David Dian Zhang

Guangzhou University · School of Geographical Sciences

The ancient Silk Road played a crucial role in cultural exchange and commercial trade between western and eastern Eurasia during the historical period. However, the exchanges were interrupted in the early 16th century CE, during the Ming dynasty. Various causes for the decline of the ancient Silk Road have been suggested. Unlike social factors, nat...

Studies on the spatiotemporal relationship between historical climate change and the patterns of population and war are rare. In this research, statistical methods (such as correlation test and Granger causality analysis) and visualization technique are applied to demonstrate how temperature, in terms of long-term trend and cyclic mode, fundamental...

The Ancient Silk Road played a crucial role in cultural exchange and commercial trade between western and eastern Eurasia during the historical period. However, the exchanges were interrupted in the early 16th century AD, in the Ming dynasty. Three causes of the demise of the ancient Silk Road have been suggested: (1) the thriving of the sea trade...

Quantitative research on climate change and war hot spots throughout history is lacking. In this study, the spatial distribution and dynamic process of war hot spots under different climatic phases in imperial China (1–1911 CE) are revealed using Emerging Hot Spot Analysis (EHSA), based on the Global Moran’s Index for testing the degree of spatial...

Studies about climate change and the variation of the spatial pattern of war are extremely scarce in academia at present. Therefore, the temperature series and battle coordinates in imperial China from AD 5 to 1911 are integrated in this research, and their long-term quantitative relationship is examined by employing mathematical statistics such as...

Wendelstein 7-X is the first comprehensively optimized stellarator aiming at good confinement with plasma parameters relevant to a future stellarator power plant. Plasma operation started in 2015 using a limiter configuration. After installing an uncooled magnetic island divertor, extending the energy limit from 4 to 80 MJ, operation continued in 2...

For the first time, the optimized stellarator Wendelstein 7-X has operated with an island divertor. An operation regime in hydrogen was found in which the total plasma radiation approached the absorbed heating power without noticeable loss of stored energy. The divertor thermography recorded simultaneously a strong reduction of the heat load on all...

The temperature variation in China is closely related to the dynamics of global climate change. In order to reveal its possible connections with global climate during the Holocene, we present a nationwide temperature reconstruction in China for the past 12,000 years, based on multiple proxies with three statistical methods, including empirical orth...

Optically stimulated luminescence (OSL) dating was conducted on the K-feldspar and quartz fractions of a Holocene loess-paleosol sequence in the Yili Basin, in the core area of arid central Asia (ACA). Age overestimation using the post-IR IR (pIR 50 IR 170 ) signals from feldspar was observed for paleosols, because of poor bleaching prior to deposi...

Researchers mostly ascribe contemporary natural disaster and the concomitant social crisis to anomalous climate change or global warming. However, whether such a relationship is still valid in long-term historical settings remains doubtful. In this study, data obtained from historical records about natural calamities (flood and drought) and their s...

The nomad–agriculturalist conflicts under the influence of climate change are investigated with the case of China in 965–1805 CE (mid-to-late Imperial China). Quantitative approach has been adopted with the supplement of qualitative method to re-interpret the conflicts at the long-term national scale under the paradigm of environmental humanities....

Electron temperature gradient (ETG)-driven turbulence, despite its ultrafine scale, is thought to drive significant thermal losses in magnetic fusion devices - but what role does it play in stellarators? The first numerical simulations of ETG turbulence for the Wendelstein 7-X stellarator, together with power balance analysis from its initial exper...

This study examines China's urban-rural transition in the process of development and change. Regarding tourism as a discourse of difference, it focuses on a rural ethnic community, Jiabang, in Southwest China. It aims to highlight the role of tourism in providing a stimulus for the creation of a local group identity that subverts wider discourses o...

Recent studies show that wars were more prevalent during colder periods in human history. Nevertheless, the temporal consistency of the climate-war correlation in Europe over extended period has rarely been examined systematically. In this study, we extended the European violent conflict record in the Conflict Catalog [Brecke 1999. “Violent conflic...

The Yellow River flow has decreased substantially in recent decades, and the river often dried up in the lower reach and failed to reach the sea. Climate change and human disruption have been suggested as major causes of the flow reduction, but quantification of their relative contribution is challenging due to limited instrumental records and dist...

Accurate water mapping depends largely on the water index. However, most previously widely-adopted water index methods are developed from 30-m resolution Landsat imagery, with low-albedo commission error (e.g., shadow misclassified as water) and threshold instability being identified as the primary issues. Besides, since the shortwave-infrared (SWI...

Effective power exhaust by impurity seeding and its dependence on the gas species used was demonstrated in island divertor configurations for the first time at Wendelstein 7-X (W7-X). A systematic set of experiments has been conducted during the first island divertor campaign which show that switching from Neon (Ne) to nitrogen (N 2) as seeding gas...

China’s industrialization after the 1840s has been mainly regarded as a reaction to external shocks from Western countries. However, Rostow’s stages of growth theory states that industrialization should be achieved by adequate groundwork of agrarian economy. In this context, this study aims to quantitatively analyze China’s industrialization from 1...

Long-term, high-resolution temperature records which combine an unambiguous proxy and precise dating are rare in China. In addition, the societal implications of past temperature change on a regional scale have not been sufficiently assessed. Here, based on the modern relationship between chironomids and temperature, we use fossil chironomid assemb...

Based on 1686 records of agriculturalists’ migration and 4417 events of social crisis (wars, famines, and epidemics) together with various statistical methods, we constructed a conceptual model that includes both climatic and social factors to explain the long-term dynamics of agriculturalists’ migration in historical China over the last two millen...

Although many large-N quantitative studies have evidenced the adverse effects of climatic extremes on social stability in China during the historical period, most of them rely on temperature and precipitation as major explanatory variables, while the influence of floods and droughts on social crises is rarely measured. Furthermore, a comparison of...

众多的大数据定量研究证明了在历史时期，极端气候变化能造成中国社会不稳定。但是，已有的研究将温度和降水量作为主要解析变量，欠缺了旱涝灾害对社会动荡影响的大数据定量分析。同时，相关研究也没有分不同地理区域和不同时间尺度进行对比和深入探讨。为解决该问题，本研究对中国三个农业生态区（水稻种植区、小麦种植区和牧业区）开展定量分析，探究公元1470~1911年间中国旱涝灾害与内乱的对应关系。鉴于旱涝与内乱的对应可能是“非线性”和“非固定性”的，我们采用Poisson回归分析和小波一致性分析检测两者关系。结果表明，旱涝灾害诱发了中国历史时期的内乱，但区域差异显著。在水稻种植区，洪涝在年际和数十年际的时间尺度引发内乱；在小麦种植区，洪涝和干旱均在年际和数十年际的时间尺度引发内乱；牧业区的内乱只在数十年际尺度...

The pre-modern history of population change in the Fuping County (Shaanxi Province, China) during the Ming and Qing Dynasties (AD 1368–1911) was reconstructed using historical sources. The Fuping County experienced two major population collapses, i.e. the late Ming Dynasty (1550–1640s) and the 1860–1880s. The first one was caused by the great AD 15...

The observed late twentieth century warming must be assessed in relation to natural long-term variations of the climatic system. Here, we present a Northern Hemisphere (NH) temperature reconstruction for the mid-to-late Holocene of the past 6000 years, based on a synthesis of existing paleo-temperature proxies that are capable of revealing centenni...

Long-term, high-resolution temperature records which combine an unambiguous proxy and precise dating are rare in China. In addition, the societal implications of past temperature change on regional scale have not been sufficiently assessed. Here, based on the modern relationship between chironomids and temperature, we use fossil chironomid assembla...

The ITER bolometer diagnostic will have to provide accurate measurements of the plasma radiation in a varying thermal environment of up to 250 °C. Current fusion experiments perform regular in situ calibration of the sensor properties, assuming stable calibration parameters within short discharge times, e.g. 10 s on ASDEX Upgrade. For long-pulse fu...

Meyer et al. (Reports, 6 January 2017, p. 64) suggest a new chronology for permanent human occupation of Tibet based on their dating of the travertine and colluvium deposits that contain or are deposited near fossil human handprints and footprints. However, misinterpretations in both stratigraphic reconstruction and dating data may have caused the...

Our understanding on the spatial-temporal patterns of climatic variability over the last few millennia in the East Asian monsoon-dominated northern China (NC), and its role at a macro-scale in affecting the prosperity and depression of Chinese dynasties is limited. Quantitative high-resolution, regionally-synthesized palaeoclimatic reconstructions...

China is a traditional agriculture based country and one main region for crop production is southeastern China where temperature is a dominant climate variable affecting agriculture. Temperature and social disturbances both influence crop production, yet distinguishing their relative impacts is difficult due to a lack of reliable, high-resolution h...

Our understanding on the spatial-temporal patterns of climatic variability over the last few millennia in the East Asian monsoon-dominated northern China (NC), and its role at a macro-scale in affecting the prosperity and depression of Chinese dynasties is limited. Quantitative high-resolution, regionally-synthesized palaeoclimatic reconstructions...

Rapid warming has been observed in the high-altitude areas around the globe, but the implications on moisture change are not fully understood. Here we use tree-rings to reveal common moisture change on the southeastern Tibetan Plateau (TP) during the past five centuries, and show that regional moisture change in late spring to early summer (April–J...

Unique agricultural practices engender regional variations in cultural customs, which pave the way for diverse regional migration patterns at discrete geographic levels. In this regard, the long-term fluctuation of land carrying capacity and its association with the frequency and pattern of migration in China at the sub-national level has not been...

A growing body of quantitative (large-N) studies examines the climateeman nexus in historical agrarian China. Their dominant approach is to take the whole of China as a spatial aggregate, without taking into account the role of regional context. Furthermore, quantitative investigations of the climateeman nexus in northwestern (NW) China remain scar...

The Miaodao stratigraphic section (MDS) is located in the Bohai Sea, coastal zone of China, and holds historical information about regional climatic features, sea-level changes, and evolution of the East Asian monsoon. By analyzing the ages of the various sedimentary fascia, combined with proxy paleoclimatic indices [i.e., average grain size (Mz),...

Wendelstein 7-X, a superconducting optimized stellarator built in Greifswald/Germany, started its first plasmas with the last closed flux surface (LCFS) defined by 5 uncooled graphite limiters in December 2015. At the end of the 10 weeks long experimental campaign (OP1.1) more than 20 independent diagnostic systems were in operation, allowing detai...

Recently, the desiccation effect of the North Atlantic Oscillation (NAO) is found to be positively correlated with violent conflict in pre-industrial Europe, with agricultural shrinkage and its subsequent economic shocks to be their causal link. However, it remains unexplored whether the correlation persists if the study period is extended backward...

Effective adaptation determines agricultural vulnerability to climate change, especially in the pre-industrial era. Crop management as an agricultural adaptation to climate change in recent human history, however, has rarely been systematically evaluated. Using Europe as our study area, we statistically compared yield ratio of wheat, rye, barley, a...

Climate change has been statistically proven to substantially influence the economy of early modern Europe, particularly in the long term. However, a detailed analysis of climate change and the economy of historical China remains lacking, particularly from a large-scale and quantitative perspective. This study quantitatively analyzes the relationsh...

The 1600 AD Huaynaputina eruption in Peru was one of the largest volcanic eruptions in history over the past 2000 years. This study operated on the hypothesis that this event dramatically affected the weather and environment in China and the Korean Peninsula. Over the course of this research the Chinese and Korean historical literatures as well as...

Dust storms in northern China strongly affect the living and health of people there and the dusts could travel a full circle of the globe in a short time. Historically, more frequent dust storms occurred during cool periods, particularly the Little Ice Age (LIA), generally attributed to the strengthened Siberian High. However, limited by chronologi...

Wendelstein 7-X (W7-X) is a large optimized stellarator (B=2.5T, V=30m(3)) aiming at demonstrating the reactor relevance of the optimized stellarators. In 2015 W7-X will begin its first operation phase (OP1.1) with five inertially cooled inboard limiters made of graphite. Assuming the heat loads can be spread out evenly between the limiters, 1 seco...

A particular river-whiting phenomenon occurred in the early 2000s in the Xiaoche River and since then it has been reoccurring from June to November each year. Residents were surprised by this phenomenon and worried about it. This study was designed to reveal the forming mechanism of the river-whiting phenomenon. A comparison of T, EC, ORP, DO, TDS...

Recent paleo-climatic/environmental studies have resulted in several high-resolution paleo-precipitation/moisture reconstructions in Northwestern (NW) China over extended periods. Nevertheless, those reconstructions are mostly about the climatic history of individual sites, while fine-grained portrayal and analysis of the geographic extent of droug...

There has been a surge of paleo-climatic/environmental studies of Northwestern China (NW China), a region characterized by a diverse assortment of hydro-climatic systems. Their common approach, however, focuses on "deducing regional resemblance" rather than "exploring regional variance." To date, efforts to produce a quantitative assessment of long...

Bolometers in current and future fusion devices, in particular those in ITER, are vulnerable to stray radiation from electron cyclotron resonance heating (ECRH) which results in measurement errors for plasma radiation detection. To protect the detectors from this stray radiation in the millimetre wavelength range, dedicated diagnostic components ha...

The relationship between climate change and the macroeconomy in pre-industrial Europe has attracted considerable attention in recent years. This study follows the combined paradigms of evolutionary economics and ecological economics, in which wavelet analysis (spectrum analysis and coherence analysis) is applied as the first attempt to examine the...

A climate-crisis relationship has long been conceived: Ellsworth Huntington’s (1907) The Pulse of Asia: A Journey in Central Asia Illustrating the Geographic Basis of History is believed to be the first scholarly work mentioning the climate-crisis relationship.1 Unfortunately, research in this area stagnated after Huntington. The stagnation was, in...

We investigated the mechanism of epidemics with the impacts of climate change and socio-economic fluctuations in the Ming and Qing Dynasties in China (AD 1368-1901). Using long-term and high-quality datasets, this study is the first quantitative research that verifies the 'climate change → economy → epidemics' mechanism in historical China by stati...

The effectiveness of agricultural adaptation determines the vulnerability of this sector to climate change, particularly during the preindustrial era. However, this effectiveness has rarely been quantitatively evaluated, specifically at a large spatial and long-term scale. The present study covers this case of preindustrial society in AD 1500-1800....

It has been demonstrated in recent studies by that wars occurred with greater frequency in Europe in periods of cold climate over the past millennium, and food scarcity is the explanation. However, the issue of whether the climate-war relationship holds consistently across the European continent has been insufficiently explored. In the present stud...

The MGS2 segment of the Milanggouwan stratigraphical section in China's Salawusu River Valley records 5.5 sedimentary cycles consisting of dune sands alternating with fluviolacustrine facies or/and palaeosols. The high Rb and Sr contents and low Rb/Sr ratios in the fluviolacustrine facies indicate the presence of a warm and humid climate, and vice...

An overview of the diagnostics which are essential for the first operational phase of Wendelstein 7-X and the set of diagnostics expected to be ready for operation at this time are presented. The ongoing investigations of how to cope with high levels of stray Electron Cyclotron Resonance Heating (ECRH) radiation in the ultraviolet (UV)/visible/infr...

AimThe long-term cyclical patterns of China's geopolitical shifts are of great interest to scholars and the public, but to date there has been no satisfactory explanation for the alternating occupancy patterns of the country's pastoral and agrarian polities. We fill this gap by differentiating the agroecological settings of these polities over time...

Subject to the unique physical setting of northwestern China (NW China), precipitation in the region is characterized by salient regional differences. Yet, the long-term regional precipitation disparity in NW China still remains insufficiently-explored. In the present study, we base on historical documentation to reconstruct the precipitation indic...

We investigated the relationship between a 2000-year history of nomadic migration and climate change in historical China. By using updated data and statistical methods, the study solved several unanswered questions from past research about the relationship between climate change and the nomadic migration, especially over the long term and on a larg...

Climate change has been proven to be the ultimate cause of social crisis in pre-industrial Europe at a large scale. However, detailed analyses on climate change and macro-economic cycles in the pre-industrial era remain lacking, especially within different temporal scales. Therefore, fine-grained, paleo-climate, and economic data were employed with...

The Bohai Sea coastal zone of China faces the Pacific Ocean to the east and the Eurasian continent to the west; hence, this region is influenced by both the ocean and continental landmasses. The Bohai Sea coastal zone has significant monsoon climate characteristics and a strong sensitivity to climate change. The Miaodao stratigraphical section (MDS...

The next step in the Wendelstein stellarator line is the large superconducting device Wendelstein 7-X, currently under construction in Greifswald, Germany. Steady-state operation is an intrinsic feature of stellarators, and one key element of the Wendelstein 7-X mission is to demonstrate steady-state operation under plasma conditions relevant for a...