supply chains led to the shortages of food and escalation of food price in 11 provinces [12]. ...
Preprint
Infrastructure systems play a critical role in providing essential products and services for the functioning of modern society; however, they are vulnerable to disasters and their service disruptions can cause severe societal impacts. To protect infrastructure from disasters and reduce potential impacts, great achievements have been made in modeling interdependent infrastructure systems in past decades. In recent years, scholars have gradually shifted their research focus to understanding and modeling societal impacts of disruptions considering the fact that infrastructure systems are critical because of their role in societal functioning, especially under situations of modern societies. Exploring how infrastructure disruptions impair society to enhance resilient city has become a key field of study. By comprehensively reviewing relevant studies, this paper demonstrated the definition and types of societal impact of infrastructure disruptions, and summarized the modeling approaches into four types: extended infrastructure modeling approaches, empirical approaches, agent-based approaches, and big data-driven approaches. For each approach, this paper organized relevant literature in terms of modeling ideas, advantages, and disadvantages. Furthermore, the four approaches were compared according to several criteria, including the input data, types of societal impact, and application scope. Finally, this paper illustrated the challenges and future research directions in the field.
... Ice accretion from freezing rain can damage power and communication lines, housing, and other infrastructure; disrupt and endanger air and ground transportation Houston and Changnon 2007); and harm plants and animals (Millward and Kraft 2004;Zhou et al. 2011). In the Northern Hemisphere, freezing rain is most common in eastern Russia, central Europe, Fennoscandia, Canada, and parts of the United States (Carrière et al. 2000;Cortinas et al. 2004;Groisman et al. 2016). ...
Article
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Topographically channeled winds such as gap winds can be key drivers of freezing rain and ice accretion. Understanding the effect of these winds on the response of freezing rain and ice accretion to global warming is challenging because the spatial resolution of global, and most regional, climate models is too coarse to accurately simulate these winds. To examine the effect of global warming in a region influenced by strong gap winds (the northern Willamette Basin, Oregon, United States), we used 13 year retrospective and pseudo-global warming simulations from a high-resolution, convection-permitting climate model capable of reproducing the easterly gap winds through the Columbia River Gorge. We compared results from the high-resolution model to those from a large ensemble of simulations generated with a coarser-resolution climate model without a well-defined Gorge. Generally, the future projected occurrence of freezing rain decreased at lower elevations and increased at higher elevations. Easterly, low-level winds that bring cold air into the basin were stronger during projected future freezing rain because in a warmer climate, weaker easterly winds were less likely to decrease the basin’s near-surface air temperatures to sub-freezing. Because of the stronger gap winds, more of the projected ice events had longer durations and accreted more ice, even at low elevations downwind of the Gorge. The coarser resolution model also projected stronger easterly winds during freezing rain, which implies that the necessity for stronger easterly winds during future freezing rain is not limited to the gap winds but is a regional, if not more widespread.
... However, extreme heavy snowfall has the potential to cause disastrous effects on transportation, energy supply, and people's lives. For instance, a severe snowstorm over south China in early 2008 affected more than 100 million people and led to a direct economic loss of over 20 billion dollars (Zhou et al. 2011). Therefore, an advanced understanding of the variability of snowfall and its underlying mechanisms is of great importance for both the natural environment and human society. ...
Article
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This study investigates the dominant modes of the interannual variability of the northern Eurasian winter snowfall during 1982–2020 and explores their potential influencing factors and the associated physical processes. The first and second empirical orthogonal function (EOF) modes feature coherent snowfall anomalies over the high latitudes of Eurasia and western Siberia, respectively. Further analyses indicate that the anomalous atmospheric circulations play a major role in forming the snowfall variability, which could be further attributed to the influences of the atmospheric teleconnection patterns and Arctic sea ice variations. Specifically, the anomalous circulations related to the first EOF mode are mainly contributed by the effects of the teleconnections of the Polar–Eurasian and Scandinavian patterns. The formation of the second EOF mode has a close connection with the North Atlantic Oscillation and the Eurasian pattern. In addition, the sea ice variations over Baffin Bay exert a considerable influence on the snowfall anomalies related to the second EOF mode by exciting a wave train–like anomalous circulation. This effect is further verified by a numerical simulation. An empirical statistical model based on the above influencing factors can well explain the temporal evolutions of the two dominant modes, verifying the important value of our results to improve the understanding of interannual variability of northern Eurasian winter snowfall.
... Southern China is a climate-sensitive region of China, which is vulnerable to extreme climate events due to the rapid development of the economy and high population density. The precipitation-related extreme events over southern China in winter have caused great socioeconomic losses (Zhou et al 2011). In February 2022, a compound cold-wet event occurred in southern China (hereafter referred to as CWESC). ...
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A severe compound cold-wet event occurred in southern China (hereafter referred to as CWESC) in February 2022, leading to enormous socioeconomic losses. In this study, we proposed a new index to denote the severity of the compound cold-wet event. Based on the multivariate survival method, the CWESC in February 2022 is identified as the severest event during the past six decades. Our results indicate that the CWESC in 2022 is jointly regulated by the La Niña-like SST condition in the tropical Pacific and the warm SST anomalies in the North Atlantic, and a teleconnection in the Northern Hemisphere during winter (hereafter referred to as TNHW) plays the key role. The TNHW pattern originates from the tropical Pacific, and it splits into two routes over the North Atlantic. The northern branch of TNHW propagates via the Arctic and Siberia, causing intensified near-surface northerly wind and partially inducing an anomalous anticyclone over the western North Pacific (WNP). The southern branch of TNHW propagates via the Mediterranean and western Asia, inducing a deepened India–Burma trough and partially inducing the anomalous anticyclone over WNP. The intensified near-surface northerly wind causes enhanced cold advection over southern China, while the deepened India–Burma trough and the anomalous anticyclone over WNP cause increased southerly warm and moist air flow towards southern China, resulting in the CWESC in 2022. Moreover, four groups of numerical experiments forced by tropical Pacific, North Pacific, and North Atlantic SST anomalies are conducted based on the Community Atmosphere Model version 5. The results confirm the important roles of the La Niña-like condition and the warm SST anomalies in the North Atlantic in causing the CWESC in 2022.
... The rising concern over extreme weather and climate events, including extreme snowfall, is driven by their potential serious socioeconomic impacts in the context of global warming (Zhou et al., 2011;Nicolet et al., 2016;Wang et al., 2016;Tei et al., 2020). Over recent decades, extreme snowfall events have exhibited a noticeable upward trend in northern China, occurring on both interannual and interdecadal timescales (Zhao et al., 2016;Zhou et al., 2018Zhou et al., , 2021. ...
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In recent decades, Northeast China (NEC) has witnessed a substantial 20% rise in the occurrence of intense winter snowfall, resulting in a notable increase in the overall snowfall accumulation. Using Empirical Orthogonal Function (EOF) analysis, this study identifies a dominant interdecadal variation of the winter extreme snowfall with a turning point around 2000. The analysis uncovers abnormal atmospheric circulations linked to the positive phase of the like-Scandinavian pattern and anomalous North Pacific anticyclone, providing favorable conditions for cold air outbreak and water vapor enhancement for the increase in extreme snowfall. The positive phase of the like-Scandinavian pattern exhibits a strong correlation with sea ice loss in the Baffin Bay, Greenland Sea, and Barents-Kara Sea (BGBK). This positive pattern is primarily sustained by a positive feedback mechanism stemming from sea-ice-atmosphere interactions. Specifically, the positive like-Scandinavian pattern leads to increased water vapor over the BGBK region, promoting sea ice loss through enhanced clear-sky downward longwave radiation (CDLW) and increased surface turbulent heat flux. Conversely, a positive sea surface temperature anomaly prevails in the negative phase of the Interdecadal Pacific Oscillation (IPO), triggering an anomalous anticyclone over the North Pacific and East Asia, contributing to the observed increase in extreme snowfall over NEC. Furthermore, this study demonstrates a modulating relationship between the positive like-Scandinavian pattern and the anomalous anticyclone associated with the negative phase of the IPO, achieved through the triggering of Rossby wave trains, which were verified through numerical experiments using a atmospheric general circulation model. These results underscore the joint impact of interdecadal variability in Arctic Sea ice and the IPO on the decadal increase in winter extreme snowfall over NEC.
... In contrast, winter precipitation accounts for a small proportion of the total and is usually not a cause for concern (Ge et al. 2016). However, it can still cause severe disasters (Zhou et al. 2011;Xie et al. 2014). For instance, freezing and snow disasters in 2008 resulted in a large number of casualties in South China (Ding et al. 2008;Xie et al. 2014). ...
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... However, the impact varies significantly across the globe. For example, in early 2008, a severe snowfall event occurred in southern China, which led to more than 100 million people being affected and direct economic losses above USD 20 billion [8]. A severe snowstorm from December 2009 to January 2010 invaded the city of Altai in northern Xinjiang and led to record-breaking snowfall (from the last 60 years of observations), and wreaked havoc on livestock, agriculture, and local populations [9]. ...
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This chapter aims to introduce the impact of the 2008 ice storm on forest trees and ecosystem functions in southeast China. The ice storm damaged forests of 20 million hectares, about 10% of the total forestland in China, and caused significant ecological disturbance and damage to the forest ecosystem. There are different damage patterns in natural and plantation forests, with general patterns including uprooting, stem breakage, bending, and leaning. However, there were some differences among the tree species. The severity of forest tree species damage was classified as severe, moderate, or light based on standing volume loss or tree number loss. The chapter also discusses the storm-caused damage to forest ecosystems, which considerably changes the structure and function of the ecosystems. The damage to the ecosystem structure has weakened the capacities for water and soil conservation, water resource management, and has resulted in reduced biodiversity. It is essential to evaluate the impact of massive ice storms on major forest types in southeast China, which will serve as valuable references in tree plantation and forest management in the future.
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Winter precipitation anomalies in South China (SC) frequently result in severe disasters. However, the evaluation of prediction performance and distinctions between positive precipitation anomaly events (PPA, wet condition) and negative precipitation anomaly events (NPA, dry condition) in current operational models remains incomplete. This study employed the Climate Forecast System version 2 (CFSv2) to assess winter precipitation prediction accuracy in SC from 1983 to 2021. Differences in predicting PPA and NPA events and the underlying physical mechanisms were explored. The results indicate that CFSv2 can effectively predict interannual variations in winter precipitation in SC, as there is a significant time correlation coefficient of 0.68 (0.62) between observations and predictions, with a lead time of 0 (3) months. The model revealed an intriguing asymmetry in prediction skills: PPA outperformed NPA in both deterministic and probabilistic prediction. The higher predictability of PPA, as indicated by the perfect model correlation and signal-to-noise ratio, contributed to its superior prediction performance when compared to NPA. Physically, tropical signals from the ENSO and extratropical signals from the Arctic Sea ice anomaly, were found to play pivotal roles in this asymmetric feature. ENSO significantly impacts PPA events, whereas NPA events are influenced by a complex interplay of factors involving ENSO and Arctic Sea ice, leading to low NPA predictability. The capability of the model to replicate Arctic Sea ice signals is limited, but it successfully predicts ENSO signals and reproduces their related circulation responses. This study highlights the asymmetrical features of precipitation prediction, aiding in prediction models improvement.
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Hunan Province is one of the regions that are mostly affected by the freezing rain and ice disaster in China, because its unique topography is conducive to the southward intrusion of cold air from the north. This hazard can cause the line icing, threaten the operation of power grid and bring great socioeconomic losses. Understanding the mechanisms related to the topography effect on precipitation near Hunan is important to improve the prediction and prevention for the ice disaster during winter. In this study, we focus on an icing event at the beginning of 2022. The frontal precipitation in central Hunan features a southwest-northeast band distribution in this event, which is caused by the strong convergence from northern cold air and southwesterly flows in the subtropics. The numerical simulations are further conducted based on WRF model to test the effect of topography near Nanling Mountains on the local precipitation in Hunan. The results show that the reduction or elimination of the Nanling Mountains has limited impact on the overall distribution and amplitude of precipitation near Hunan in this event, but the latitudinal location of precipitation band and its western range slightly change. These changes might be related to the changed local convergence caused by the enhanced southward intrusion of cold air without the blocking of the Nanling Mountains.KeywordsPower line icingTopographyNumerical simulation
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Low temperature together with snow/freezing rain is disastrous in winter over southern China. Previous studies suggest that this is related to the sea surface temperature (SST) anomalies, especially La Niña conditions, over the equatorial central-eastern Pacific Ocean (EP). In reality, however, La Niña episodes are not always accompanied by rainy/snowy/icy (CRSI) days in southern China, such as the case in winter 2020/2021. Is there any other factor that works jointly with the EP SST to affect the winter CRSI weather in southern China? To address this question, CRSI days are defined and calculated based on station observation data, and the related SST anomalies and atmospheric circulations are examined based on the Hadley Centre SST data and the NCEP/NCAR reanalysis data for winters of 1978/1979-2017/2018. The results indicate that the CRSI weather with more CRSI days is featured with both decreased temperature and increased winter precipitation over southern China. The SSTs over both the EP and the southeastern Indian Ocean (SIO) are closely related to the CRSI days in southern China with correlation coefficients of −0.29 and 0.39, significant at the 90% and 95% confidence levels, respectively. The SST over EP affects significantly air temperature, as revealed by previous studies, with cooler EP closely related to the deepened East Asian trough, which benefits stronger East Asian winter monsoon (EAWM) and lower air temperature in southern China. Nevertheless, this paper discovers that the SST over SIO affects precipitation of southern China, with a correlation coefficient of 0.42, significant at the 99% confidence level, with warmer SIO correlated with deepened southern branch trough (SBT) and strengthened western North Pacific anomalous anticyclone (WNPAC), favoring more water vapor convergence and enhanced precipitation in southern China. Given presence of La Niña in both winters, compared to the winter of 2020/2021, the winter of 2021/2022 witnessed more CRSI days, perhaps due to the warmer SIO.
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Background Previous studies have shown that carbon monoxide (CO) poisoning occurs mostly in winter and is associated with severe cold weather (e.g., ice storms, temperature drops). However, according to previous studies, the impact of low temperature on health has a delayed effect, and the existing research cannot fully reveal the delayed effect of cold waves on CO poisoning. Objectives The purpose of this study is to analyze the temporal distribution of CO poisoning in Jinan and to explore the acute effect of cold waves on CO poisoning. Methods We collected emergency call data for CO poisoning in Jinan from 2013 to 2020 and used a time-stratified case-crossover design combined with a conditional logistic regression model to evaluate the impact of the cold wave day and lag 0–8 days on CO poisoning. In addition, 10 definitions of a cold wave were considered to evaluate the impact of different temperature thresholds and durations. Results During the study period, a total of 1,387 cases of CO poisoning in Jinan used the emergency call system, and more than 85% occurred in cold months. Our findings suggest that cold waves are associated with an increased risk of CO poisoning in Jinan. When P01, P05, and P10 (P01, P05, and P10 refer to the 1st, 5th, and 10th percentiles of the lowest temperature, respectively) were used as temperature thresholds for cold waves, the most significant effects (the maximum OR value, which refers to the risk of CO poisoning on cold wave days compared to other days) were 2.53 (95% CI:1.54, 4.16), 2.06 (95% CI:1.57, 2.7), and 1.49 (95% CI:1.27, 1.74), respectively. Conclusion Cold waves are associated with an increased risk of CO poisoning, and the risk increases with lower temperature thresholds and longer cold wave durations. Cold wave warnings should be issued and corresponding protective policies should be formulated to reduce the potential risk of CO poisoning.
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This study analyzed the heaviest snowfalls or icy-rainfalls occurring in southern China from January to the beginning of February 2008. The results are summarized as follows: the disaster was induced by the persistent front of warm/cold air masses in southern China, which displayed an interaction between the weather systems in higher and lower latitudes. There was an adjustment for circulation at hemisphere scale during mid January by a variation of sign of the Arctic Oscillation (AO) index from negative to positive. The long lasting precipitation well coincided with a blocking situation centered near 80°E from mid January to the beginning of February. A diagnostic analysis indicates that stationary waves with an energy dispersion accompanying the blocking high propagated from upstream region in high latitudes to the south of the Yangtze River, which formed a maintaining energy source for the cyclonic circulation in situ. This resulted in that the large mass of cold air in high latitudes could not easily invade into the south but slowly shifted southward. On the other hand, the sea surface temperature (SST) over the warm pool of the western Pacific increased with a new history record due to the effect of the strong La Nina episode, which also blocked the cold air mass from the north. The blocking high collapsed around 30 January and the energy source for the local cyclonic circulation was cut off. Thus, the precipitation in southern China ceased after 1 February.
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The magnitude of flood damage in the United States, combined with the uncertainty in current estimates of flood risk, suggest that society could benefit from improved scientific information about flood risk. To help address this perceived need, a group of researchers initiated an interdisciplinary study of climate variability, scientific uncertainty, and hydrometeorological information for flood-risk decision making, focused on Colorado's Rocky Mountain Front Range urban corridor. We began by investigating scientific research directions that were likely to benefit flood-risk estimation and management, through consultation with climatologists, hydrologists, engineers, and planners. In doing so, we identified several challenges involved in generating new scientific information to aid flood management in the presence of significant scientific and societal uncertainty. This essay presents lessons learned from this study, along with our observations on the complex interactions among scientific information, uncertainty, and societal decision making. It closes by proposing a modification to the "end to end" approach to conducting societally relevant scientific research. Although we illustrate points using examples from flood management, the concepts may be applicable to other arenas, such as global climate change.
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Despite the meteorological community's long-term interest in weather-society interactions, efforts to understand socioeconomic aspects of weather prediction and to incorporate this knowledge into the weather prediction system have yet to reach critical mass. This article aims to reinvigorate interest in societal and economic research and applications (SERA) activities within the meteorological and social science communities by exploring key SERA issues and proposing SERA priorities for the next decade. The priorities were developed by the au thors, building on previous work, with input from a diverse group of social scientists and meteorologists who participated in a SERA workshop in August 2006. The workshop was organized to provide input to the North American regional component of THORPEX: A Global Atmospheric Research Programme, but the priorities identified are broadly applicable to all weather forecast research and applications. To motivate and frame SERA activities, we fi rst discuss the concept of high-impact weather forecasts and the chain from forecast creation to value realization. Next, we present five interconnected SERA priority themes-use of forecast information in decision making, communication of forecast uncertainty, user-relevant verification, economic value of forecasts, and decision support-and propose research integrated across the themes. SERA activities can significantly improve understanding of weather-society interactions to the benefit of the meteorological community and society. However, reaching this potential will require dedicated effort to bring together and maintain a sustainable interdisciplinary community.
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Extraordinarily frequent and long-lasting snowstorms affected China in January 2008, causing abovenormal precipitation, below-normal temperature, and severe icing conditions over central-southern China. These snowstorms were closely linked to the change in the Middle East jet stream (MEJS), which intensified and shifted southeastward. The change in MEJS was accompanied by southeastward shifts of the ridge and the trough over Europe and western Asia. The intensified MEJS also strengthened the trough embedded in the southern branch of the subtropical westerlies over the southern Tibetan Plateau, enhancing the water vapor transport from western Asia and the Bay of Bengal to China. In the meantime, the subtropical western Pacific high (SWPH) was stronger and its ridgeline was farther north than normal. The anomalous high slowed down the eastward propagation of weather systems to the Pacific and favored convergence of water vapor over central-southern China. The MEJS is usually strong when the Arctic Oscillation (AO) is positive and the SWPH is farther north than normal in La Niña winters. Compared to the SWPH and the Niño-3.4 sea surface temperature (SST), the MEJS and the AO exert stronger influences on the temperature and the precipitation over central-southern China, despite the fact that these possible impacting factors are not completely independent from each other. Although the La Niña event might contribute to the climate anomalies through its relation with the SWPH in January 2008, an analysis of historical events indicates that La Niña conditions alone can hardly cause severe and persistent snow conditions over central-southern China. In addition, compared to the Niño-3.4 SST and the SWPH, the conditions of December MEJS and AO exhibit stronger precursory signals of the variability of January temperature over central-southern China.
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Anomalous warming occurred over the Tibetan Plateau (TP) before and during the disastrous freezing rain and heavy snow hitting central and southern China in January 2008. The relationship between the TP warming and this extreme event is investigated with an atmospheric general circulation model. Two perpetual runs were performed. One is forced by the climatological mean sea surface temperatures in January as a control run; and the other has the same model setting as the control run except with an anomalous warming over the TP that mimics the observed temperature anomaly. The numerical results demonstrate that the TP warming induces favorable circulation conditions for the occurrence of this extreme event, which include the deepened lower-level South Asian trough, the enhanced lower-level southwesterly moisture transport in central-southern China, the lower-level cyclonic shear in the southerly flow over southeastern China, and the intensified Middle East jet stream in the middle and upper troposphere. Moreover, the anomalous TP warming results in a remarkable cold anomaly near the surface and a warm anomaly aloft over central China, forming a stable stratified inversion layer that favors the formation of the persistent freezing rain. The possible physical linkages between the TP warming and the relevant resultant circulation anomalies are proposed. The potential reason of the anomalous TP warming during the 2007-08 winter is also discussed.
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In the winter of 2008, China experienced once-in-50-yr (or once in 100 yr for some regions) snow and ice storms. These storms brought huge socio economical impacts upon the Chinese people and government. Although the storms had been predicted, their severity and persistence were largely underestimated. In this study, these cases were revisited and comprehensive analyses of the storms' dynamic and thermodynamic structures were conducted. These snowstorms were also compared with U.S. east coast snowstorms. The results from this study will provide insights on how to improve forecasts for these kinds of snowstorms. The analyses demonstrated that the storms exhibited classic patterns of large-scale circulation common to these types of snowstorms. However, several physical processes were found to be unique and thought to have played crucial roles in intensifying and prolonging China's great snowstorms of 2008. These include a subtropical high over the western Pacific, an upper-level jet stream, and temperature and moisture inversions. The combined effects of these dynamic and thermodynamic structures are responsible for the development of the storms into one of the most disastrous events in Chinese history.
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Interannual variations of the East Asian trough (EAT) axis at 500 hPa are studied with the European Centre for Medium-Range Weather Forecasts 40-yr reanalysis data. The associated circulation pattern and pathway of the East Asian winter monsoon (EAWM) with the EAT axis tilt are specially investigated with a trough axis index, which is closely related to the midlatitude baroclinic process and mainly represents the intensity of the eddy-driven jet over the East Asia–North Pacific sector. When the tilt of EAT is smaller than normal, the EAWM prefers to take the southern pathway and less cold air moves to the central North Pacific. However, the EAWM prefers the eastern pathway and brings more cold air to the North Pacific when the tilt of EAT is larger than normal. These differences induce pronounced changes in both the precipitation and the surface air temperature over East and Southeast Asia. Furthermore, the tilt status of the EAT has a significant modulation effect on the regional climate anomalies related to the intensity of the EAWM. The findings suggest an increase in the temperature anomaly associated with the EAWM intensity and a clear northward–southward shift in its pattern in anomalous tilt phase of the EAT. In addition, the modulation tends to be confined mainly to East Asia and expanded to a larger area during the weak and the strong EAWM winters, respectively. The possible reasons for interannual variations of the EAT tilt are discussed, and it is speculated that the midlatitude air–sea interaction in the North Pacific plays a dominant role. This study on the EAT tilt may enrich knowledge of the East Asian winter monsoon beyond the conventional intensity index and may be helpful to improve regional climate prediction in East Asia.
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A record-breaking, long-persisting extreme cold anomaly (ECA) over Southeast Asia, accompanied by an intraseasonal convection over the Maritime Continent, is identified during the La Niña mature phase in February 2008. The cause of the ECA, in particular the role of the intraseasonal oscillation (ISO) and El Niño–Southern Oscillation (ENSO) on the ECA, is investigated by diagnosing observations and conducting numerical experiments. The ECA is associated with an enhanced prolonged Siberian high (SH) and a persistent northerly anomaly over Southeast Asia. In contrast to conventional cold surges, which are characterized by a synoptic time scale (less than 10 days), the northerly anomaly associated with the ECA persisted for a month or so. The onset of the northerly anomaly is concurrent with a phase change of an ISO over Sumatra. Unlike the normal ISO that continues its eastward journey, the convection associated with this ISO stationed there during all of February 2008. Numerical experiments with an anomaly atmospheric GCM suggest that the ISO heating over the Maritime Continent is responsible for initiating and maintaining the northerly anomaly. The westward progression of the La Niña is crucial for blocking the ISO. The circulation and SST anomalies associated with the La Niña moved westward at a speed of about 15° longitude per month. By early February, the suppressed convective anomaly had moved to the far western Pacific. The westward shift of the cold episode prevented the ISO from moving farther eastward. In addition to its blocking effect, the La Niña also enhanced the heating over the Maritime Continent through the anomalous Walker circulation. Therefore, it is the combined effect of the ISO and ENSO that maintained a prolonged positive heating anomaly, which resulted in a persistent northerly anomaly and thus the ECA.
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Extreme events are significant determinants of the character and evolution of many natural and human systems. When extreme events occur at the interface between natural and human systems, they are often called “disasters.” Here, we use a systemic, contextual view of disasters to construct a framework for organizing research and policy. Within this framework, reduction of vulnerability is the organizing principle, and decision processes (which lead to reduced vulnerability) are the fundamental unit of analysis and action. Scientific research is connected to decision processes through knowledge—integrating activities such as prediction, observation, and heuristics. But the value of research depends on its capacity to enhance decision-making capabilities. Our goal is to define an approach by which policy—relevant research questions can be more readily recognized. and societally valuable (i.e., vulnerabilityreducing) knowledge can be more effectively created and used.
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Disaster associated with natural hazards can lead to important changes—positive or negative—in socio-ecological systems. When disasters occur, much attention is given to the direct disaster impacts as well as relief and recovery operations. Although this focus is important, it is noteworthy that there has been little research on the characteristics and progress of change induced by disasters. Change, as distinct from impacts, encompasses formal and informal responses to disaster events and their direct and indirect impacts. While smaller disasters do not often lead to significant changes in societies and organizational structures, major disasters have the potential to change dominant ways of thinking and acting. Against this background, the article presents an analytical framework for distinguishing change from disaster impacts. Drawing from research in Sri Lanka and Indonesia, formal and informal changes after the Indian Ocean Tsunami of 2004 are examined and discussed against the background of the conceptual framework. The changes examined range from the commencement of the peace process in Aceh, Indonesia, to organizational and legal reforms in Sri Lanka. The article concludes that change-making processes after disasters need to be understood more in depth in order to derive important strategic policy and methodological lessons learned for the future, particularly in view of the increasing complexity and uncertainty in decision making due to climate change. KeywordsDisasters, change-Formal and informal responses-Social learning-Adaptation
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The present paper has made a comparison of major similarities and differences of extreme cold events between the cold and warm periods for recent 50 years, in order to gain a better insight into the impact of the global warming on extreme cold events in China. Two typical events of low temperature, ice freezing and snow disasters that occurred in January 2008 and in the winter of 1954/1955, respectively, are selected as representative cases for the cold period (1950’s–1970’s) and the warm period (1980’s-present). The contrasting study has revealed that these two events both occurred under long-persistent blocking circulation over Eurasian continent, with continuous invasions of strong cold air into China mainland. They nearly brought about similar weather disasters such as extensive low temperature, record-breaking freezing rains and exceptionally heavy snowfalls. However, due to active northward transport of warm and moist air from Bay of Bengal and Indo-China Peninsula in the warm period, the January 2008 case had longer freezing rain days and heavier snowstorms in South China, thus leading to much more severe damage to electric grids and transportations. The case of the 1954/1955 winter was a stronger, extreme cold event than the case of January 2008, in terms of magnitudes of temperature drop and severity of impact on river icing. It was gradually recovered to normal condition while the case of January 2008 had a very rapid recovery to warming condition due to impact of the global warming.
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Large, infrequent disturbances (LID's) can have significant impacts yet are seldom included in management plans. Although this neglect may stem from relative unfamiliarity with the kind of event that rarely occurs in the experience or jurisdiction of individual managers, it may also reflect the assumption that LID's are so large and powerful as to be beyond the ability of managers to affect. However, some LID's can be affected by management, and for many of those that cannot be affected, the resilience or recovery of the system disrupted by the disturbance can be influenced to meet management goals. Such results can be achieved through advance planning that allows for LID's, whether caused by natural events, human activities, or a combination of the two. Management plans for LID's may adopt a variety of goals, depending on the nature of the system and the nature of the anticipated disturbance regime. Managers can choose to influence (a) the system prior to the disturbance, (b) the disturbance itself, (c) the system after disturbance, or (d) The recovery process. Prior to disturbance, the system can be managed in ways to alter its vulnerability or change how it will respond to a disturbance. The disturbance can be managed through no action, preventative measures, or manipulations that can affect the intensity or frequency of the disturbance. Recovery efforts can focus on either managing the ongoing process of recovery. This review of the management implications of LID's suggests that management actions should be tailored to particular disturbance characteristics and management goals. Management actions should foster survival of residuals and spatial heterogeneity that promote pattern and process. Most importantly, however, management plans need to recognise LID's and include the potential for such disturbances to occur.
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This study investigates variability in the intensity of the wintertime Siberian high (SH) by defining a robust SH index (SHI) and correlating it with selected meteorological fields and teleconnection indices. A dramatic trend of –2.5 hPa decade−1 has been found in the SHI between 1978 and 2001 with unprecedented (since 1871) low values of the SHI. The weakening of the SH has been confirmed by analyzing different historical gridded analyses and individual station observations of sea level pressure (SLP) and excluding possible effects from the conversion of surface pressure to SLP. SHI correlation maps with various meteorological fields show that SH impacts on circulation and temperature patterns extend far outside the SH source area extending from the Arctic to the tropical Pacific. Advection of warm air from eastern Europe has been identified as the main mechanism causing milder than normal conditions over the Kara and Laptev Seas in association with a strong SH. Despite the strong impacts of the variability in the SH on climatic variability across the Northern Hemisphere, correlations between the SHI and the main teleconnection indices of the Northern Hemisphere are weak. Regression analysis has shown that teleconnection indices are not able to reproduce the interannual variability and trends in the SH. The inclusion of regional surface temperature in the regression model provides closer agreement between the original and reconstructed SHI.
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Global terrestrial ecosystems absorbed carbon at a rate of 1-4 Pg yr(-1) during the 1980s and 1990s, offsetting 10-60 per cent of the fossil-fuel emissions. The regional patterns and causes of terrestrial carbon sources and sinks, however, remain uncertain. With increasing scientific and political interest in regional aspects of the global carbon cycle, there is a strong impetus to better understand the carbon balance of China. This is not only because China is the world's most populous country and the largest emitter of fossil-fuel CO(2) into the atmosphere, but also because it has experienced regionally distinct land-use histories and climate trends, which together control the carbon budget of its ecosystems. Here we analyse the current terrestrial carbon balance of China and its driving mechanisms during the 1980s and 1990s using three different methods: biomass and soil carbon inventories extrapolated by satellite greenness measurements, ecosystem models and atmospheric inversions. The three methods produce similar estimates of a net carbon sink in the range of 0.19-0.26 Pg carbon (PgC) per year, which is smaller than that in the conterminous United States but comparable to that in geographic Europe. We find that northeast China is a net source of CO(2) to the atmosphere owing to overharvesting and degradation of forests. By contrast, southern China accounts for more than 65 per cent of the carbon sink, which can be attributed to regional climate change, large-scale plantation programmes active since the 1980s and shrub recovery. Shrub recovery is identified as the most uncertain factor contributing to the carbon sink. Our data and model results together indicate that China's terrestrial ecosystems absorbed 28-37 per cent of its cumulated fossil carbon emissions during the 1980s and 1990s.
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China has recently undertaken a sweeping transfer of power to a younger generation of leaders. [ Liu et al .][1] address three major issues that need to be considered by the new leaders as they establish their policies for biodiversity conservation: The process of reserve establishment needs evaluation and the administrative system is not effectively coordinated, reserves are insufficiently funded and seriously understaffed, and more attention to local residents is required. [1]: http://www.sciencemag.org/cgi/content/full/300/5623/1240
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The Asian-Australian monsoon is an important component of the Earth's climate system that influences the societal and economic activity of roughly half the world's population. The past strength of the rain-bearing East Asian summer monsoon can be reconstructed with archives such as cave deposits, but the winter monsoon has no such signature in the hydrological cycle and has thus proved difficult to reconstruct. Here we present high-resolution records of the magnetic properties and the titanium content of the sediments of Lake Huguang Maar in coastal southeast China over the past 16,000 years, which we use as proxies for the strength of the winter monsoon winds. We find evidence for stronger winter monsoon winds before the Bølling-Allerød warming, during the Younger Dryas episode and during the middle and late Holocene, when cave stalagmites suggest weaker summer monsoons. We conclude that this anticorrelation is best explained by migrations in the intertropical convergence zone. Similar migrations of the intertropical convergence zone have been observed in Central America for the period ad 700 to 900 (refs 4-6), suggesting global climatic changes at that time. From the coincidence in timing, we suggest that these migrations in the tropical rain belt could have contributed to the declines of both the Tang dynasty in China and the Classic Maya in Central America.
Article
Four successive freezing rain/heavy snowfall processes occurred in the southern part of China from 11 January to 2 February 2008 (named "0801 Southern Snow Disaster" hereafter), during which a large-scale blocking circulation lasted for a long time over the mid-high latitudes of the Euro-Asian continent. This severe event is featured with a broad spatial scale, strong intensity, long duration, and serious damage. During the event, the blocking situation in the mid-high latitudes maintained quasi-sationary, but weather systems in the lower latitudes were active. Abundant water vapor was supplied, and favorable weather conditions for ice storms were formed over the large areas across the southern part of China. The results in this paper demonstrate that the significant factors responsible for the abnormal atmospheric circulation and this severe event include: 1) the very active Arctic Oscillation (AO), which helped the permanent maintenance of the planetary-scale waves; 2) the continuous transfer of negative vorticity from the upstream region around 50 degrees E into the blocking area, which caused the blocking situation reinforced repeatedly and sustained for a long time; and 3) the active air currents south of the Tibetan Plateau, which ensured abundant moisture supply to the southern areas of China. The 0801 Southern Snow Disaster was accompanied by extremely severe icing. In this paper, the data from Cloud-Profile Radar onboard the satellite CloudSat are used to study the dynamic and microphysical features of this event. The results show that there existed a melting layer between 2 and 4 km, and ice particles could be found above this layer and in the layer near the ground surface. Surface temperature kept between -4 degrees C and 0 degrees C with relative humidity over 90%, which provided the descending supercooled waterdrops with favorable synoptic and physical conditions to form glaze and ice at the surface via freezing, deposition and/or accretion. Causes of the event might be, as a whole, traced back to the planetary-scale systems. The study on the polar vortex anomaly in this paper reveals that changes in the polar vortex in the stratosphere preceded those in the troposphere, especially in early December 2007, while the intensification of the polar vortex in the troposphere delayed dramatically until middle January and early February of 2008. This implies that changes in the polar vortex in the stratosphere may be a precursor of the ensuing severe event and a meaningful clue for extended forecasts of such a disaster.
Article
South China suffered an extremely severe disaster caused by low-temperature and ice-snow during the last 20 days of January 2008. The freezing rain and snow are climatologically related to the South China quasistationary front (SCQSF) in mid winter. The three-dimensional structure of the SCQSF was examined based on the weather charts, the sounding profiles, and the vertical cross-sections using the method of classical synoptic analysis.
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Freezing rainstorms in the United States during 1949-2000 resulted in 87 catastrophic events, storms causing property losses of more than 1million,withresultinglossestotaling1 million, with resulting losses totaling 16.3 billion. Catastrophes and their losses were greatest in the northeast, southeast, and central United States, and only 3% occurred in the western United States. A greater percentage of the freezing-rain occurrences in the deep South produced catastrophes than did freezing-rain occurrences in the northern United States, a result of differences in storm-producing conditions. A dense network of observers who measured ice storms during a 9-yr period provided definitive data on damaging storm areas and ice thicknesses on wires. The geographic distribution of the 368 damaging-ice storm areas matched well with that of catastrophes; both were greatest in a belt from the Southwest, across the Midwest, and into New England. Storm-area sizes ranged from 205 to 796 000 km2, with 50% being less than 21 840 km2. Most storm-area shapes were elongated with length-width ratios from 2:1 up to 15:1, although 18% were oblate shaped, particularly those in the northern High Plains and upper Midwest. Two-thirds of the ice-storm areas and catastrophe loss patterns assumed one of seven spatial types. The most prevalent type was a storm restricted to the Northeast, the second had losses in the Midwest and Northeast, and third was a storm in both the Northeast and Southeast regions. Five large-sized catastrophes extended from the Southwest, through the Midwest, into the Northeast, and these caused $3.5 billion in losses, 21% of the 52-yr total. The radial thickness of damaging ice on telegraph wires was sampled at 1689 sites, and the greatest average (>1.3 cm) and maximum (>5 cm) sizes occurred in the deep South and southern plains where storms have long durations and ample moisture aloft. Maximum and average ice thickness were relatively large in New England and the Northeast. Ice-thickness values were least in the upper Midwest and Pacific Northwest. The results collectively show that the greatest risk of ice-storm damages (based on event frequency, ice thickness, storm size and shape, and financial loss) is in the northeastern United States, followed by the risk in the lower Midwest and that in the southern United States.
Article
The ice storm of 5-9 January 1998, affecting the northeastern United States and the eastern Canadian provinces, was characterized by freezing rain amounts greater than 100 mm in some areas. The event was associated with a 1000-500-hPa positive (warm) thickness anomaly, whose 5-day mean exceeded + 30 dam (+ 15°C) over much of New York and Pennsylvania. The region of maximum precipitation occurred in a deformation zone between an animalously cold surface anticyclone to the north and a surface trough axis extending from the Gulf of Mexico into the Great Lakes. The thermodynamic impact of this unprecedented event was studied with the use of a four-dimensional data assimilation spanning an 18-day period ending at 0000 UTC 9 January 1998. A moisture budget for the precipitation region reveals the bulk of the precipitation to be associated with the convergence of water vapor transport throughout the precipitation period. The ice storm consisted of two primary synoptic-scale cyclonic events. The first event was characterized by trajectories arriving in the precipitation zone that had been warmed and moistened by fluxes over the Gulf Stream Current and the Gulf of Mexico. The second and more significant event was associated with air parcels arriving in the precipitation zone that had been warmed and moistened for a period of several days in the planetary boundary layer (PBL) of the subtropical Atlantic Ocean. These parcels had equivalent potential temperatures of approximately 330 K at 800 hPa as they traveled into the ice storm's precipitation zone. Analogs to this unprecedented meteorological event were sought by examining anomaly correlations (ACs) of sea level pressure, and 1000-925 and 1000-500-hPa thickness. Five analogs to the ice storm were found, four of which are characterized by extensive freezing rain. The best analog, that of 22-27 January 1967, is characterized by freezing rain extending from the northeastern United States into central Ontario. However, the maximum amounts are less than 50% of the 1998 case. An examination of air parcel trajectories for the 1967 case reveals a similar-appearing horizontal spatial structure of trajectories, with several travelling anticyclonically from the subtropical regions of the eastern Atlantic. However, a crucial distinguishing characteristic of these trajectories in the 1967 case is that the air parcels arriving in the precipitation zone had equivalent potential temperature values of only 310 K, as compared with 330 K for the 1998 ice storm trajectories. It was found that these air parcels had traveled above the PBL and, therefore, had not been warmed and moistened by fluxes from the subtropical oceans.
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A half-century policy of forest exploitation and monoculture in China has led to disastrous consequences, including degradation of forests and landscapes, loss of biodiversity, unacceptable levels of soil erosion, and catastrophic flooding. A new forest policy had been adopted in China called the Natural Forest conservation Program (NFCP), which emphasizes expansion of natural forests and increasing the productivity of forest plantations. Through locally focused management strategies, biodiversity and forest resources will be sustained, and downstream regions will be better protected from flooding. This new policy is being implemented with a new combination of policy tools, including technical training and education, land management planning, mandatory conversion of marginal farmlands to forest, resettlement and retaining of forest dwellers, share in private ownership, and expanded research. These policy tools may have wider relevance for other countries, particularly developing countries.
Book
The ruined cities, temples, and statues of history's great, vanished societies (Easter Island, Anasazi, the Lowland Maya, Angkor Wat, Great Zimbabwe and many more) are the birthplace of endless romantic mysteries. But these disappearances offer more than idle conjecture: the social collapses were due in part to the types of environmental problems that beset us today. Yet many societies facing similar problems do not collapse. What makes certain societies especially vulnerable? Why didn't their leaders perceive and solve their environmental problems? What can we learn from their fates, and what can we do differently today to help us avoid their fates?
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Last week, China's State Forestry Administration announced that winter storms have damaged 20.86 million hectares--one-tenth of China's forests and plantations--roughly equivalent to the number of hectares that were reforested between 2003 and 2006.
Article
The unprecedented snow disaster in January 2008 brought serious human and economic losses to China. It has been suggested that the La Nina event is the principal cause. But analysis indicates that in December 2007, the circulation patterns in the tropical regions are quite similar with those in January 2008. In contrast large differences existed at high latitudes, especially the Siberia high (SH) and the north polar vortex (NPV). The differences can also be found between other extreme heavy and light snow years. In the extreme heavy (light) snow years, the SH is stronger (weaker) and the NPV is deeper (shallower). But these extreme snow events don't correspond to ENSO events well. Statistical results also indicate that both the SH and the NPV are independent of ENSO. So, rather than the La Nina event, the abnormal circulations at the high latitudes may play a more crucial role in making this snow disaster. Copyright © 2009 Royal Meteorological Society
Article
This paper examines the main causes ofthe 1998 flood on the Yangtze and addresses a numberof issues related to the exploitation of naturalresources and counter-measures to the flood hazard.The records show that both the amount of precipitationover the catchment and the floodwater discharge fromthe upper basin did not exceed the historical maximum,but water levels in the middle basin were recordedmuch higher than the historical maximum. Humanactivities have greatly increased the risk of theflood hazard. Extensive reclamation of the lakes andfluvial islands in the middle basin has considerablyreduced the floodwater storage and drainage capacityof these natural landscapes of the Yangtze Basin.Deforestation in the catchment area has induced soilerosion, resulting in a large amount of sedimentdeposited in reservoirs whose storage capacity is thusreduced. Strengthening the flood defence to protectpeople living on the floodplain has raised the waterlevel during the flood. An integrated approach isneeded to produce a balanced management plan that canmeet the financial needs of local people in thecatchment area as well as reduce flood risk to theindustries and urban residents in the middle basin ofthe Yangtze.
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A regular graph X is called semisymmetric if it is edge-transitive but not vertex-transitive. For G ≤ AutX, we call a G-cover X semisymmetric if X is semisymmetric, and call a G-cover X one-regular if AutX acts regularly on its arc-set. In this paper, we give the sufficient and necessary conditions for the existence of one-regular or semisymmetric Z n -covers of K 3,3. Also, an infinite family of semisymmetric Z n × Z n -covers of K 3,3 are constructed.
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This review explores the ecological and silvicultural impacts of ice storms on forests in the southern United States. Different environmental factors like weather conditions, topography, vegetation, stand density, and management practices influence the degree of glaze damage a particular forest may experience. Additionally, the frequent contradictions in the relationships between these factors and the resulting damage suggests a complexity that makes each ice storm unique and difficult to predict. We recommend a series of silvicultural responses to ice storms, including density management, planting species selection, post-event evaluation, salvage, stand rehabilitation, and long-term monitoring of forest health.
Article
A half-century policy of forest exploitation and monoculture in China has led to disastrous consequences, including degradation of forests and landscapes, loss of biodiversity, unacceptable levels of soil erosion, and catastrophic flooding. A new forest policy had been adopted in China called the Natural Forest conservation Program (NFCP), which emphasizes expansion of natural forests and increasing the productivity of forest plantations. Through locally focused management strategies, biodiversity and forest resources will be sustained, and downstream regions will be better protected from flooding. This new policy is being implemented with a new combination of policy tools, including technical training and education, land management planning, mandatory conversion of marginal farmlands to forest, resettlement and retaining of forest dwellers, share in private ownership, and expanded research. These policy tools may have wider relevance for other countries, particularly developing countries.
Article
Ice storms, or icing events, are important meteorological disturbances affecting forests over a surprisingly large portion of the USA. A broad belt extending from east Texas to New England experiences major ice storms at least once a decade; and truly major events occur in the heart of this belt once or twice a century. In the areas most affected, icing events are a factor that shapes stand composition, structure, and condition over wide areas. Impacts of individual storms are highly patchy and variable, and depend on the nature of the storm. Impacts also depend on how (or if) forest managers conduct subsequent salvage cuttings. Important research needs remain to be considered by the forest ecology and meteorology communities. At present, how ice storm frequency and severity may change with future climate change is unknown.
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How China and the rest of the world affect each other.
Article
To address devastating environmental crises and to improve human well-being, China has been implementing a number of national policies on payments for ecosystem services. Two of them, the Natural Forest Conservation Program (NFCP) and the Grain to Green Program (GTGP), are among the biggest programs in the world because of their ambitious goals, massive scales, huge payments, and potentially enormous impacts. The NFCP conserves natural forests through logging bans and afforestation with incentives to forest enterprises, whereas the GTGP converts cropland on steep slopes to forest and grassland by providing farmers with grain and cash subsidies. Overall ecological effects are beneficial, and socioeconomic effects are mostly positive. Whereas there are time lags in ecological effects, socioeconomic effects are more immediate. Both the NFCP and the GTGP also have global implications because they increase vegetative cover, enhance carbon sequestration, and reduce dust to other countries by controlling soil erosion. The future impacts of these programs may be even bigger. Extended payments for the GTGP have recently been approved by the central government for up to 8 years. The NFCP is likely to follow suit and receive renewed payments. To make these programs more effective, we recommend systematic planning, diversified funding, effective compensation, integrated research, and comprehensive monitoring. Effective implementation of these programs can also provide important experiences and lessons for other ecosystem service payment programs in China and many other parts of the world. • conservation • environment • forests • grassland • sustainability
Impacts of a severe snow storm and freezing rain over southern China
  • L Zhao
Zhao, L., and Coauthors, 2008: Impacts of a severe snow storm and freezing rain over southern China in January 2008 (in Chinese). Climatic Environ. Res., 13, 556-566.
Interannual variations of East Asian trough axis at 500 hPa and its association with the East Asian winter monsoon pathway Forest fire occurrence in short term under the impacts of snow damage in south China— Case study in Hunan Province
  • W Chen
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—, W. Chen, W. Zhou, and R. Huang, 2009: Interannual variations of East Asian trough axis at 500 hPa and its association with the East Asian winter monsoon pathway. J. Climate, 22, 600–614. 59 january 2011 aMErICan METEOrOLOGICaL SOCIETy | Wang, M., L. Shu, Q. Wang, F. Zhao, X. Tian, H. Yan, and J. Du, 2008: Forest fire occurrence in short term under the impacts of snow damage in south China— Case study in Hunan Province (in Chinese). Sci. Silvae Sin., 44, 64–68.
Analysis of the severe cold surge, ice-snow and frozen disasters in south China during
  • L Wang
Wang, L., and Coauthors, 2008: Analysis of the severe cold surge, ice-snow and frozen disasters in south China during January 2008. I. Climatic features and impact (in Chinese). Meteor. Mon., 34, 95–100.
Repairing the electric power grid. China Electricity Council Rep. 31. [Available online at www.cec.org.cn/news/showc. asp?id=102146
  • China Electricity Council
China Electricity Council, 2008: Repairing the electric power grid. China Electricity Council Rep. 31. [Available online at www.cec.org.cn/news/showc. asp?id=102146.]
The impact of snowstorm on apiculture and its forecast in the low-middle Yangtze River
  • T Jin
  • C Chen
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Jin, T., C. Chen, J. Luo, B. Sun, J. Shi, and E. Ni, 2008: The impact of snowstorm on apiculture and its forecast in the low-middle Yangtze River (in Chinese).
The impact of snowstorm on the bee population and its solutions (in Chinese)
  • Z Li
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Li, Z., and J. Wang, 2008: The impact of snowstorm on the bee population and its solutions (in Chinese). J. Bee, 3, 15.
A rare snowstorm disaster in China (in Chinese)
  • K Peng
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Peng, K., and H. Peng, 2008: A rare snowstorm disaster in China (in Chinese). Sci. News, 5, 15-17.
Analysis of the long-lasting cryogenic freezing rain and snow weather in the beginning of
  • G Yang
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  • F Zhang
  • Z Kang
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Yang, G., Q. Kong, D. Mao, F. Zhang, Z. Kang, and Z. Zong, 2008: Analysis of the long-lasting cryogenic freezing rain and snow weather in the beginning of 2008 (in Chinese). Acta Meteor. Sin., 66, 836-849.
Diagnosis of catastrophic freezing rain and sleet in
  • X Ma
Ma, X., 2009: Diagnosis of catastrophic freezing rain and sleet in January 2008 in southern China (in Chinese).
Characteristics of meteorological disasters caused by the extreme synoptic process in early 2008 over China (in Chinese)
  • Z Wang
  • Q Zhang
  • Y Chen
  • S Zhao
  • H Zeng
  • Y Zhang
  • Q Liu
Wang, Z., Q. Zhang, Y. Chen, S. Zhao, H. Zeng, Y. Zhang, and Q. Liu, 2008: Characteristics of meteorological disasters caused by the extreme synoptic process in early 2008 over China (in Chinese). Adv. Climate Change Res., 4, 63-67.
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