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Gannan Prefecture, China faces problems of water resource shortage and fragile ecological environment. Exploring the spatiotemporal pattern of ET can provide a basis for regional water resource development. The study analyzes the interannual changes and spatiotemporal characteristics of evapotranspiration based on MOD16, and selects meteorological, LULC data to analyze their impact on ET through trend analysis method and correlation. From 2000 to 2020, the overall AET in Gannan Prefecture showed an upward trend (P < 0.01), with an average upward rate of 6.30 mm/a. The PET showed a downward trend (P < 0.01), with an average downward rate of 6.24 mm/a. The average change rate of AET in Gannan Prefecture is 6.54 mm/a, mainly concentrated in 5-10 mm/a, and the average change rate of PET is -7.24 mm/a. The AET in Gannan Prefecture is consistent with the interannual change trend of hydrothermal conditions, showing a slow upward trend. The correlation coefficient between AET and rainfall is 0.56, and the correlation coefficient with temperature is 0.69, indicating that the AET in Gannan Prefecture is jointly affected by hydrothermal conditions. The difference in AET between grassland, cultivated land, and wetland in Gannan Prefecture is not significant, and the difference in PET is not significant. Land use type is not the dominant factor for ET changes in Gannan. [ABSTRACT FROM AUTHOR]

Previous multi-proxy records have revealed the advantages of well-preserved and long-scale geological archives from the lake sediments of Barkol Lake, which is located at northeast Xinjiang in northwest China. However, the exact organic matter (OM) sources in the sediments and their response to climatic variability still remain unclear in this area. In this study, we present an 8.8 kyr n-alkane record extracted from the sediments in Barkol Lake to explore the OM sources and the relationship between n-alkanes and climatic changes. The results indicate that the n-alkane composition was dominated by long-chain n-alkanes(C27–C31), implying a dominant origination of OM from the terrestrial higher plants and emergent aquatic plants. The n-alkane data further revealed that changes in OM sources were related to the surface erosion-transportation-deposition processes controlled by climatic changes. Lake level changes, which are also regulated by climate conditions, played an important role in impacting OM accumulation. Relatively wetter conditions would result in a rising lake level that favored more aquatic OM and less terrestrial OM input, and vice versa. The regional climate patterns have been generally dominated by alternations of cold-wet and warm-dry episodes over the past ~8.8 kyr. We preliminarily concluded the dynamic changes of OM input and the hydrological changes in Barkol Lake was mainly controlled by SSTs in the North Atlantic region and melting water supply modulated by Eurasian ice sheet. [ABSTRACT FROM AUTHOR]

Graphium sarpedon is a significant foliar pest of Laurel plants in China. In this study, the MaxEnt model was used to investigate the distribution of G. sarpedon and predict its potential distribution areas in China in the future (2050s and 2090s) based on three Shared Socioeconomic Pathways (SSP1‐2.6, SSP2‐4.5, and SSP5‐8.5), and key environmental variables affecting its distribution were identified. The results showed that under the current climatic conditions, the suitable distribution areas of G. sarpedon were 92.17°–134.96° E and 18.04°–33.61° N, including Yangtze Plain (Middle and Lower), Pearl River Delta, Yangtze River Delta, and Lingnan areas. Under the future climate conditions, the total suitable distribution area of G. sarpedon decreased, but the area of medium suitable area increased. The study identified 11 key environmental variables affecting the distribution of G. sarpedon, the most critical of which was Precipitation of Warmest Quarter (bio18) and precipitation in April, May, June, and September (prec4, prec5, prec6, and prec9). This study is beneficial for monitoring and preventing the possible changes of G. sarpedon and provides theoretical references for its prevention and control. [ABSTRACT FROM AUTHOR]

Droughts are one of the most frequent and destructive natural disasters worldwide. In the past decades, drought events in China are frequent and caused severe socio‐economic losses. To better predict and manage droughts, the spatiotemporal characteristics of the three types of droughts and propagation time (PT) from meteorological to agricultural and hydrological droughts in China during 1982–2014 were analyzed based on drought indices, while the causes of drought propagation were discussed. The results showed that meteorological droughts exhibited an insignificant trend. Agricultural droughts mainly aggravated in the northeastern and central regions. And the hydrological droughts were long‐lasting and exacerbated in most areas. The propagation speed from meteorological to agricultural and hydrological droughts was extremely rapid (1–2 months) in southeast China, and the relationships among droughts were close (correlation coefficient/R > 0.6). The propagation from meteorological to hydrological droughts was slower (6–8 months) in central China. In northwest China, the association between meteorological and hydrological droughts was weak (R < 0.4). Climatic conditions (especially temperature) played a dominant role in the propagation from meteorological to agricultural and hydrological droughts, explaining 63.3% and 52.6% of the variations in the PT, respectively. Urbanization, agricultural activities, elevation, and vegetation contributed to the propagation from meteorological to agricultural droughts. Reservoirs, agricultural activities, and vegetation also affected the propagation from meteorological to hydrological droughts by regulating hydrological processes. These findings are of vital significance to the prediction, warning, and management of different droughts. Plain Language Summary: With climate change and increased water demand caused by population growth, the risk of global drought events has increased dramatically. It is indispensable to understand the mechanism of drought development and monitor drought events accurately. However, there is a lack of research on the systematic and quantitative evaluation of the driving forces of drought propagation across entire China. In this study, drought propagation has been discussed from both qualitative and quantitative perspectives based on several crucial factors (climatic conditions, human activities, and catchment characteristics). Results showed that drought propagation witnessed intensive spatial heterogeneity in China. The propagation from meteorological to agricultural and hydrological droughts was exceedingly rapid (1–2 months) in southeast China, and the relationships among droughts were close. The propagation from meteorological to hydrological droughts was slower (6–8 months) in central China. In northwest China, the connection between meteorological and hydrological droughts was weak (R < 0.4). Climatic conditions played a dominant role in the propagation from meteorological to agricultural and hydrological droughts, explaining the variations of 63.3% and 52.6% in the propagation time, respectively. These findings are of vital significance to the prediction, warning, and management of different types of droughts. Key Points: The spatiotemporal characteristics of different types of droughts in each sub‐region exhibited expected high spatial heterogeneityThe drought propagation time was shorter and the relationship between droughts was closer in southeast China than in northwest ChinaClimatic conditions played a dominant role in the propagation from meteorological to agricultural and hydrological droughts [ABSTRACT FROM AUTHOR]

In order to further understand types of peanut diseases in field, the regularity of main diseases and influencing factors in northern Henan province, accurately prevent and control the field diseases during peanut growth period, in this study, peanut diseases in field were investigated in the field plots including the spring sowing continuous cropping(winter fallow) and peanut wheat rotation fields in Nanzhaoshi village, Datun township, Puyangcity from 2019 to 2021. The occurrence regularity of the main diseases was analyzed, and the influencing factors were studied. The investigation found that the diseases at the early stage of peanut growth were mainly stem rot, early leaf spot and scorch spot and so on, the diseases in at the late stage of growth were mainly early leaf spot, late leaf spot, web blotch, southern blight, and so on. Among them, leaf spot disease was a serious disease that occurred every year during the growth of peanut in the tested field. The correlation analysis results showed that the correlations between the disease index of leaf spot and the average relative humidity of ten days as well as average value of average temperature of ten days were 0.373, -0.311, respectively, reached the extremely significant and significant levels, respectively, indicating that the temperature and the relative humidity had significant and extremely significant impacts on the occurrence of leaf spot. From the results of general linear models univariate analysis, the effects of tillage methods, years, and their interaction on the occurrence of leaf spot disease were not significant, the continuous cropping effect and accumulation of pathogenic bacteria in different years were not obvious. With the advance of growth period, the incidence of leaf spot disease increased, which may be related to the peanut leaf spot disease mainly caused by late leaf spot disease in northern China, as well as the accumulation and repeated infection of leaf spot pathogens in the fields in the year. This study clarified the types, occurrence regularity, and influencing factors of peanut field diseases in northern Henan, and provided a theoretical basis for targeted disease prevention and control. [ABSTRACT FROM AUTHOR]

Cinnamomum cassia Presl. is a subtropical plant that is used for food and medicine. Climate change has changed the suitable habitats of medicinal plants, which might have repercussions for the efficacy of herbal remedies. In this study, the potential distribution in each period of Cinnamomum cassia was predicted and the quality in different suitable habitats was evaluated. According to the results, (1) precipitation, temperature, and soil are the primary environmental variables influencing C. cassia distribution. (2) The high-suitable habitats of current climate scenarios were predominantly located in the southern regions (Guangdong and Guangxi etc.) of China, with an area of 706,129.08 km 2 . Under future climate scenarios, suitable habitats will increasingly move northward, with a greater concentration south of the Yangtze River, particularly in the 2090s SSP585 scenario, the total area of newly extended suitable habitat reaches 312,963.53 km 2 . (3) HPLC and FTIR, combined with chemometrics, can be effective methods for identifying different suitable habitats of C. cassia. The content of trans-cinnamaldehyde (0.85%) is significantly higher in the high suitability habitat compared to the medium-low suitability habitat (0.30%). Our findings can offer valuable guidance for the identification of suitable C. cassia cultivation areas in China, as well as for the evaluation of C. cassia resource quality and the rational use of resources in different suitable habitats., (© 2024. The Author(s).)

In order to evaluate the effects of climatic conditions on maize grain yield (GY), kernel weight (KW), and kernel filling and identify the optimal climatic factors for GY and KW, 2-year field experiments in three seasons, i.e., spring (SPM), summer (SUM), and autumn (AUM), on maize were conducted in Central China. The results showed that SUM had more growing degree days (GDDs) than SPM and AUM due to the higher mean temperature (MT), and also resulted in higher temperature stress (killing degree days (KDDs)) in maize growth duration. Meanwhile, after silking, SPM and SUM had more GDDs and KDDs than AUM because of the higher MT, and the accumulated solar radiation (Ra) for SUM was significantly higher than for SPM and AUM. The GY of SPM was significantly higher than that of SUM and AUM, while SUM's GY was always the lowest, because the GDDGD, MTGD, and KDDGD played significantly negative roles on GY. The final KW for SUM was always the lowest, with GDD, MT, KDD, and Ra causing significantly negative effects, and M△T and precipitation having significant positive effects, resulting in a lower kernel filling rate during the linear kernel filling period (KFRlkf) and a lower GDD at the maximum kernel filling rate (GDDKFRmax). Maize KFRlkf has significant negative linear dependences on GDD, MT, and Ra. In summary, because of the higher MT, KDD, and GDD during maize growth and kernel filling duration negatively affecting the maize kernel filling rate, the GY and KW for SPM were the highest, and for SUM, they were the lowest; therefore, farmers should plant SPM first and then AUM in Central China. [ABSTRACT FROM AUTHOR]

The development of urbanization and the establishment of metropolitan areas causes the urban heat island to cross the original single-city scale and form a regional heat island (RHI) with a larger influence range. Due to the decreasing distance between cities, there is an urgent need to reevaluate RHI for urban agglomerations, considering all cities instead of a conventional single-city perspective. The impact of climatic conditions and human factors on heat islands still lacks a general method and framework for systematic evaluation. Therefore, we used land and night light data as background conditions to study the diurnal and seasonal changes of heat islands in the Zhengzhou metropolitan area, China. Pearson correlation analysis and random forest regression analysis were then used to explore the influence of climatic conditions and human factors on RHI and its internal relationship. We found that the daytime RHI had strong spatial heterogeneity and seasonal differences from 2001 to 2020. The daytime RHI was stronger than nighttime in spring, summer, and autumn, and the nighttime RHI was stronger than daytime in winter. From spring to winter, RHI increased first and then decreased during the daytime, while the opposite was observed at night. In this study, temperature has a greater effect on daytime RHI; CO 2 and NL have a greater effect on nighttime RHI. There was strong spatial heterogeneity in the effects of climatic conditions and human factors on the RHI, with climatic conditions contributing more to the daytime RHI in the northern mountainous areas, while human factors had a greater impact on the nighttime RHI in the main urban areas of each location. The results of this study highlight more targeted and informed strategies for RHI mitigation in the Zhengzhou metropolitan area and provide helpful insights into RHI evaluation in other urban agglomerations. [Display omitted] • The daytime and nighttime RHI showed opposite seasonal trends. • Temperature has a greater effect on daytime RHI; CO 2 and NL have a greater effect on nighttime RHI. • Climate has a large impact on daytime RHI in the northern mountainous area. • Human factor has a large impact on nighttime RHI in the main urban areas. [ABSTRACT FROM AUTHOR]

The study of activity patterns is important for understanding the capacity of animals for adapting their behavior based on their habitat conditions. Among bears, daily activity patterns are considered to be strongly influenced by regional climate conditions. We monitored the activity patterns (active vs. inactive) of the Asiatic black bear (Ursus thibetanus) using infrared camera traps (from May 2013 to November 2016) in the Qinling Mountains, China. We used 125 photos, with 19,132 camera days from 55 camera locations. Based on relative independent capture (RIC), bears were found to be intensively active during June (5.86 ± 1.05 SE), July (8.45 ± 2.74), September (14.83 ± 6.13), and October (8.70 ± 3.43), with activity levels gradually decreasing beyond October. After this decline, activities eventually come to a halt when the bears enter in hibernation. We found that their hibernation period was shorter in the Qinling bears, with only 3 months of denning from January to March. Based on their daily patterns, bears were predominantly active during the daytime both in spring (70.83 ± 35.41%) and summer (52.09 ± 28.89%), but more active at twilight during autumn (51.12 ± 42.88%). We assumed that food preferences and food availability (due to warmer regional climatic conditions) might be responsible for such deviations in daily and monthly activity patterns. [ABSTRACT FROM AUTHOR]

A 15400-year mercury (Hg) accumulation history was reconstructed from a lake sediment core collected from Daping Swamp in western Nanling Mountains, South China. Our results show that the natural input of Hg was deeply influenced by varying climatic conditions. Under wet and warm conditions, increased surface soil organic matter induced by improved vegetation conditions favor an increased input of surface soil-bound Hg to the lake, thus leading to higher Hg accumulation rate, and on the other hand, the direct atmospheric wet deposition of Hg into the lake would also be enhanced. In contrast, under relatively cold and dry conditions, it would display an inverse picture. The signal of anthropogenic influence possibly derived from regional Hg pollution likely started at ~ 3400 cal. years BP, roughly corresponding to the early stage of the Shang Dynasty in Chinese history. Four periods of increased anthropogenic Hg inputs appeared in ~ 3358–2170, ~ 2170–1730, ~ 1369–1043, and especially ~ 600–250 cal. years BP, corresponded to the Shang and Zhou, the Qin and Han, the Sui and Tang, and the Ming and Qing dynasties in China, respectively. A clearly weakened anthropogenic input occurred between~1750 and 1400 cal. years BP, coinciding with the Three Kingdoms to the Southern and Northern Dynasties. Our results revealed the history of the natural Hg accumulation since the Last Deglacial period, and the existence of regional atmospheric Hg induced from anthropogenic activity spanning the last ~ 3400 years. [ABSTRACT FROM AUTHOR]

Forest fire characteristics and their determinants are important considerations for forest management. However, the interaction among natural and anthropogenic factors and their impacts on the occurrence and distribution of forest fires in China, a vast country with enormous variation in its environmental and social contexts, has remained a lasting challenge in science and forest management. In this study, ground-based data of forest fires at the county level in China’s forest fire hazards survey (1989–1991) were applied in studying forest fires and five relevant factors: climate, fuel, topography, human activity, and firefighting facilities at national and provincial scales. During the study period, the county-level number of forest fires in China increased with decreasing latitude, and the burnt area was larger in the subtropical region and some counties of Northeast China. Industry fires and recreation fires showed contrasting latitudinal patterns, and cultural fires dominated in North China. Lightning fires constituted less than 1% of forest fires, and dominated in only six counties. Results of a random forest model indicated that spring temperature and forest stocking level were respectively the most critical variables affecting the fire number and burnt area across China, and overall threshold values of mean spring temperature of 15 °C and forest stocking of 500 million were suggested respectively for abrupt changes in fire frequency and burnt area. Climatic conditions generally dominated the variation in human-caused fires, but lightning fires were primarily influenced by fuel load. However, the most important factors for fire features varied substantially at the provincial scale, highlighting the complexity in the roles of climate or fuel conditions and their combinations for fire risk. Our results provided a first ground-based snapshot of forest fire patterns in China at a high spatial resolution, revealed contrasting features of natural- and human-caused forest fires, and highlighted the spatial variation of fire drivers. The potential uncertainty indicated the necessity of long-term monitoring with multiple approaches for better understanding of forest fire activities and optimal practice in forest fire management in China, both at national and provincial scales. [ABSTRACT FROM AUTHOR]

• Changes in groundwater level depth (GLD) across China were investigated. • GLD changes in confined aquifers were larger than those in unconfined aquifers. • GLDs decreased in relatively humid areas due to increased precipitation. • GLDs increased in relatively arid areas due to groundwater abstraction. • GLDs correlated better with GRACE TWSA in relatively arid areas than humid areas. Groundwater provides perennial, ubiquitous and high-quality freshwater supplies for humanity globally. Difficulties in the collection and collation of groundwater records have hindered our understanding of large-scale groundwater dynamics. This study collected groundwater level depth (GLD) records from 909 groundwater wells across China and the spatiotemporal changes in GLD were investigated in unconfined and confined aquifers from 2005 to 2016 nationally. The GLD distributions were highly heterogeneous, with average (standard deviation) GLDs of 11.9 (20.3) and 21.6 (26.4) m in unconfined and confined aquifers, respectively. From 2005 to 2016, the GLDs decreased significantly over the energy-limited region due to increased precipitation but increased significantly over the water-limited region due to high groundwater abstraction. The GLD changes in confined aquifers were larger than those in unconfined aquifers due to the smaller storativity in confined aquifers. The correlations between the GLDs and GRACE total water storage (TWS) anomalies over the water-limited region were higher than those over the energy-limited region, indicating that groundwater storage contributed more to TWS over arid areas than humid areas. This study highlights the increasing groundwater storage in the energy-limited region and the decreasing groundwater storage in the water-limited region, i.e., enhanced regional differences in groundwater resources. The results improve our understanding of groundwater dynamics in different aquifers and climatic conditions and hence advance robust groundwater management and policy development in China. [ABSTRACT FROM AUTHOR]

Climate change has become a global challenge to the economy and society, highlighting the urgent need for effective policy interventions. Green total factor productivity (GTFP) is a sine qua non for an environmental-friendly and sustainable economy. Therefore, this study investigates the causal relationship between the High-Speed Rail (HSR) and GTFP in a panel of 277 Chinese prefecture-level cities observed from 2003 to 2016. Using the Difference-in-Differences (DiD) approach, we demonstrate that the HSR opening has significantly increased urban GTFP. Furthermore, we explore the channels of the observed positive relationship between the HSR opening and urban GTFP. Specifically, we shed light on the mediating role of climatic conditions, air pollution, and factor agglomeration in the relationship between the HSR opening and GTFP. The results show that climatic conditions significantly mediate this relationship. HSR opening leads to lower pollution and more favourable climatic conditions. Improved climatic conditions drive talent gathering, investment gathering, and green technology concentration, which translate into higher GTFP. Government policies that create favourable climatic conditions to attract green investments in human and physical capital and stimulate green innovations can translate into higher GTFP. • 277 Chinese prefecture-level cities observed from 2003 to 2016 • DiD approach applies to examine High-Speed Rail's (HSR) effect on GTFP. • HSR is a sine qua non for GTFP. • Climatic conditions, air pollution, and factor agglomeration mediate the HSR-GTFP nexus. [ABSTRACT FROM AUTHOR]

The Ning-Meng reach of the Yellow River in China is located in a high-latitude area, and river freezes up and breaks up every year, leading to ice flood and disaster. Since the 1990s, due to the rising winter temperatures, river channel shrinkage and impacts of reservoir operation, the river ice regime of the Ning-Meng reach has changed. This paper investigated reservoir operation effect on river ice regime by eliminating the impact of climatic conditions, and the test method could be applied to other rivers, where similar anthropogenic impacts can be suspected to affect the river ice regime. The results show that compared to the statistics when there were no reservoirs, the duration of ice freezing days reduced 8-33 days, and the ice cover thickness was 16-25 cm thinner than that without reservoirs. The average number of ice flood incidents per year decreased from 11.61 to 3.25, and the number of disasters reduced from 1.69 to 1.41. Moreover, the changes induced by reservoirs joint operation may vastly exceed that by single reservoir operation. The smaller is the distance to the upstream reservoir, the more obvious is the impact from the reservoir. [ABSTRACT FROM AUTHOR]

Previous multi-proxy records have revealed the advantages of well-preserved and long-scale geological archives from the lake sediments of Daping swamp in the western Nanling Mountains in South China. However, the exact organic matter (OM) sources in the sediments and their response to climatic variability still remain unclear. In this study, we present a 15.3-kyr n -alkane record extracted from lacustrine sediments in this swamp to explore the OM sources and the relationship between OM input and climatic changes. The results indicated that the n -alkane composition in sediments was dominated by long-chain n -alkanes (C 27 -C 31), implying that the OM mainly originated from the terrestrial higher plants and emergent aquatic plants. The n -alkane data further verified that changes in OM sources were related to the surface erosion-transportation-deposition processes controlled by climatic changes. Lake level change, which was also regulated by climate conditions, played an important role in impacting OM accumulation; warmer and wetter conditions would result in rising lake levels that favored more aquatic OM and less terrestrial OM input, and vice versa. Variability of the Asian summer monsoon intensity regulated by the dynamic variations in low-latitude processes (e.g., solar insolation, intertropical convergence zone, and El Niño/Southern Oscillation), as well as high-latitude processes (e.g., meltwater input in the North Atlantic), was closely related to the OM accumulation in sediments. • A 2.36-m n -alkane records from the subalpine Daping Swamp in western Nanling Mountains (South China) were reported. • n -Alkane proxies revealed the OM source mainly originated from terrestrial higher plants and emergent aquatic plants. • The OM accumulation is closely related to climatic/environmental conditions. • The warm and wet conditions favor increased aquatic/autochthonous and decreased terrestrial/allochthonous OM input, and vice versa. [ABSTRACT FROM AUTHOR]

• Quantitative assessment of the impact and mechanism of ecological restoration on food security in China. • The partial mediating role of cropland intensive use can weaken the negative effect of ecological restoration on food security. • Climatic conditions can play a differential moderating role in the mediating path of cropland intensive use. • The mediating role of cropland intensive use moderated by climatic conditions exhibits obvious regional heterogeneity. • Ecological restoration does not threaten food security in China. Changes in cropland due to ecological restoration can affect the effective supply of food. Combining socio-economic and climate change to build a theoretical framework that integrates ecological restoration (ER), intensive cropland use (ICU), climatic conditions (CCs) and food security (FS). Based on the panel data of Chinese cities at the prefecture level and above from 2000 to 2019, a moderated mediating model is used to investigate the mediating role of ICU in the process of ER affecting FS under the moderation of different CCs such as temperature, precipitation, and sunshine hours, and analyze the regional heterogeneity of this mediating effect. The results find that, ER has a significantly negative impact on FS, but the partial mediating role of ICU could weaken this negative effect. Different CCs can play a significant moderating role in the mediating path of ICU. Among them, precipitation and sunshine hours can moderate both the first and second halves of this mediating path, while temperature only moderates the first half of this mediating path. The degree of mediating role of ICU moderated by different CCs exhibits obvious regional heterogeneity. For areas where the average annual temperature is>0.978 °C and the average annual precipitation is below the 800 mm isoprecipitation line, the moderating role of temperature and precipitation can weaken or even completely offset this negative mediating effect, while sunshine hours can weaken or even offset the negative mediating effect nationwide. The dual role of ICU mediation and CCs moderation can effectively weaken the negative impact of ER on FS. In total, ER does not threaten China's food security. [ABSTRACT FROM AUTHOR]

Fumonisin B1(FB1) and fumonisin B2(FB2) are the most abundant fumonisins (FBs) occurring worldwide in maize, infected mainly byFusarium verticillioidesandF. proliferatum. A total of 307 corn kernel samples were collected from 45 districts of Gansu, Shandong, Ningxia and the Inner Mongolia provinces of the north and northwest China. The samples were analysed for FB1and FB2by high-performance liquid chromatography. The FBs (FB1+ FB2) incidence rate in samples from Gansu, Shandong, Ningxia and Inner Mongolia were 31.5%, 81.1%, 46.2% and 53.6%, respectively. Average FBs concentration was 703 μg/kg and the concentrations ranged from ≤11 to 13,110 μg kg−1. Results were compared with the European Commission (EC) regulation for FB1+ FB2in unprocessed maize for human consumption of 4 mg kg−1. Contamination in 17 samples was higher than these levels. More than 80% of the samples from Liaocheng county, which is located in the Shandong province, were contaminated with FBs, with a mean total FB concentration of 2496 μg/kg. The result was significantly different from that of the Inner Mongolia (1399 μg/kg), Ningxia (373 μg/kg) and Gansu (175 μg/kg). Average exposure to FBs (0.12 μg/kg body weight/day) is within the provisional maximum tolerable daily intake of 2.0 mg/kg of body weight set by the Joint Food and Agriculture Organization and World Health Organization Expert Committee on Food Additives. [ABSTRACT FROM AUTHOR]

The Food and Agriculture Organization has proposed the current version of the Penman–Monteith method (FAO56-PM) as the standard for calculating reference evapotranspiration (ET0); however, high meteorological data requirements limit its application in many areas. There is thus an urgent need to identify the best alternative empirical method to accurately calculate ET0 in regions that lack sufficient meteorological data. In this study, three temperature-based methods and five radiation-based methods were evaluated using ET0 values generated using the FAO56-PM method in 36 agricultural zones in China based on meteorological data from 823 stations, measured between 2011 and 2020. The results showed that the optimal temperature-based method and radiation-based method differed for different agricultural zones, and no one temperature method or radiation method could be suitable for all agricultural zones. The eight empirical methods were regionally calibrated to improve the ET0 calculation accuracy in the different zones. The relationship between the optimal methods and climatic conditions showed that the most reliable empirical method could be selected according to the local annual mean temperature and aridity index. The results provide useful guidance for the selection of reliable empirical ET0 methods in agricultural zones outside China. [ABSTRACT FROM AUTHOR]

The occurrence of droughts has become more frequent, and their intensity has increased in mainland China. With the aim of better understanding the influence of climate background on drought events in this region, we analyzed the role of the drought-related factors and extreme climate in the formation of droughts by investigating the relationship between the drought severity index (denoted as GRACE-DSI) based on the terrestrial water storage changes (TWSCs) derived from Gravity Recovery and Climate Experiment (GRACE) time-variable gravity fields and drought-related factors/extreme climate. The results show that GRACE-DSI was consistent with the self-calibrating Palmer Drought Severity Index in mainland China, especially for the subtropical monsoon climate, with a correlation of 0.72. Precipitation (PPT) and evapotranspiration (ET) are the main factors causing drought events. However, they play different roles under different climate settings. The regions under temperate monsoon climate and subtropical monsoon climate were more impacted by PPT, while ET played a leading role in the regions under temperate continental climate and plateau mountain climate. Moreover, El Niño–Southern Oscillation (ENSO) and North Atlantic Oscillation (NAO) events mainly caused abnormalities in PPT and ET by affecting the strength of monsoons (East Asian and Indian monsoon) and regional highs (Subtropical High, Siberian High, Central Asian High, etc.). As a result, the various affected regions were prone to droughts during ENSO or NAO events, which disturbed the normal operation of atmospheric circulation in different ways. The results of this study are valuable in the efforts to understand the formation mechanism of drought events in mainland China. [ABSTRACT FROM AUTHOR]

Global low-rank coalbed methane(CBM) resources are abundant. The coal seam has large thickness, low gas content and good permeability, which lead to high production. Foreign low-rank CBM accounts for 80% of total production, while China is 1.8%. Based on the study of the resources characteristics, exploration and development progress, geological differences and accumulation models, the conclusions were obtained. Abundant low-rank CBM are mainly found in Jurassic, Cretaceous and Paleogene coal seam in Xinjiang, eastern Inner Mongolia, and Northeast China. The plate tectonic evolution is dominated by extrusion and collision in China, the physical properties of coal seams have deteriorated significantly. Regional dynamic metamorphism and magma contact thermal metamorphism have caused thermogenic gas in Xinjiang and Northeast China, and secondary biogas generated by rainfall or glacial meltwater in mountain fronts, which lead to high gas content. Geological differences result in the deep weathering zone, diversified gas accumulation modes, and low gas production in China. Climatic conditions and tectonic evolution have a significant impact on the accumulation of low-rank CBM, whose characteristics are “freshwater supply gas” and “trap accumulation gas”. The differences of gas generation and accumulation stages will form different characteristics of CBM reservoirs. China's low-rank CBM exploration should focus on certain depth, high salinity water, monocline/syncline confined water retention area or trapped parts such as fault blocks and anticline. [ABSTRACT FROM AUTHOR]

Exploring the relationship between environmental air quality (EAQ) and climatic conditions on a large scale can help better understand the main distribution characteristics and the mechanisms of EAQ in China, which is significant for the implementation of policies of joint prevention and control of regional air pollution. In this study, we used the concentrations of six conventional air pollutants, i.e., carbon monoxide (CO), sulfur dioxide (SO 2 ), nitrogen dioxide (NO 2 ), fine particulate matter (PM 2.5 ), coarse particulate matter (PM 10 ), and ozone (O 3 ), derived from about 1300 monitoring sites in eastern China (EC) from January 2015 to December 2018. Exploiting the grading concentration limit (GB3095-2012) of various pollutants in China, we also calculated the monthly average air quality index (AQI) in EC. The results show that, generally, the EAQ has improved in all seasons in EC from 2015 to 2018. In particular, the concentrations of conventional air pollutants, such as CO, SO 2 , and NO 2 , have been decreasing year by year. However, the concentrations of particulate matter, such as PM 2.5 and PM 10 , have changed little, and the O 3 concentration increased from 2015 to 2018. Empirical mode decomposition (EOF) was used to analyze the major patterns of AQI in EC. The first mode (EOF1) was characterized by a uniform structure in AQI over EC. These phenomena are due to the precipitation variability associated with the East Asian summer monsoon (EASM), referred to as the "summer-winter" pattern. The second EOF mode (EOF2) showed that the AQI over EC is a north-south dipole pattern, which is bound by the Qinling Mountains and Huaihe River (about 35° N). The EOF2 is mainly caused by seasonal variations of the mixed concentration of PM 2.5 and O 3 . Associated with EOF2, the Mongolia-Siberian High influences the AQI variation over northern EC by dominating the low-level winds (10 m and 850 hPa) in autumn and winter, and precipitation affects the AQI variation over southern EC in spring and summer.

This study aimed to assess the long-term fluctuations in water quality and the influence of Yellow River water recharge and climatic condition on the water environmental index of a typical brackish-water lake. This study investigated several surface water quality parameters and their relationships with the water quality index (WQI) and trophic status index (TSI) of Shahu Lake from 2011 to 2018. A health risk assessment was conducted, and the correlations among water recharge, climatic conditions, and the aforementioned elements were determined. Results show that the water quality in this lake went from good to moderate and back to good as reflected in the changes in its WQI values from 2011 to 2018. The relative water quality inferiority of this lake in 2015 and 2016 was attributed to the significant increase in its COD Mn , TP, TN, NH 3 -N, and fluoride (F - ) concentrations during these years. A combination of these parameters could rapidly predict water quality through a stepwise multiple linear regression. During the study period (except in the frozen season), Shahu Lake maintained a eutrophic status every month (especially in July) irrespective of the spatial changes resulting from low secchi depth and high TP. The limiting nutrient of Shahu Lake changed from phosphorus to both nitrogen and phosphorus, especially during summer, due to seasonal variations and exogenous inputs. The lake had an acceptable health risk level, and water recharge both had positive and negative effects on this lake as reflected in the significant decrease or increase in the concentrations of its principal parameters. This condition was also attributed to temperature and precipitation, which resulted in significant TSI variations. The findings of this study provide ways of estimating and forecasting water quality and trophic status and a basis for managing and improving similar brackish-water lakes., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

A total of 125 maize kernel samples were collected from Hebei province in China during 2011-2013 and were analysed for incidence and contamination levels of fumonisins (FB₁ + FB₂) by HPLC with fluorescence detection. The incidence of FBs for all samples was 46.4%. The mean contamination level of FBs for the samples collected in 2013 was 706 μg kg⁻¹, which was higher than the levels in 2012 (429 μg kg⁻¹) and 2011 (250 μg kg⁻¹). All samples, except five, exhibited total FB levels below 4000 μg kg⁻¹, which is the maximum limit as set by the European Commission. The probable daily intakes of FBs (0.04 in 2011; 0.07 in 2012; 0.12 in 2013, expressed as μg kg⁻¹ body weight/day) were all within the provisional maximum tolerable daily intake of 2.0 μg kg⁻¹ of body weight/day as set by the Joint FAO/WHO Expert Committee on Food Additives. Nevertheless, monitoring is needed to prevent and control the potential risk of FB exposure to the consumers.