@article{shapchenkova_kukavskaya_groisman_2024, title={Fire-Induced Changes in Geochemical Elements of Forest Floor in Southern Siberia}, volume={7}, ISSN={["2571-6255"]}, DOI={10.3390/fire7070243}, abstractNote={Wildfires significantly influence the environmental distribution of various elements through their fire-induced input and mobilization, yet little is known about their effects on the forest floor in Siberian forests. The present study evaluated the effects of spring wildfires of various severities on the levels of major and minor (Ca, Al, Fe, S, Mg, K, Na, Mn, P, Ti, Ba, and Sr) trace and ultra-trace (B, Co, Cr, Cu, Ni, Se, V, Zn, Pb, As, La, Sn, Sc, Sb, Be, Bi, Hg, Li, Mo, and Cd) elements in the forest floors of Siberian forests. The forest floor (Oi layer) samples were collected immediately following wildfires in Scots pine (Pinus sylvestris L.), larch (Larix sibirica Ledeb.), spruce (Picea obovata Ledeb.), and birch (Betula pendula Roth) forests. Total concentrations of elements were determined using inductively coupled plasma–optical emission spectroscopy. All fires resulted in a decrease in organic matter content and an increase in mineral material content and pH values in the forest floor. The concentrations of most elements studied in a burned layer of forest floor were statistically significantly higher than in unburned precursors. Sb and Sn showed no statistically significant changes. The forest floor in the birch forest showed a higher increase in mineral material content after the fire and higher levels of most elements studied than the burned coniferous forest floors. Ca was a predominant element in both unburned and burned samples in all forests studied. Our study highlighted the role of wildfires in Siberia in enhancing the levels of geochemical elements in forest floor and the effect of forest type and fire severity on ash characteristics. The increased concentrations of elements represent a potential source of surface water contamination with toxic and eutrophying elements if wildfire ash is transported with overland flow.}, number={7}, journal={FIRE-SWITZERLAND}, author={Shapchenkova, Olga A. and Kukavskaya, Elena A. and Groisman, Pavel Y.}, year={2024}, month={Jul} }
 @article{sinyukovich_georgiadi_groisman_borodin_aslamov_2024, title={The Variation in the Water Level of Lake Baikal and Its Relationship with the Inflow and Outflow}, volume={16}, ISSN={["2073-4441"]}, DOI={10.3390/w16040560}, abstractNote={Lake Baikal is the largest freshwater lake in the world, accounting for about 20% of the world’s fresh surface water. The lake’s outflow to the ocean occurs only via the Angara River, which has several hydroelectric power plants (HPPs) along its watercourse. The first such HPP, Irkutsk HPP, was built in 1956 and is located 60 km from the Angara River’s source. After two years, the backwater from this HPP expanded to the lake shores and began raising the Baikal Lake level. Currently, there is a dynamic balance between the new lake level, the lake inflow from its tributaries, and the Angara River discharge through the Irkutsk HPP. However, both the Angara River discharge and the Baikal Lake level were distorted by the HPP construction. Thus, to understand the changes to the lake basin over the past century, we first needed to estimate naturalized lake levels that would be if no HPP was ever built. This was an important task that allowed (a) the actual impact of global changes on the regional hydrological processes to be estimated and (b) better management of the HPP itself to be provided through future changes. With these objectives in mind, we accumulated multi-year data on the observed levels of Lake Baikal, and components of its water budget (discharge of main tributaries and the Angara River, precipitation, and evaporation). Thereafter, we assessed the temporal patterns and degree of coupling of multi-year and intra-annual changes in the lake’s monthly, seasonal, and annual characteristics. The reconstruction of the average monthly levels of Lake Baikal and the Angara River water discharge after the construction of the Irkutsk HPP was based on the relationship of the fluctuations with the components of the Lake water budget before regulation. As a result, 123-year time series of “conditionally natural” levels of Lake Baikal and the Angara River discharge were reconstructed and statistically analyzed. Our results indicated high inertia in the fluctuations in the lake level. Additionally, we found a century-long tendency of increases in the lake level of about 15 cm per 100 years, and we quantified the low-frequency changes in Lake Baikal’s water levels, the discharge of the Angara River, and the main lake tributaries. An assessment of the impact of the Irkutsk HPP on the multi-year and intra-annual changes in the Lake Baikal water level and the Angara River discharge showed that the restrictions on the discharge through the HPP and the legislative limitations of the Lake Baikal level regime have considerably limited the fluctuations in the lake level. These fluctuations can lead to regulation violations and adverse regimes during low-water or high-water periods.}, number={4}, journal={WATER}, author={Sinyukovich, Valery N. and Georgiadi, Aleksandr G. and Groisman, Pavel Y. and Borodin, Oleg O. and Aslamov, Ilya A.}, year={2024}, month={Feb} }
 @article{danilovich_loginov_groisman_2023, title={Changes of Hydrological Extremes in the Center of Eastern Europe and Their Plausible Causes}, volume={15}, ISSN={["2073-4441"]}, DOI={10.3390/w15162992}, abstractNote={Regional studies of precipitation changes over Europe show that its eastern part is characterized by small changes in annual precipitation and insignificant aridity trends compared to central and southern Europe. However, a frequency analysis over the past 30 years showed statistically significant increasing dryness trends in eastern Europe and an increase in the occurrence of extremely high rainfall as well as prolonged no-rain intervals during the warm season. The largest increase in aridity was observed in the western and central parts of Belarus. During 1990–2020, the frequency of dry periods doubled in all river basins along the Black, Caspian, and Baltic Sea water divide areas of eastern Europe. From 1970 to 1990, there were high streamflow rates during the winter low-flow season. Consequently, over the past 50 years, in spring, we observed here a continued decrease in maximal discharges across all river basins. In summer, we detected a statistically significant increase in the number of days with anticyclonic weather over eastern Europe, a decrease in rainfall duration by 15–20%, an increase in daily precipitation maxima by 20–30%, and an increase in the number of days with a low relative humidity by 1–4 days per decade.}, number={16}, journal={WATER}, author={Danilovich, Irina S. and Loginov, Vladimir F. and Groisman, Pavel Y.}, year={2023}, month={Aug} }
 @article{kukavskaya_shvetsov_buryak_tretyakov_groisman_2023, title={Increasing Fuel Loads, Fire Hazard, and Carbon Emissions from Fires in Central Siberia}, volume={6}, ISSN={["2571-6255"]}, DOI={10.3390/fire6020063}, abstractNote={The vast Angara region, with an area of 13.8 million ha, is located in the southern taiga of central Siberia, Russia. This is one of the most disturbed regions by both fire and logging in northern Asia. We have developed surface and ground fuel-load maps by integrating satellite and ground-based data with respect to the forest-growing conditions and the disturbance of the territory by anthropogenic and natural factors (fires and logging). We found that from 2001 to 2020, fuel loads increased by 8% in the study region, mainly due to a large amount of down woody debris at clearcuts and burned sites. The expansion of the disturbed areas in the Angara region resulted in an increase in natural fire hazards in spring and summer. Annual carbon emissions from fires varied from 0.06 to 6.18 Mt, with summer emissions accounting for more than 95% in extreme fire years and 31–68% in the years of low fire activity. While the trend in the increase in annual carbon emissions from fires is not statistically significant due to its high interannual variability and a large disturbance of the study area, there are significantly increasing trends in mean carbon emissions from fires per unit area (p < 0.005) and decadal means (p < 0.1). In addition, we found significant trends in the increase in emissions released by severe fires (p < 0.005) and by fires in wetter, dark, coniferous (spruce, p < 0.005 and Siberian pine, p < 0.025) forests. This indicates deeper burning and loss of legacy carbon that impacts on the carbon cycle resulting in climate feedback.}, number={2}, journal={FIRE-SWITZERLAND}, author={Kukavskaya, Elena A. A. and Shvetsov, Evgeny G. G. and Buryak, Ludmila V. V. and Tretyakov, Pavel D. D. and Groisman, Pavel Ya.}, year={2023}, month={Feb} }
 @article{tchebakova_parfenova_bazhina_soja_groisman_2022, title={Droughts Are Not the Likely Primary Cause for Abies sibirica and Pinus sibirica Forest Dieback in the South Siberian Mountains}, volume={13}, ISSN={["1999-4907"]}, DOI={10.3390/f13091378}, abstractNote={Background. Since the mid-20th century, massive dieback of coniferous forests has been observed in the temperate and boreal zones across North America and Northern Eurasia. The first hypotheses explaining forest dieback were associated with industrial air pollution (acid rain). At the end of the century, new hypotheses emerged that supported critical climate-induced aridization to explain forest dieback. Many studies were based on the SPEI (Standardized Precipitation Evapotranspiration Index) drought index. Our goals were to investigate if the SPEI drought index was a suitable metric to reflect drought conditions in wet and moist dark-needled forests in the South Siberian Mountains (Mts) and if droughts trigger the dieback of those forests. Methods. We calculated the SPEI drought index, the annual moisture index AMI, potential evapotranspiration PET, and water balance dynamics for the period 1961–2019 for four transects in the South Siberian Mts. where decline/dieback of dark-needled Siberian pine and fir forests were identified in situ. Climate data from nine weather stations located at lower and upper elevations of each transect were used to calculate climatic index dynamics for the 1961–2019 period to identify dry and wet phases of the period. Results. Our findings showed that climatic moisture/dryness indices have rarely gone down to high risk levels during the last 60 years (1961–2019). AMI did not reach the critical limit, 2.25, characteristic of the lower border for the dark-needled taiga. SPEI values < −1.5 represent drought stress conditions for dark-needled conifers at the lower border, and these conditions occurred 3–4 times during the 60-year period. However, the annual water balance stayed positive in those years in wet and moist forests at mid-to-high elevations. Trees are known to survive occasional (1–2) dry years. We found that dark-needled conifer dieback often occurs in wet years with plentiful rain rather than in drought years. We found forest dieback was associated with the westerlies that bring atmospheric pollution from the west at 50–56 N latitudes, where the air masses cross populated regions that have widespread industrial complexes. Conclusions. We concluded that the observed decline of dark-needled conifers at middle-to-high elevations across the South Siberia’s Mts was conditioned by several plausible causes, among which air pollution seems to be more credible, rather than dry climatic conditions, as cited in recent literature. Results are essential for understanding these ecosystems and others as our planet changes. Other causes and mechanisms should be further investigated, which would necessitate creating infrastructure that supports multi-disciplinary, inter-agency teamwork of plant physiologists, foresters, chemists, etc.}, number={9}, journal={FORESTS}, author={Tchebakova, Nadezhda M. and Parfenova, Elena I and Bazhina, Elena V and Soja, Amber J. and Groisman, Pavel Ya}, year={2022}, month={Sep} }
 @article{georgiadi_groisman_2022, title={Long-term changes of water flow, water temperature and heat flux of two largest arctic rivers of European Russia, Northern Dvina and Pechora}, volume={17}, ISSN={["1748-9326"]}, DOI={10.1088/1748-9326/ac82c1}, abstractNote={Abstract
               The phases of long-lasting (more than 10–15 years) increased and decreased water flow, water temperature and heat flux values in the Northern Dvina River and the Pechora River were studied for the observation period from the 1930s to 2020. To distinguish between different phases, statistical homogeneity tests and normalized cumulative deviation curves were used. Generally, the identified phases displayed statistically significant differences between average values of the measured characteristics. During contrasting phases, the general pattern of water temperature during the warm season, water runoff and heat flux in the Northern Dvina and Pechora River Basins differed considerably. The number of the identified phases varied between the studied rivers and ranged from two to four contrasting phases in the Northern Dvina River exceeded those of the Pechora River. Consequently, the duration of the phases also varied quite significantly. The difference in mean values of the hydrological characteristics during the contrasting phases in the Northern Dvina River exceeded those of the Pechora River. The longest phases of increased and decreased heat flux nearly coincide with contrasting periods of water runoff and water temperature. The phases of simultaneous increased or decreased values of all hydrological characteristics were associated with corresponding periods of increased or decreased air temperature (on average for a year and for the open water period) and annual precipitation values. Those long-lasting phases of simultaneously increased or decreased values of river flow, heat flux, and water temperature were associated with changes of the global thermal regime, regional cryosphere variations, and long-term periods of intensification or weakening of the atmospheric circulation over the North Atlantic, characterised by variability in macrocirculation indices such as the North Atlantic Oscillation and Scandinavian circulation pattern.}, number={8}, journal={ENVIRONMENTAL RESEARCH LETTERS}, author={Georgiadi, Aleksander G. and Groisman, Pavel Y.}, year={2022}, month={Aug} }
 @article{hosseini-moghari_sun_tang_groisman_2022, title={Scaling of precipitation extremes with temperature in China's mainland: Evaluation of satellite precipitation data}, volume={606}, ISSN={["1879-2707"]}, DOI={10.1016/j.jhydrol.2021.127391}, abstractNote={• Four types of temperature sampling are compared for scaling precipitation extremes. • The peak structure remains in the extreme precipitation‐temperature relationship. • The IMERG’s extreme daily precipitation scaling rate is close to the observation. • Against expectations, scaling rate of IMERG’s 30-min precipitations is much smaller. This study explores the sensitivity (termed scaling factor, SF) of daily and 30-minute precipitation extremes with several temperature variables, i.e., within-day surface air temperature (SAT) and dew point temperature (DPT), and antecedent SAT and DPT (corresponding to temperatures one day before a precipitation event, denoted as SAT-C and DPT-C) across China’s mainland. To this end, we used observed daily meteorological data from CN05.1 dataset and 30-minute precipitation data from the Integrated Multisatellite Retrievals for the Global Precipitation Measurement (IMERG). Our results reveal a mix of the positive and negative SFs of extreme daily precipitation with SAT across climatic zones, with peak-like structures developing at higher temperatures (between 17 and 24 °C). Although almost all the SFs turn to positive when SAT-C, DPT, and DPT-C are used, a peak structure is observed over some parts of each climate zone, especially in tropical regions. A comparison between the SFs of the full temperature range and the temperature range before peak structure reveals that a single scaling rate is not valid for the entire temperature range. Moreover, the SFs calculated based on the temperature range before the peak structure (for all four types of temperatures) follow better the Clausius-Clapeyron scaling (∼7%/°C) than the SFs of the full temperature range except for the tropical region. Daily SFs based on IMERG data are mostly comparable to CN05.1 results, with discrepancies mainly in tropical and plateau climates (roughly 25% of the study area). However, IMERG’s 30-min precipitation extremes do not rise as much as expected (even decrease in some parts of the country) with increasing temperatures, contrary to common observations reported in previous studies. It suggests that another precipitation dataset is needed for scaling precipitation extremes at a 30-minute scale, at least for China’s mainland.}, journal={JOURNAL OF HYDROLOGY}, author={Hosseini-Moghari, Seyed-Mohammad and Sun, Siao and Tang, Qiuhong and Groisman, Pavel Yakovlevich}, year={2022}, month={Mar} }
 @misc{chen_john_yuan_mack_groisman_allington_wu_fan_beurs_karnieli_et al._2022, title={Sustainability challenges for the social-environmental systems across the Asian Drylands Belt}, volume={17}, ISSN={["1748-9326"]}, DOI={10.1088/1748-9326/ac472f}, abstractNote={Abstract
               This paper synthesizes the contemporary challenges for the sustainability of the social-environmental system (SES) across a geographically, environmentally, and geopolitically diverse region—the Asian Drylands Belt (ADB). This region includes 18 political entities, covering 10.3% of global land area and 30% of total global drylands. At the present time, the ADB is confronted with a unique set of environmental and socioeconomic changes including water shortage-related environmental challenges and dramatic institutional changes since the collapse of the Union of Soviet Socialist Republics. The SES of the ADB is assessed using a conceptual framework rooted in the three pillars of sustainability science: social, economic, and ecological systems. The complex dynamics are explored with biophysical, socioeconomic, institutional, and local context-dependent mechanisms with a focus on institutions and land use and land cover change (LULCC) as important drivers of SES dynamics. This paper also discusses the following five pressing, practical challenges for the sustainability of the ADB SES: (a) reduced water quantity and quality under warming, drying, and escalating extreme events, (b) continued, if not intensifying, geopolitical conflicts, (c) volatile, uncertain, and shifting socioeconomic structures, (d) globalization and cross-country influences, and (e) intensification and shifts in LULCC. To meet the varied challenges across the region, place-based, context-dependent transdisciplinary approaches are needed to focus on the human-environment interactions within and between regional landscapes with explicit consideration of specific forcings and regulatory mechanisms. Future work focused on this region should also assess the role of the following mechanisms that may moderate SES dynamics: socioeconomic regulating mechanisms, biophysical regulating mechanisms, regional and national institutional regulating mechanisms, and localized institutional regulating mechanisms.}, number={2}, journal={ENVIRONMENTAL RESEARCH LETTERS}, author={Chen, Jiquan and John, Ranjeet and Yuan, Jing and Mack, Elizabeth A. and Groisman, Pavel and Allington, Ginger and Wu, Jianguo and Fan, Peilei and Beurs, Kirsten M. and Karnieli, Arnon and et al.}, year={2022}, month={Feb} }
 @article{grebenets_tolmanov_iurov_groisman_2021, title={The problem of storage of solid waste in permafrost}, volume={16}, ISSN={["1748-9326"]}, DOI={10.1088/1748-9326/ac2375}, abstractNote={The specifics of solid waste storage in permafrost were analyzed. The main types of impact of the waste on the natural environment and frozen soils were determined as mechanical, physicochemical, load, and thermal. The research allowed us to define eight main types of waste storage in the permafrost zone, which were different both in terms of waste accumulation and in terms of their impact on the environment in general and the permafrost in particular. These were: industrial waste storage facilities (slag, sludge and tailing dumps, ash dumps); dumps of rock in sites of mining; household waste accumulators; dumps of wood processing waste in the centers of the timber industry; abandoned territories resulting from a decrease in the population of Northern settlements; storage areas for tanks with residues of fuels and lubricants; tank farms for storing petroleum products in settlements and cities of the North; storage areas for contaminated snow exported from built-up areas. Pollution of waste territories and destruction of many ecosystems as a result of waste storage were caused by use of imperfect technologies for the extraction and processing of raw materials, the ‘legacy’ of past years with disregard to the environmental conditions, the lack of special standards for the storage of garbage and by-product industrial materials, undeveloped methods of waste disposal in harsh climatic conditions.}, number={10}, journal={ENVIRONMENTAL RESEARCH LETTERS}, author={Grebenets, Valery I and Tolmanov, Vasily A. and Iurov, Fedor D. and Groisman, Pavel Y.}, year={2021}, month={Oct} }
 @article{danilovich_zhuravlev_kurochkina_groisman_2019, title={The Past and Future Estimates of Climate and Streamflow Changes in the Western Dvina River Basin}, volume={7}, ISSN={["2296-6463"]}, DOI={10.3389/feart.2019.00204}, abstractNote={The study presents an assessment of the recent and projected changes of the middle and upper Western Dvina River runoff and regional climate during the 20th and 21st centuries. For this assessment, we used historical runoff data, the output of EURO-CORDEX consortium calculations for scenarios RCP4.5 and RCP8.5, and hydrological model “Hydrograph”. Analysis of monthly runoff data for the 1945-2015 period revealed positive trends for each of five months from December to April. These trends are statistically significant at the 0.05 level. No significant trends were found for other months. Significant negative trends were established for spring flood peak discharges (from -69 to -88 m3 s-1 per 10 years). Usually, maximum discharges are observed during spring floods. Minimum discharges during winter low-water period were increased by 6 m3 s-1 per 10 years. The annual runoff trend was statistically significant only at the Polotsk gauging station (9.5 m3/s per 10 years). To the end of the current century over the study region, estimates of projected meteorological parameters (air temperature and precipitation) show positive tendencies of air temperature (from 2.4oC to 4.7oC depending on scenario) and precipitation (up to 15-30 mm). Changes of seasonal and annual temperature and precipitation vary depending on the models and scenarios used. The strongest changes were noticed for the RCP8.5 scenario. The greatest changes within each scenario were revealed for the winter and spring seasons. It is projected that during the 2021-2100 period according to both RCP scenarios, annual discharges will not change in the upper part of the Western Dvina River Basin and increase by 10-12% in its lower part. The maximum spring flood discharges in both RCP scenarios are expected to decrease by 25 %. The minimum runoff of winter low-flow period is expected to increase by up to 60-90% above the present long-term mean values.}, journal={FRONTIERS IN EARTH SCIENCE}, author={Danilovich, Irina and Zhuravlev, Sergey and Kurochkina, Lubov and Groisman, Pave}, year={2019}, month={Aug} }
 @article{liu_tang_liu_yang_groisman_leng_ciais_zhang_sun_2019, title={The asymmetric impact of abundant preceding rainfall on heat stress in low latitudes}, volume={14}, ISSN={["1748-9326"]}, DOI={10.1088/1748-9326/ab018a}, abstractNote={In addition to high temperature, high humidity can have significant consequences on thermal comfort of human beings. The co-occurrence of high temperature and high humidity (so-called ‘oppressive hot days’) often results in heat stress events, but the extent to which it is affected by preceding surface moisture has not been fully understood to date. In this study, we examine the relations between preceding 3-month standardized precipitation index (SPI) and the number of hot days indicated by the surface air temperature (NHD-Tx) and the wet-bulb globe temperature (NHD-Wx) that combines both temperature and humidity in the hottest month in low latitudes. Results show that, in contrast with the negative correlations between SPI and NHD-Tx, which are associated with the previously reported precipitation deficit-temperature feedback, significant positive correlations between SPI and NHD-Wx are found in some low latitude areas. The probability of above-average NHD-Wx could be ∼30% higher after wet conditions than that after dry conditions in areas like southern South America, some parts of Africa, and West Asia. Hotspot analyses further show that abundant preceding rainfall has an asymmetric impact on oppressive hot days by favoring more above-average NHD-Wx. Our analyses imply that a local feedback may exist between surface moisture and oppressive hot extremes, via which the unbearable heat stress over some parts of the tropics is modulated, controlled, and/or caused by changes in the preceding near-surface humidity/soil moisture. The spatially heterogeneous patterns of the relations between preceding rainfall and heat stress confirm the precipitation deficit-temperature feedback in many areas and reveal the coexistence of surface moisture-oppressive heat stress in several low latitude areas. We emphasize the necessity of considering both feedbacks for a better understanding of the distinct roles of preceding rainfall in the consequent development of heat stress in low latitudes.}, number={4}, journal={ENVIRONMENTAL RESEARCH LETTERS}, author={Liu, Xingcai and Tang, Qiuhong and Liu, Wenfeng and Yang, Hong and Groisman, Pavel and Leng, Guoyong and Ciais, Philippe and Zhang, Xuejun and Sun, Siao}, year={2019}, month={Apr} }
 @misc{monier_kicklighter_sokolov_zhuang_sokolik_lawford_kappas_paltsev_groisman_2017, title={A review of and perspectives on global change modeling for Northern Eurasia}, volume={12}, ISSN={["1748-9326"]}, DOI={10.1088/1748-9326/aa7aae}, abstractNote={Northern Eurasia is made up of a complex and diverse set of physical, ecological, climatic and human systems, which provide important ecosystem services including the storage of substantial stocks of carbon in its terrestrial ecosystems. At the same time, the region has experienced dramatic climate change, natural disturbances and changes in land management practices over the past century. For these reasons, Northern Eurasia is both a critical region to understand and a complex system with substantial challenges for the modeling community. This review is designed to highlight the state of past and ongoing efforts of the research community to understand and model these environmental, socioeconomic, and climatic changes. We further aim to provide perspectives on the future direction of global change modeling to improve our understanding of the role of Northern Eurasia in the coupled human–Earth system. Modeling efforts have shown that environmental and socioeconomic changes in Northern Eurasia can have major impacts on biodiversity, ecosystems services, environmental sustainability, and the carbon cycle of the region, and beyond. These impacts have the potential to feedback onto and alter the global Earth system. We find that past and ongoing studies have largely focused on specific components of Earth system dynamics and have not systematically examined their feedbacks to the global Earth system and to society. We identify the crucial role of Earth system models in advancing our understanding of feedbacks within the region and with the global system. We further argue for the need for integrated assessment models (IAMs), a suite of models that couple human activity models to Earth system models, which are key to address many emerging issues that require a representation of the coupled human–Earth system.}, number={8}, journal={ENVIRONMENTAL RESEARCH LETTERS}, author={Monier, Erwan and Kicklighter, David W. and Sokolov, Andrei P. and Zhuang, Qianlai and Sokolik, Irina N. and Lawford, Richard and Kappas, Martin and Paltsev, Sergey V. and Groisman, Pavel Ya}, year={2017}, month={Aug} }
 @article{liu_tang_zhang_groisman_sun_lu_li_2017, title={Spatially distinct effects of preceding precipitation on heat stress over eastern China}, volume={12}, ISSN={["1748-9326"]}, DOI={10.1088/1748-9326/aa88f8}, abstractNote={In many terrestrial regions, higher than usual surface temperatures are associated with (or are even induced by) surface moisture deficits. When in the warm season temperatures become anomalously high, their extreme values affect human beings causing heat stress. Besides increased temperature, rising humidity may also have substantial implications for bodily thermal comfort. However, the effects of surface moisture on heat stress, when considering both temperature and humidity, are less known. In this study, the relationship between the number of hot days in July as indicated by the wet-bulb globe temperature and the preceding three months of precipitation was assessed over eastern China. It is found that the probability of occurrence of above the average number of hot days exceeds 0.7 after a preceding precipitation deficit in northeastern China, but is less than 0.3 in southeastern China. Generally, over eastern China, the precipitation in the preceding months is negatively correlated with temperature and positively correlated with specific humidity in July. The combined effects generate a spatially distinct pattern: precipitation deficits in preceding months enhance heat stress in northeastern China while in southern China these deficits are associated with reduction of heat stress. In the south, abundant preceding precipitation tends to increase atmospheric humidity that is instrumental for the increase of heat stress. These results contribute predictive information about the probability of mid-summer heat stress in eastern China a few weeks ahead of its occurrence.}, number={11}, journal={ENVIRONMENTAL RESEARCH LETTERS}, author={Liu, Xingcai and Tang, Qiuhong and Zhang, Xuejun and Groisman, Pavel and Sun, Siao and Lu, Hui and Li, Zhe}, year={2017}, month={Nov} }