Jianhui Chen

• PhD
• Professor at Lanzhou University

The evolution of the East Asian summer monsoon (EASM) during the Holocene has long been of significant interest. Knowledge of past EASM variability not only increases our understanding of monsoon dynamics on a long timescale, but it also provides an environmental and climatic background for research into Chinese cultural development. However, the t...

A 1000-year high-resolution (∼10 years) chironomid record from varved sediments of Sugan Lake, Qaidam Basin on the northern Tibetan Plateau, is presented. The chironomid assemblages are mainly composed of the relatively high-saline-water taxa Psectrocladius barbimanus-type and Orthocladius/Cricotopus, and the relatively low-saline-water taxa Procla...

There is a strong chance that 20th century warming will cause differences in precipitation distribution, hydrological cycle and effective moisture changes over the globe. Arid central Asia (ACA), a unique dry-land area whose atmospheric circulation is dominated today by the westerlies, is one of the specific regions that are likely to be strongly i...

Monsoon precipitation over China exhibits large spatial differences. It has been found that a significantly enhanced East Asian summer monsoon (EASM) is characterized by increased rainfall in northern China and by reduced rainfall in southern China, and this relationship occurs on different time scales during the Holocene. This study presents resul...

Central Asia (CA) faces a severe water crisis exemplified by the shrinking Aral Sea. However, little is known about the entire region, particularly the numerous small water bodies that are vulnerable to climate change yet vital for regional sustainability. We examined water bodies as small as 0.0045 km² across CA from 1992 to 2020, identifying 66,2...

Arid West Asia (AWA) is a critical hub of the Silk Road and one of the primary dust source regions in the Northern Hemisphere. Dust storms in AWA emitting substantial dust particles into the atmosphere, significantly influencing air quality, climate change and marine productivity. However, the variability of dust storm activity in this region durin...

Asian drylands encompass Arid Central Asia (ACA) and West Asia (WA), where water vapor transport is consistently governed by the westerlies. Recent research has identified a dipole pattern in Holocene hydroclimate changes between the ACA and WA, challenging previous assumptions of uniform hydroclimate shifts across the westerlies-dominated mid-lati...

Better understanding of the responses of algal biodiversity to multiple pressures, such as climate warming and eutrophication, is a key issue in aquatic ecology. Alpha and beta diversity may have various patterns over temporal scales, especially in the Anthropocene, when external pressures became more multifaceted. However, the limited availability...

Exploring the spatiotemporal differences of hydroclimate variations is crucial for managing future climate change. In the Asian drylands, West Asia (WA) and arid central Asia (ACA) are both climatically dominated by the westerlies and have shown a dipole pattern in precipitation variation during the past several decades. However, it is unclear whet...

The brief history of monitoring nutrient levels in Chinese lake waters limits our understanding of the causes and the long-term trends of their eutrophication and constrains effective lake management. We therefore synthesize nutrient data from lakes in China to reveal the historical changes and project their future trends to 2100 using models. Here...

Arid central Asia (ACA) is dominated by mid-latitude westerlies and characterized by a climate optimum (a relatively humid climate that has supported the development of human culture) in clear contrast with the climate of monsoonal Asia during the Holocene. Significantly, whether the onset of the Holocene Climate Optimum (HCO) had an impact on cult...

Although climate change has convincingly been linked to the evolution of human civilization on different temporal scales, its role in influencing the spatial patterns of ancient civilizations has rarely been investigated. The northward shift of the ancient Silk Road (SR) route from the Tarim Basin (TB) to the Dzungarian Basin during ∼420–850 CE pro...

To investigate the evolution of precipitation over Asian continent in the Holocene and the associated mechanisms, we used a set of simulations of the transient climate evolution over the past 21,000 years (TraCE‐21ka), multimodel results from the Paleoclimate Modeling Intercomparison Project Phase 4 (PMIP4), and proxy records in Asia. The TraCE‐21k...

Central Asia is the world’s largest azonal arid region, with strong seasonal precipitation patterns. Vegetation in this region is relatively sparse and extremely sensitive to climatic changes. However, long-term trends in vegetation in Central Asia are still unclear or even controversial, hindering the assessment of climate change’s impact on regio...

Reconstructing temperature changes along the Silk Road (SR) over the last two millennia can provide insights into past global changes and their impact on the rise and fall of ancient civilizations in this region. Numerous high-quality single-site paleotemperature records have been produced for the eastern part of the SR (mainly for the Xinjiang reg...

The ecological environment of arid central Asia (ACA) is fragile and sensitive to long-term climate change. Recent palaeoclimatological studies have mainly focused on northwestern China, which is located on the eastern side of the region. Holocene palaeoclimate records from the western region of ACA are scarce, thus hindering the exploration of the...

This study examines the interdecadal variation of cold season precipitation in arid West Asia (AWA) from 1960 to 2019 and identifies the underlying physical mechanisms. The results indicate that the precipitation in this region has exhibited significant interdecadal variation over the past 60 years, which is closely related to Interdecadal Pacific...

Anthropogenic emissions have resulted in increases in the atmospheric fluxes of both nutrient and toxic elements. However, the long-term geochemical impacts on lake sediments of deposition activities have not been clearly clarified. We selected two small enclosed lakes in northern China—Gonghai, strongly influenced by anthropogenic activities, and...

During the past two decades there have been numerous studies of Holocene moisture variations in arid central Asia (ACA). However, these available records show contradictory results regarding the long-term trends. Moreover, most hypotheses that have been proposed to reconcile contradictory interpretations have failed to resolve the inconsistencies....

Iran is a hot climate change study area due to the unique geographical location and fragile ecological environment. As an important source of water resources, precipitation is crucial to the ecological environment and socio-economic development in Iran. Therefore, the applicability evaluation of precipitation datasets is the basis for conducting sc...

There is much debate regarding the temporal and spatial pattern of hydroclimate variations on the Tibetan Plateau during the Holocene, focusing especially on the dipolar pattern of precipitation and moisture between the southern and northern regions, on multiple timescales. Modern observations reveal that the δ¹⁸O in precipitation is an integrated...

Understanding the vegetation response to climate change and human activities during the Holocene may help predict the future trajectory of vegetation change. Moreover, in the semi-arid region of northern China, it may also provide a scientific basis for addressing ecological problems and achieving sustainable development goals. Based on 5 AMS ¹⁴C d...

Knowledge of the past interactions between climate and human land use is essential for understanding the possible future relationships between global change and human societies. In this study, we used pollen and other multi-proxy analyses of the sediments from Xingyun Lake in central Yunnan Plateau to reconstruct the history of land use and ecosyst...

Past annual precipitation (Pann) was reconstructed from Holocene pollen spectra extracted from Gonghai Lake by Cheng et al.1 using a subcontinental scale modern pollen dataset (n=1865, mostly covering China and Mongolia) and the modern analogue technique (MAT), and finds an early-Holocene maximum in contrast to previous Pann reconstructions from Ho...

Anthropogenic emissions have resulted in increases in the atmospheric fluxes of both nutrient and toxic elements; However, the long-term geochemical impacts on lake sediments of deposition activities have not been clearly clarified. We selected two small enclosed lakes in northern China—Gonghai, strongly influenced by anthropogenic activities, and...

The southern arid central Asia (SACA, 35.25°–45°N, 46.25°–80°E) is influenced by Mediterranean type of climate with wet cool season. This study analysed the variations of winter precipitation and their mechanisms during 1979–2017. The results suggest the variations of winter precipitation in SACA are influenced by two water vapour pathways, which a...

Central Asia is one of the dustiest regions of the world, although our understanding of its dust activity over time is limited due to the paucity of continuous, high-resolution, geological records with robust chronologies. In this study, we explore the particle size characteristics of an age-constrained high-resolution last glacial loess record in...

Wildfire activity is an important activity in evolution of vegetation and carbon cycling. Whether wet weather will suppress wildfire or promote them by increasing fuel reserves during the Holocene is not clear. We obtained a record of black carbon from a sediment core spanning the last 14.8 kyr from Gonghai Lake, in North China. There is a close re...

Asian dust storms have long been a major environmental concern in China, affecting the lives of about one billion people. However, it is unclear whether the mechanisms responsible for Asian dust storms during the Holocene varied on different timescales, and thus it is unclear whether there was a shift from a natural forcing to an anthropogenic forc...

Knowledge of the paleoclimatic record of the northeastern Tibetan Plateau (NETP) can potentially improve our understanding of the evolution of the Asian summer monsoon (ASM). However, the history of climate change and inferred spatial extent of the ASM on the NETP since the last deglaciation remain unclear. Here, we use several environmental proxie...

Although the pattern of Holocene temperature variations in central Asia is complex, it is clear that temperature played a fundamental role in influencing humidity conditions and regional human activity. We reconstructed temperature changes using Pediastrum species data, verified by clumped isotopes (Δ47), in the carbonates of sediment cores recover...

The nature of Holocene temperature changes is controversial because of the apparent discrepancy between global temperature reconstructions and climate modelling results. Here we present evidence indicating that the discrepancy can be attributed to the combination of seasonal biases in the proxy temperature records and insufficient understanding of...

The northeastern Qinghai‐Tibet Plateau is strongly influenced by the East Asian summer monsoon (EASM), the Indian summer monsoon (ISM) and the westerlies. However, how these various circulation systems interacted in the region during the Holocene, and the nature of the associated environmental impacts, are unclear and even controversial. Here we pr...

Arid Central Asia (ACA) is far from oceanic moisture sources and has a prevailing arid climate; thus the environment of the region is hydroclimatically sensitive. The eastern part of ACA is dominated by the basin-mountain system. A previous study proposed that the humid mountains and the arid basins were characterized by an opposite pattern of clim...

Arid Central Asia (ACA), with its diverse landscapes of high mountains, oases, and deserts, hosted the central routes of the Silk Roads that linked trade centers from East Asia to the eastern Mediterranean. Ecological pockets and ecoclines in ACA are largely determined by local precipitation. However, little research has gone into the effects of hy...

Monsoon boundary zone (MBZ) is a transitional zone between the arid Central Asia (ACA) and humid Asia monsoon area, located in North China‐Mongolia. During boreal summer, both the mid‐latitude westerlies and East Asian Summer monsoon (EASM) play essential roles in the precipitation variations in the MBZ, via causing anomalous cold air mass from the...

Instrumental data indicate the occurrence of a dipolar pattern of precipitation anomalies between north China and the Yangtze River Valley (YRV), which was termed “northern drought (flood)—southern flood (drought)” scenario. It has been shown that this pattern occurred during the Medieval Climate Anomaly (MCA) and the Little Ice Age (LIA). However,...

To make a reliable reconstruction of past climate from soil-surface modern pollen, it is necessary to reduce the sources of error. In this paper, pollen percentages of the sub-continental scale modern pollen-climate dataset from China and Mongolia (with 68% soil-surface samples) are homogenized at various spatial scales. A tailored calibration-set...

Holocene variations in precipitation in central and eastern arid central Asia (ACA) have been widely investigated, but the pattern in western ACA remains unclear. We present records of the stable carbon isotope composition of bulk organic matter (δ¹³Corg), magnetic parameters, and sediment color, from five loess‐paleosol sequences in NE Iran, in we...

During the latter stages of the Holocene, and prior to anthropogenic global warming, the Earth underwent a period of cooling called the neoglacial. The neoglacial is associated with declining summer insolation and changes to Earth's surface albedo. Although impacts varied globally, in China the neoglacial was generally associated with a cooler clim...

The late Holocene is generally regarded as an interval of monsoon recession and decreased precipitation in North China. However, the extent to which this affected the status of lakes in North China is unclear. In the study, we analyzed multiple proxies (δ¹³C, magnetic susceptibility [χlf], and exogenous element concentrations) from Lake Mayinghai,...

The Asian monsoon (AM) played an important role in the dynastic history of China, yet it remains unknown whether AM-mediated shifts in Chinese societies affect earth surface processes to the point of exceeding natural variability. Here, we present a dust storm intensity record dating back to the first unified dynasty of China (the Qin Dynasty, 221–...

The interpretation of trace element/calcium ratios of speleothems as indicators of local hydroclimatic variability in the vicinity of caves has led to controversy in reconstructing the evolution of moisture conditions in arid central Asia (ACA) during the Holocene. Here we present records of Mg/Ca, Sr/Ca, Ba/Ca, and U/Ca from precisely dated stalag...

Abstract. Previous research has indicated that variations in moisture conditions in arid central Asia (ACA) were out-of-phase with those of monsoonal Asia during the Holocene. In order to investigate this phenomenon, we compared the pattern of moisture variations in ACA and the region dominated by the East Asia summer monsoon (EASM) during the last...

Desertification is of pressing environmental concern in large parts of Asia and directly affects millions of people. Arid Central Asia (ACA) in particular is highly sensitive to desertification and environmental change. Climate change in ACA may be driven by westerly circulation or monsoon variation. However, no consensus exists over their relative...

The natural environment provides material essentials for human survival and development. The characteristics, processes, regional differentiation and forcing mechanisms of the elements of the natural environment (e.g. geomorphology, climate, hydrology, soil, etc.) are the main objects of research in physical geography. China has a complex natural e...

During the latter stages of the Holocene, and prior to anthropogenic global warming, the Earth underwent a period of cooling called the neoglacial. The neoglacial was associated with declining summer insolation and changes to Earth surface albedo. Although impacts varied globally, in China the neoglacial was generally associated with cooler, more a...

Climatic instability, especially on decadal to multi-decadal time scales, has a profound impact on societal development and human welfare in semi-arid and arid regions. Previous work suggested that arid northwestern China was characterized by a dry Medieval Warm Period (MWP, from ca. 1000 to 1300 AD) and a wet Little Ice Age (LIA, from ca. 1400 to...

Numerous studies have been conducted on the Holocene climatic evolution of arid central Asia (ACA) using various geological proxies. However, the quality of the age control and the temporal resolution of the proxy records used make it difficult to characterize hydroclimatic changes on centennial to multidecadal timescales. Here we present a stalagm...

State Natural Science Award of China in 2018

The long-term cooling or warming trend is one of the most important aspects of Holocene paleoclimatic research. However, there are currently significant discrepancies among climatic simulation results, sedimentary and synthesized Holocene temperature records. These discrepancies call for new Holocene temperature records with a robust chronology and...

Proxy-based reconstructions of Holocene temperature show that both the timing and magnitude of the thermal maximum varied substantially across different regions. Given the 'Holocene temperature conundrum', it is becoming increasingly important to reconstruct seasonal temperature variations. As a major component of the global monsoon system, the Ind...

Human activities over the last ∼100 years have fundamentally changed the biogeochemistry of the global nitrogen cycle. For example, increased nitrogen deposition from industrial and agricultural sources has been linked to lake acidification and nutrient fertilization, and thus it has the potential to significantly influence lake ecosystems. Records...

Proxy-based reconstructions of Holocene temperature show that both the timing and magnitude of the thermal maximum varied substantially across different regions. Given the 'Holocene temperature conundrum', it is becoming increasingly important to reconstruct seasonal temperature variations. As a major component of the global monsoon system, the Ind...

Changes in global climate intensify the hydrological cycle, directly influence precipitation, evaporation, runoff, and cause the re-distribution of water resources in time and space. The aridity index (AI), defined as the ratio of annual precipitation to annual potential evapotranspiration, is a widely used numerical indicator to quantify the degre...

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...

Alpine lakes not only provide internationally important habitats for endangered species, they also play a crucial role in the regional water balance. Unfortunately, a rapid loss of alpine lakes in China has occurred in recent decades; however, intensive human activities, together with regional differences in the responses of lakes to climate change...

A long-term perspective on the spatial variation of the northern boundary of the East Asian summer monsoon (EASM) and the related physical mechanisms is important for understanding past climate change in Asia and for predicting future changes. However, most of the meteorological definitions of the EASM northern boundary do not correspond well to th...

This study examines the shifts in terrestrial climate regimes using the Köppen–Trewartha (K–T) climate classification by analyzing the Community Earth System Model Last Millennium Ensemble (CESM-LME) simulations for the period 850–2005 and CESM Medium Ensemble (CESM-ME), CESM Large Ensemble (CESM-LE) and CESM with fixed aerosols Medium Ensemble (CE...

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 stability of Earth's critical zone is intimately linked with erosion, weathering and vegetation type and density. Therefore, it affects global biogeochemical processes which in turn affect the global climate by absorbing and reflecting solar radiation, and by altering fluxes of heat, water vapour, carbon dioxide and other trace gases through va...

Traditionally, the evaluation of pollen-based quantitative paleoclimate reconstructions focuses on the ability of calibration sets to infer present climatic conditions and/or the similarity between fossil and modern assemblages. Objective criteria for choosing the most appropriate climate parameter(s) to be reconstructed at a specific site are thus...

Anthropogenic aerosol increases over the past few decades have weakened the Asian summer monsoon 1–3 with potentially far-reaching socioeconomic and ecological repercussions. However, it is unknown how these changes will aaect freshwater ecosystems that are important to densely populated regions of Asia. High-resolution diatom records and other pro...

Climatic and environmental changes in the northeastern Tibetan Plateau are controlled by the Asian summer monsoon (ASM) and the westerlies, two key circulation components of the global climate system which directly affect a large human population and associated ecosystems in eastern Asia. During the past few decades, a series of Holocene palaeoclim...

We investigate chironomid assemblages in a sediment core from Gonghai Lake, which is located on the East Asian summer monsoon (EASM) boundary in northern China, to quantify EASM variability during the past 13.5 ka BP. Six significantly different chironomid assemblage zones indicate that maximum precipitation and water depth occurred in the mid-Holo...

The lacustrine deposits of lakes in arid central Asia (ACA) potentially record palaeoclimatic changes on orbital and suborbital time scales, but such changes are still poorly understood due to the lack of reliable chronologies. Bosten Lake, the largest freshwater inland lake in China, is located in the southern Tianshan Mountains in central ACA. A...

The nature of an Anthropocene has been increasingly discussed and debated in the last two decades, with a focus on the arguments for or against the “Anthropocene” as a geological epoch. Some argue for an onset of Anthropocene between 1945‒1964 AD, when intensive atmospheric nuclear testing resulted in peak values of 14C that is widely recorded in t...

A cal. 20-year-resolution pollen record from Gonghai Lake presented the detailed process of mountain vegetation succession and East Asian Summer Monsoon (EASM) changes since the last deglaciation in Shanxi Province, North China. Modern vegetation distribution and lake surface pollen assemblages suggested that the fossil pollen mainly came from loca...

The reconstruction of variations in effective moisture over the past millennium are important for assessing potential future climatic trends in environmentally-sensitive arid Central Asia (ACA), especially in the context of ongoing global warming. However, high-resolution time series reflecting past moisture variability in the region are scarce, th...