Yang Chen

Chinese Academy of Meteorological Sciences · Climate Resear Unit

In summer 2021, the Northwestern Pacific and Northeast Asia were both hit by extraordinary heat waves with record-breaking high temperature. The marine heat caused an unprecedented outbreak of red tides off Hokkaido and decimated the local fishery industry, while the extreme terrestrial heat made the Tokyo 2020 Olympics the hottest Games in history...

When co-occurring with elevated levels of ambient relative humidity (RH), hot extremes are more perceivable and consequently more health-damaging. Quantifying changes in humid-heat extremes has therefore gained considerable scientific and societal attention, but a fundamental yet critical aspect to the estimation—data reliability—has been largely d...

The 2021 northwest Pacific marine heatwave was favored by the atmospheric and oceanic conditions; changes in the mean climate due to anthropogenic warming made the event 43 times more likely.

Tropical cyclones (TCs) and heatwaves are amongst the most deadly and costly natural hazards. Despite considerable advances in understanding each of them, their occurrences in rapid sequence (e.g., in a week) that introduce disproportionately large impacts to infrastructure and human health have received far less attention. Based on dynamical downs...

Plain Language Summary Despite plentiful knowledge on heatwaves' impacts on human health, little has been known about heatwaves' implication for extreme rainfall and the resulting floods. After experiencing sustained sweltering weather, people are sometimes eager for cooling brought about by heavy precipitation; however, subsequent rainfall, if int...

Plain Language Summary Co‐occurrences of wind extremes and precipitation extremes, termed compound wind and precipitation extremes (CWPEs), can disrupt and endanger shipment and shipping logistics. The associated winds and floods may cause severe socio‐economic impacts in coastal and inland areas, such as paralyzed public transportation, critical i...

There have been considerable high-impact extreme events occurring around the world in the context of climate change. Event attribution studies, which seek to quantitatively answer whether and to what extent anthropogenic climate change has altered the characteristics—predominantly the probability and magnitude—of particular events, have been gainin...

Urban areas are experiencing strongly increasing hot temperature extremes. However, these urban heat events have seldom been the focus of traditional detection and attribution analysis designed for regional to global changes. Here we show that compound (day–night sustained) hot extremes are more dangerous than solely daytime or nighttime heat, espe...

Plain Language Summary Policy‐makers and stakeholders have long been informed of that climate change has altered and continues to alter the profile of extremes, for example, frequency, magnitude, duration, and/or seasonality, creating unprecedented events with catastrophic consequences. But they have been seldom told that a changing climate is also...

Future changes in the frequency of extreme drought events are of vital importance for risk assessment and relevant policy making. But a reliable estimation of their probability is intrinsically challenging due to limited available observations or simulations. Here, we use two large ensemble simulations, 50 members from CanESM2 and 40 members from C...

Traditional univariate analysis on weather and climate extremes failed to consider temporally compounding events and the resulting cascading impacts. A case in point is a sequence of flood and heatwave within a week, which slows recovery and amplifies damages. We show that across China, floods and heatwaves seldom occurred serially within seven day...

Anthropogenic forcings have reduced the likelihood of heavy precipitation in southern China like the 2019 March–July event by about 60%

Key Points Unprecedented compound heat waves will occur on a regular basis in three urban agglomerations in China since mid‐21st century under RCP8.5 The likelihood of unprecedented compound heat waves in a 1.5°C warmer world will halve compared to 2°C warming scenario Population exposures to future unprecedented compound heat waves will increase b...

Understanding the driving factors for precipitation extremes matters for adaptation and mitigation measures against the changing hydrometeorological hazards in Yangtze River basin, a habitable area that provides water resources for domestic, farming, and industrial needs. However, the region is naturally subject to major floods linked to monsoonal...

Detecting long-term changes in precipitation extremes over monsoon regions remains challenging, due to large observational uncertainty, high internal variability at the regional scale and climate models’ deficiency in simulating monsoon physics. This is particularly true for Eastern China, as illustrated by limited yet controversial detection resul...

It has been long appreciated that precipitation falls unevenly in time, but the degree of unevenness and its changes with warming have been seldomly quantified. These quantifications, however, matter to various sectors (e.g. crop and livestock yields) for addressing evolutionary hydro-meteorological hazards. Using gauge observations at hourly- and...

The detection and attribution of precipitation changes are fundamental for adaptation and mitigation planning. Based on high‐quality observations, we determined the detectability of the trends of multiple precipitation characteristics across China using a field significance test. Furthermore, the timing at which spatially aggregated changes become...

Short duration extreme precipitation has devastating Impacts on city area. Local urbanization effects, superimposed upon regional climate change, complicate examination of long‐term changes in short duration precipitation extremes in urban areas. Based on high‐quality rain gauge observations of summertime hourly precipitation in Beijing Region over...

Plain Language Summary Summer precipitation in eastern China has exhibited a “southern flood‐northern drought (SFND)” pattern during the past few decades. Despite substantial literature attempting to explain the phenomenon, efforts devoted to the quantification of contributions from dynamic processes (changes in daily atmospheric circulations) and...

Compared to individual hot days/nights, compound hot extremes that combine daytime and nighttime heat are more impactful. However, past and future changes in compound hot extremes as well as their underlying drivers and societal impacts remain poorly understood. Here we show that during 1960–2012, significant increases in Northern Hemisphere averag...

Southern China was hit by a severe cold event during January 21‐25, 2016, characteristic of a drastic and sudden temperature drop, with new records of low temperatures set in widespread areas. This cold event was dynamically linked to the activity of the Arctic Oscillation (AO) whose evolution led the event by about two weeks. Different from this s...

Despite intense discussions on the recent boom of mid-latitude wintertime cold extremes, co-variations of warm and cold extremes, i.e. winter temperature volatility, has garnered substantially less attention. Apart from using temperature extremes' frequency and intensity, we also define 'temperature whiplash', which depicts rapid switches between w...

Abstract The Paris Agreement has motivated rapid analysis differentiating changes in frequency/intensity of weather and climate extremes in 1.5 versus 2 °C warmer worlds. However, implications of these global warming levels on locations, spatial scales, and emergence timings of hot spots to extremes are more relevant to policy‐making but remain str...

This study investigates whether and how three synoptic‐scale teleconnections, i.e. East Asia/Pacific teleconnection (EAP), Silk‐road teleconnection (SR) and Eurasia teleconnection (EU), induce persistent precipitation extremes (PPEs) in the Yangtze River Valley. Results show that only the EAP teleconnection has the potential of independently incurr...

On 21-25 July 2017 a record-breaking heatwave occurred in Central Eastern China, affecting nearly half of the national population and causing severe impacts on public health, agriculture and infrastructure. Here, we compare attribution results from two UK Met Office Hadley Centre models, HadGEM3-GA6 and [email protected] (HadAM3P driving 50 km HadR...

Weather and climate extremes impose serious impacts on natural and human systems. In its fifth assessment report (AR5) and a special report Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation (SREX), the Intergovernmental Panel on Climate Change provided a thorough assessment of observed and projected changes in...

This paper reviews recent progress in climate change attribution studies. The focus is on the attribution of observed long-term changes in surface temperature, precipitation, circulation, and extremes, as well as that of specific extreme weather and climate events. Based on new methods and better models and observations, the latest studies further...

Avoided risks in a 1.5°C warmer world as opposed to a 2°C one become urgent to be assessed after the Paris Agreement, especially at regional scales. To provide an observable analog, this study quantified detectable impacts of the past 0.5°C global warming on summertime hot extremes in China. The half-degree global warming has preferentially facilit...

Projected changes of the thermal growing season (TGS) over Northern Eurasia at 1.5 °C and 2 °C global warming levels are investigated using 22 CMIP5 models under both RCP4.5 and RCP8.5 scenarios. The multi-model mean projections indicate Northern Eurasia will experience extended and intensified TGSs in a warmer world. The prolongation of TGSs under...

Studies on the effects of 1.5 °C global warming above pre-industrial levels, especially in megacities, are very limited. Here, we review recent progress in understanding climate change-related extreme temperature and precipitation events in China's megacities, and provide some potential options for adaptation. Studies have indicated that both globa...

In this study, cases of the East Asia-Pacific (EAP) teleconnection pattern not responsible for persistent precipitation processes in the Yangtze River valley (YRV) have been investigated. The results suggest that such a type of EAP pattern has some linkage with persistent precipitation processes in south China (SC) with the following properties: 1)...

The boreal summer intraseasonal oscillation (BSISO), including a 30–60 day component (BSISO1) and a quasi-biweekly component (BSISO2), is the most prominent form of subtropical intraseasonal variability. Influences of BSISOs on summertime precipitation and temperature extremes in China are examined. Results indicate that BSISOs can simultaneously f...

During the past two decades since 1997, eastern China has experienced a warming hiatus punctuated by significant cooling in daily-minimum temperature (Tmin), particularly during early–mid winter. By arbitrarily configuring start and end years, a 'vantage hiatus period' in eastern China is detected over 1998–2013, during when the domain-averaged Tmi...

Summertime hot extremes in China are categorized into three distinct types, i.e. independent hot days, independent hot nights and compound events, based on differing configurations between daily maximum and minimum temperature. Linear trends for multiple indictors of these subtypes and traditionally-defined hot days/nights exhibited remarkable diff...

Based on the property of entropy, a new index Q was defined to measure the temporal concentration property of summertime daily rainfall in China, based on daily precipitation data collected at 553 observation stations in China during 1961–2010. Furthermore, changes in the temporal concentration property of summer precipitation in China were investi...

Using observed daily temperatures in China, three independent types of heat waves (HWs), including daytime HWs, nighttime HWs, and compound HWs (with both extreme daily maxima and minima), were defined. Different types of HWs showed distinctive preferences in occurrence locations and timing. However, spatial patterns of accompanying relative humidi...

Concurrent position shifts of the mid-level western Pacific subtropical high (WPSH) and the upper-level South Asia high (SAH) are regarded as significant precursors for persistent extreme precipitation events (PEPEs) in the Yangtze River Valley (YRV). By performing composite analyses, accountable vorticity genesis and dissipation are diagnosed base...

Based on observational precipitation at 63 stations in South China and NCEP–NCAR reanalysis data during 1951–2010, a cluster analysis is performed to classify large-scale circulation patterns responsible for persistent precipitation extremes (PPEs) that are independent of the influence of tropical cyclones (TCs). Conceptual schematics depicting con...

Based on the daily reanalysis data from NCEP–NCAR and daily precipitation data from the China National Meteorological Information Center, an ensemble empirical mode decomposition method is employed to extract the predominant oscillation modes of the East Asia–Pacific (EAP) teleconnection pattern. The influences of these low-frequency modes on persi...

The East Asia/Pacific (EAP) teleconnection can substantially modulate weather anomalies over eastern Asia during summer. Wavelet analyses, including ensemble mean power spectrum and accumulated frequency of significant components, highlight 10–30-day oscillations in the EAP index. The influences of these low-frequency oscillations on weather anomal...

The western Sichuan Basin (WSB) is a rainstorm center influenced by complicated factors such as topography and circulation. Based on multivariable empirical orthogonal function technique for extreme precipitation processes (EPP) in WSB in 2013, this study reveals the dominant circulation patterns. Results indicate that the leading modes are charact...

This study mainly presents recent progresses on persistent extreme precipitation events (PEPEs) in East China. A definition focusing both persistence and extremity of daily precipitation is firstly proposed. An identification method for quasi-stationary regional PEPEs is then designed. By utilizing the identified PEPEs in East China, typical circul...

Two types of persistent extreme weather events, the cold–wet spell (CWS) and the persistent wet-freezing event (PWFE), are defined by considering the persistence of both extreme low temperature (ELT) and precipitation. Regional CWS and PWFE are identified based on temporal persistence and spatial contiguity of single-station-based CWS event and PWF...

Synoptic-scale precursors of typical East Asia/ Pacific (EAP) teleconnection pattern responsible for persistent extreme precipitation events (PEPEs) in the Yangtze River Valley (YRV) are investigated based on a composite analysis. The results reveal that about one week prior to PEPEs, a blocking high develops near the Sea of Okhotsk owing to an eas...

Using homogenized daily precipitation observations during 1961 to 2012, changes in duration-based structure of precipitation over southwest China under drought conditions were investigated. The results reveal a distinct regrouping of wet periods of different length. Wet days and precipitation related to long wet periods (>3 d) decreased significant...

Two characteristic circulation patterns responsible for persistent extreme precipitation (PEP) events in Central–Eastern China are identified using a composite analysis: a double-blocking high type and a single-blocking high type. The double-blocking high type is characterized by the development of two blocking highs near the Ural Mountains and the...

Using a composite analysis, the typical precursor circulation configuration from the lower to the upper troposphere responsible for persistent extreme precipitation events (PEPEs) of double-blocking-high type in central-eastern China is identified. The potential of these precursors is further assessed based on the composites of normalized anomalies...

Persistent extreme precipitation events (PEPEs) in China are investigated in the context of a new definition that considers both the persistence and the extremity of daily precipitation at individual stations. An identification method for regional PEPEs is designed based on joint application of this definition and a spatial contiguity criterion. Be...