Study region: The transboundary Kherlen River Basin, a temperate grassland basin spanning China and Mongolia. Study focus: While recurrent droughts in recent decades have substantially altered global vegetation patterns, how these changes feed back to modulate hydrological processes, particularly hydrological drought, constitutes a critical knowledge gap. A novel Comprehensive index, the Comprehensive Hydrological Drought Assessment Index (CHDAI), was developed to bridge this gap. The CHDAI synthesizes surface runoff, soil moisture, groundwater, and snowmelt to provide a holistic measure of hydrological response. Its utility was demonstrated by characterizing hydrological droughts (2000-2020) in the Kherlen River Basin, The regulatory influence of vegetation dynamics (measured by kNDVI) on drought was then quantified, and the causal pathways through which kNDVI affects the CHDAI were rigorously identified using structural equation modeling (SEM). New hydrological insights: Results reveal a large-scale exacerbation of hydrological drought in the Kherlen River Basin, with 97.15% of its area experiencing a significant drying trend (P < 0.05). This was manifested through increased drought duration (0.26 yr-1), frequency (0.01 yr-1), and intensity (-0.19 yr-1) across 84.42% of the region, in the central and eastern sectors. SEM revealed that vegetation influences hydrological drought through spatially heterogeneous pathways. At the basin scale, kNDVI exhibited a weak negative association with CHDAI, while in the middle and lower reaches, this association became more pronounced, highlighting the spatial complexity of vegetation-hydrology interactions.

This study focuses on the quantitative simulation of the spatiotemporal distribution characteristics of permafrost area, providing scientific value for Mongolian Plateau permafrost dynamics. Understanding the permafrost area of the Mongolian Plateau and accurately predicting future changes in permafrost area are crucial for sustainable environmental development. In this study, ERA5-Land surface temperature (LST) combined with the temperature at the top of permafrost (TTOP) model are used to calculate the annual permafrost area from 1980 to 2024. In addition, this study used the long short-term memory (LSTM) model to predict permafrost area on the Mongolian Plateau from 2025 to 2100. In this study, it is concluded that (1) the study area is not uniformly covered with permafrost, and its distribution is mainly limited to the northern part of the Mongolian Plateau, with a permafrost area of 53.20 & times; 104 km2; (2) the permafrost area is estimated with an accuracy and precision of 0.94 when compared to the baseline value derived from borehole permafrost data; (3) under the CMIP6 three different shared socioeconomic pathway (SSP) 1-2.6, 2-4.5, and 5-8.5 future scenarios, the distribution of permafrost area shows a downward trend. This study provides a theoretical reference for distribution permafrost area in geographical space, which can help achieve the sustainable development of ice and snow resources.

Drought is a common and recurring natural disaster that poses a serious threat to winter wheat in the Huang-Huai-Hai Plain (HHHP), China. However, a comprehensive understanding of drought characteristics across different growth stages of winter wheat remains limited in the HHHP. This study employed a daily-scale agriculture drought index to identify drought events, analyzed the spatiotemporal patterns of drought frequency, duration, intensity, and combined attributes, and elucidated the underlying drivers of drought trends. Results revealed significant spatiotemporal heterogeneity in the characteristics of drought events. In the northern part of the study area, drought events persisted for a longer duration, whereas the southern part was subject to drought events with greater intensity. During the period 1980–2023, drought conditions across the study area showed an overall alleviation trend, yet with pronounced spatial heterogeneity. Drought moderated in the northern part, while aggravated in the southern part. The spatial variability of drought trends was mainly attributed to the impacts of climatic factors on soil moisture. Increased precipitation and reduced evaporation dominated in the northern part of the study area, whereas enhanced evaporation dominated in most southern regions. Furthermore, drought trends varied across different growth stages of winter wheat, with drought alleviation being particularly pronounced during the green-jointing, heading-flowering, and filling-maturity stages. These findings provide valuable insights for optimizing precision agricultural water allocation and climate adaptation strategies to ensure food security in the HHHP.

Gross primary productivity (GPP) is a key carbon flux in the global carbon cycle, and understanding the inhibitory effects of drought on GPP and its underlying mechanisms is crucial for understanding carbon–climate feedback. However, current research has not sufficiently addressed the threshold dynamics and regional differentiation of GPP responses to the synergistic effects of meteorological drought (MD) and soil moisture drought (SD), particularly in the drought-sensitive Mongolian Plateau. This study focuses on the Mongolian Plateau from 1982 to 2021, using the standardized precipitation index (SPI) and standardized soil moisture index (SSI) to characterize MD and SD, respectively. The study combines the three-threshold run theory, cross-wavelet analysis, Spearman correlation analysis, and copula models to systematically investigate the variation characteristics, propagation patterns, and the probability and thresholds for triggering GPP loss under different time scales (monthly, seasonal, semi-annual, and annual). The results show that (1) both types of droughts exhibited significant intensification trends, with SD intensifying at a faster rate (annual scale SSI12 trend: −0.34/10a). The intensification trend strengthened with increasing time scales. MD exhibited high frequency, short duration, and low intensity, while SD showed the opposite characteristics. The most significant aridification occurred in the central region. (2) The average propagation time from MD to SD was 11.22 months. The average response time of GPP to MD was 10.46 months, while the response time to SD was significantly shorter (approximately 2 months on average); the correlation between SSI and GPP was significantly higher than that between SPI and GPP. (3) The conditional probability of triggering mild GPP loss (e.g., <40th percentile) was relatively high for both drought types, and the probability of loss increased as the time scales extended. Compared to MD, SD was more likely to induce severe GPP loss. Additionally, the drought intensity threshold for triggering mild loss was lower (i.e., mild drought could trigger it), while higher drought intensity was required to trigger severe and extreme losses. Therefore, this study provides practical guidance for regional drought early-warning systems and ecosystem adaptive management, while laying an important theoretical foundation for a deeper understanding of drought response mechanisms.

Snow serves as a crucial water source for vegetation growth on the Mongolian Plateau, and its temporal and spatial variations exert profound influences on terrestrial vegetation phenology. In recent years, global climate change has led to significant changes in snow and vegetation start of growing season (SOS). Therefore, it is necessary to study the mechanism of snow cover on vegetation growth and changes on the Mongolian Plateau. The study found that the spatial snow cover fraction (SCF) of the Mongolian Plateau ranged from 50% to 60%, and the snow melt date (SMD) ranged from day of the year (DOY) 88 to 220, mainly concentrated on the northwest Mongolian Plateau mountainous areas. Using different SOS methods to calculate the vegetation SOS distribution map. Vegetation SOS occurs earlier in the eastern part compared to the western part of the Mongolian Plateau. In this study, we assessed spatiotemporal distribution characteristics of snow on the Mongolian Plateau over the period from 2001 to 2023. The results showed that the SOS of the Mongolian Plateau was mainly concentrated on DOY 71-186. The Cox survival analysis model system established SCF and SMD on vegetation SOS. The SCF standard coefficient is 0.06, and the SMD standard coefficient is 0.02. The SOSNDVI coefficient is −0.15, and the SOSNDGI coefficient is −0.096. The results showed that the vegetation SOS process exhibited differential response characteristics to snow driving factors. These research results also highlight the important role of snow in vegetation phenology and emphasize the importance of incorporating the unique effects of vegetation SOS on the Mongolian Plateau.

Beijing's air quality has seen significant enhancements owing to the successful implementation of China's emission control measures. However, air pollution incidents continue to occur, and more attention should be paid to continuous air quality monitoring and control. Here, the PM2.5 and PM10 samples collected during the air pollution days in Beijing in 2022 were analyzed to study the air quality situation and understand the changes in air pollution sources. The average concentration of PM2.5 was 84.3 mu g/m3 and PM10 was 128.7 mu g/m3. NO3-, SO42- and NH4+ were the primary constituents of water-soluble inorganic ions, with concentrations of 18.8 mu g/m3, 7.9 mu g/m3, 7.4 mu g/m3 in PM2.5, and 20.5 mu g/m3, 9.3 mu g/m3, and 8.1 mu g/m3 in PM10. The enrichment factor values for Sn, Sb, and Cd in PM2.5 exceeded 100, indicating severe anthropogenic pollution. Five pollution factors for PM2.5 and PM10 were obtained from the analysis of PMF model: vehicle emissions and dust, industrial emissions, secondary inorganic aerosols, coal combustion, and electronic manufacturing. The highest contributing factors were vehicle emissions and dust (28 % for PM2.5 and 34 % for PM10). According to the health risk assessment, Mn presented a non-carcinogenic risk to humans. Cd, As, Ni, and Cr (VI) showed a low level of carcinogenic risk within the acceptable range. The backward trajectory analysis showed that air masses from nearby cities exhibited stronger pollutant capabilities. Combining the potential source contribution function and concentration weight trajectory diagrams, the main potential source areas of Beijing are in Hebei, Tianjin, Shanxi and Henan.

Drought events are one of the main factors driving changes in grassland ecosystem productivity. This study aims to investigate the spatiotemporal characteristics of drought in Inner Mongolia's grasslands and its impact mechanisms on grassland productivity. The findings show that: (1) From 1992 to 2018, the overall trend in Inner Mongolia's Gross Primary Productivity (GPP) was declined (56.54 %), with a decline rate of 0.364 gC center dot m(-2)center dot a(-1). Among the three grassland types, only desert steppe GPP exhibited an increasing trend. The Standardized Precipitation Evapotranspiration Index (SPEI) exhibited an overall declining trend, covering 95.54 % of the area. (2) The positive correlation between GPP and SPEI in Inner Mongolia's grasslands was the strongest (88.78 %), with a significant positive correlation in 35.44 % of the area. (3) SPEI has a significant positive effect on grassland GPP, with an influence coefficient of 0.203, and it also had significant indirect effects through soil moisture (SM), Vapor Pressure Deficit (VPD), and Normalized Difference Vegetation Index (NDVI). Among different grassland types, the effect of SPEI on meadow and typical steppe GPP gradually weakened, while its influence on desert steppe GPP progressively strengthened. This study provides important theoretical support for the sustainable development of the region's grassland ecosystems.

To mitigate grassland degradation, China has implemented a series of grazing-centered protection policies. However, how different grazing policies regulate grazing intensity to influence the effects of drought on grassland productivity in Inner Mongolia remains underexplored. This study aims to show the contribution of grazing intensity (GI) to the relationship between drought and grassland gross primary productivity (GPP) in Inner Mongolia across different grazing policy periods from 1992 to 2018, and to explore the specific pathways through which GI and drought influence GPP. The results show that in the first phase of grazing policy implementation (2000–2010, GPIP1 period), GI alleviated the negative impact of drought intensity and counts on GPP, whereas in the second phase of grazing policy implementation (2011–2018, GPIP2 period), GI mitigated the negative effects of the Standardized Precipitation Evapotranspiration Index (SPEI) and drought characteristics on GPP. Structural equation modeling results indicate that from the free grazing period (1992–1999, FG period) to the GPIP2 period, the influence of SPEI on GPP first strengthened and then weakened, while the influence of GI on GPP strengthened across different grassland types. These findings confirm changes in grazing strategies have significant implications for the sustainable development of grasslands.

Study regions: Beijing-Tianjin-Hebei (BTH), China Study focus: With climate change and intensified human activities, drought propagation has become more complex, and it is crucial to reveal its spatial and temporal distribution characteristics and driving factors. In this study, we analyzed the meteorological-hydrological drought propagation process in BTH from 1960 to 2020 based on the standardized precipitation index (SPI) and standardized runoff index (SRI). Through the drought propagation identification method and migration model, we identified four drought propagation types and investigated their propagation angles, directions, distances and paths. Meanwhile, the effects of meteorological factors and land use changes on drought propagation were quantified New hydrological insights for the region: Both SPI (0.138/10a) and SRI (0.21/10a) showed a drying trend, with the strongest trend in northern BTH. SPI events were more frequent (>83 events), longer in duration (9.37 months), and less intense than SRI events. We identified 23 drought propagation events, primarily from single SPI to single SRI, with multiple SPI to one or more SRI events becoming more common after 2000. Drought propagation time (DPT) averaged 1 month but increased to 6 months post-2000, while the Drought Propagation Index (DPI) dropped to 1.2. Droughts mainly propagated northward, covering the longest distance (612.14 km). Precipitation and temperature were key factors influencing the distance of propagation (DPdist), while land use/cover changes affected the drought propagation angle (DPA) and time (DPT).

Gross primary productivity（GPP） of vegetation is an important constituent of the terrestrial carbon sinks and is significantly influenced by drought. Understanding the impact of droughts on different types of vegetation GPP provides insight into the spatiotemporal variation of terrestrial carbon sinks, aiding efforts to mitigate the detrimental effects of climate change. In this study, we utilized the precipitation and temperature data from the Climatic Research Unit, the standardized precipitation evapotranspiration index（SPEI）, the standardized precipitation index（SPI）, and the simulated vegetation GPP using the eddy covariance-light use efficiency（EC-LUE） model to analyze the spatiotemporal change of GPP and its response to different drought indices in the Mongolian Plateau during 1982–2018. The main findings indicated that vegetation GPP decreased in 50.53% of the plateau, mainly in its northern and northeastern parts, while it increased in the remaining 49.47% area. Specifically, meadow steppe（78.92%） and deciduous forest（79.46%） witnessed a significant decrease in vegetation GPP, while alpine steppe（75.08%）, cropland（76.27%）, and sandy vegetation（87.88%） recovered well. Warming aridification areas accounted for 71.39% of the affected areas, while 28.53% of the areas underwent severe aridification, mainly located in the south and central regions. Notably, the warming aridification areas of desert steppe（92.68%） and sandy vegetation（90.24%） were significant. Climate warming was found to amplify the sensitivity of coniferous forest, deciduous forest, meadow steppe, and alpine steppe GPP to drought. Additionally, the drought sensitivity of vegetation GPP in the Mongolian Plateau gradually decreased as altitude increased. The cumulative effect of drought on vegetation GPP persisted for 3.00–8.00 months. The findings of this study will improve the understanding of how drought influences vegetation in arid and semi-arid areas.

In the context of the global decline in the capacity of ecosystem services (ESs) to meet increasing human demands, assessing and quantifying ESs is crucial for ecological policy formulation. To address this, our study employs an adjusted land-use matrix method and the patch-generating land-use simulation (PLUS) model for a quantitative analysis of the ES balance in the Beijing–Tianjin–Hebei–Inner Mongolia (JJJM) region from 2000 to 2020, projecting to 2040. Focusing on the JJJM region, a focal area for ecological policy exhibits significant socioeconomic disparities, revealing a synergistic interplay in the ESs balance. Areas with high vegetation cover, like forests and grasslands, demonstrate an elevated ESs balance, with Inner Mongolia having the highest total ESs balance at 71.40. Conversely, highly urbanized areas, such as Beijing and Tianjin, face deficits in the ESs balance, with Tianjin recording the lowest at 17.83. Our results show an upward trend in total ESs balance in the JJJM region (slope: 0.08 year−1). In particular, regulating services are declining (slope: −0.04 year−1), cultural services are increasing (slope: 0.08 year−1), and provisioning services remain relatively stable. Projecting to 2040, our analysis indicates a slight decline in ESs balance, attributed to Inner Mongolia’s urban expansion. This emphasizes the need for industrial transfers and proactive urbanization promotion to enhance ESs balance and support sustainable management and ecological civilization development in the JJJM region.

Ecosystem services (ES) are defined as the benefits of the natural environment that sustain human life. The analyses of the balance of ecosystem services (ES balance) and its driving factors are critical for achieving the region’s sustainable development goals. This study explored the ES balance in the Beijing-Tianjin-Hebei-Inner Mongolia (JJJM) region, considering the region’s rapid urbanization, implementation of ecological restoration projects, and intense agricultural and pastoral activities. It quantified the ES balance on different scales and selected nine natural and anthropogenic driving factors to reveal its spatio-temporal heterogeneity and change characteristics in 2000–2020. The main conclusions were as follows: (1) The ES balance in the JJJM region exhibited a significant spatial differentiation: generally higher in its eastern and northern areas and lower in its western and southern parts; (2) The ES balance in the Beijing-Tianjin-Hebei region showed a general trend of initial increase and subsequent decrease, while Inner Mongolia exhibited a continuous upward trend. High-value areas (>46) and low-value areas (<10) increased significantly. 27.33% of the areas showed a continuous improvement trend, but the overall ES balance was declining at a rate of 0.110–0.166/year; (3) Among natural factors, temperature had the highest explanatory power (0.409) regarding ES balance, while among anthropogenic factors, grazing density had the highest explanatory power (0.311). The interaction between temperature and precipitation is the strongest; (4) During the study period, the explanatory power of anthropogenic factors increased over time, indicating that human activities were exerting a gradually increasing impact on the JJJM region’s ES balance. Overall, this study enhanced spatio-temporal understanding of the driving factors of ES balance differentiation, and offered a scientific basis for ecological policy-making and the development and transition of socio-economic activities, which could prove to be invaluable in promoting the coordinated development of regional ecologies and economies.

Drought has extensive, far-reaching, and long-lasting asymmetric effects on vegetation growth worldwide in the context of global warming. However, to date, few scholars have attempted the systematic quantification of the temporal effects of drought on global vegetation across various vegetation types and diverse climate zones. Addressing this gap, we quantitatively investigated the effects of drought on global vegetation growth under various scenarios, considering lagged and cumulative effects as well as combined effects in the 1982–2018 period. Our investigation was based on long-term net primary productivity (NPP) and two multiple-timescale drought indices: the standardised precipitation index (SPI) and the standardised precipitation and evapotranspiration index (SPEI). Our main findings were the following: (1) SPI and SPEI exhibited lagged effects on 52.08% and 37.05% of global vegetation, leading to average time lags of 2.48 months and 1.76 months, respectively. The cumulative effects of SPI and SPEI were observed in 80.01% and 72.16% of global vegetated areas, respectively, being associated with relatively longer cumulative timescales of 5.60 months and 5.16 months, respectively. (2) Compared to the scenario excluding temporal effects, there were increases in the explanatory powers of SPI and SPEI for variations in vegetation NPP based on the lagged, cumulative, and combined effects of drought: SPI increased by 0.82%, 6.65%, and 6.92%, respectively, whereas SPEI increased by 0.67%, 5.73%, and 6.07%, respectively. The cumulative effects of drought on global vegetation NPP were stronger than the lagged effects in approximately two-thirds (64.95% and 63.52% for SPI and SPEI, respectively) of global vegetated areas. (3) The effects of drought on vegetation NPP varied according to climate zones and vegetation types. Interestingly, vegetation in arid zones was the most sensitive and resilient to drought, as indicated by its rapid response to drought and the longest cumulative timescales. The vegetation NPP in tropical and temperate zones exhibited a relatively stronger response to drought than that in cold and polar zones. The strongest correlation of vegetation NPP with drought occurred in shrubland areas, followed by grassland, cropland, forest, and tundra areas. Moreover, for each vegetation type, the correlations between vegetation NPP and drought differed significantly among most climate zones. (4) The vegetation NPP in warming-induced drought regions displayed a higher correlation to drought than that in non-warming-induced drought regions, with shorter lagged and longer cumulative timescales. Our findings highlight the heterogeneity of the lagged, cumulative, and combined effects of drought across various climate zones and vegetation types; this could enhance our understanding of the coupling relationship between drought and global vegetation.

As an essential state variable of the earth's terrestrial system, soil moisture (SM) is highly significant regarding hydrological processes, agricultural production, land management in response to issues like soil erosion etc. However, the net effects of different environmental factors on the heterogeneity and variations of SM remain unclear, due to the complex interactions between variables. Indeed, investigating such effects in the highly climate-vulnerable Mongolian Plateau is imperative for water resource management and climate change adaptation. In this study, we analyzed the contributions of different environmental factors on the spatial heterogeneity and variations of SM in the Mongolian Plateau between 1982 and 2020, using a geographic detector model (GDM) and a novel nonlinear Granger causality model. The results of the GDM analysis demonstrated that precipitation and vegetation were the main controls relevant to SM heterogeneity, with their explanatory powers (Q statistics of GDM) found to be higher than 0.67. In two breakpoints-one in the early 1990 ' s and another in 2007-SM demonstrated a pattern of increase, then a decrease, subsequently followed by an increase (insignificant decrease in SM at 100-289 cm depth only). Precipitation was identified as the Granger causal of SM variations over 33.39-97.65% of the plateau's vegetated area, leading to the drying up of 40% of its SM. The greatest contribution to SM in 28-289 cm of the plateau was observed as coming from one-month-old precipitation, due to the lag in the manifestation of effects. Further, rising temperatures were found to have an immediate influence (2.73-5.23%) on SM in 14.61-54.90% of the whole plateau's vegetated area, an impact which was relatively high (>14%) in its northeastern wetting zone. Vegetation change posed a relatively weak effect (<2%) on SM over a limited area of the plateau (27.75-35.42%). Although lesser than the impacts of general climate changes, the contributions of climatic extremes could not be neglected, ultimately accounting for up to 10% of SM changes. In summary, this study provides new insights into the individual contributions of various environmental factors on the spatial heterogeneity and variations of SM in the Mongolian Plateau, offering vital information for policymaking regarding climate change mitigation and adaptation, sustainable use of water resources, and ecological restoration for arid and semi-arid region.

Snow is one of the important water sources for vegetation growth in the Mongolian Plateau, and temporal and spatial changes to it have a profound impact on terrestrial vegetation phenology. In recent years, due to global climate change, the snow associated with the different vegetation types of the Mongolian Plateau has changed substantially, and the mechanism of the resulting change in the vegetation growth date needs to be studied. To address this issue, we used the modified Carnegie Ames Stanford Approach (CASA) model was to estimate the start of growing season net primary productivity (SOSNPP) for different types of vegetation over the Mongolian Plateau from 2001 to 2019. An extensive study of the spatial changes in the SOSNPP and the responses reflected by the winter snow cover fraction (SCFWinter), spring snow melting date (SMDSpring), and SOSNPP to influencing factors is of great significance for ecosystem maintenance. We observed: (1) Different vegetation types exhibited similar changes; SCFWinter underwent a significant decrease of −0.2%, and SMDSpring followed a slow downward trend of −0.59 day of the year (DOY)/year for the whole study area. (2) In the Mongolia Plateau, SOSNPP showed a trend of significant decrease of −0.53 DOY/year. (3) The local hydrothermal condition coupling relationship effect on different vegetation types. Spring temperature (TEMSpring) has a direct effect on vegetation SOSNPP, with a path coefficient of −0.09 in the Mongolian Plateau. SCFWinter and SMDSpring were shown through a path analysis to employ different effects on vegetation SOSNPP. SMDSpring has a direct effect on vegetation SOSNPP, with a path coefficient of 0.53. (4) The SMDSpring and PRESpring factors have a significant impact on vegetation SOSNPP, and they account for 21.11% and 21.26% of the whole study area SOSNPP, respectively. This study is expected to promote the examination of the snow phonological parameters of different related vegetation types and theoretical research on SOSNPP.

Murals are one of the important cultural heritages of mankind. The microbial control of murals is an important subject in mural painting conservation. In recent years, electron beam radiation sterilization has attracted more and more attention in the field of cultural relic protection. Murals are immovable cultural relics, so conventional electron beam irradiation equipment can not be used. However, the development of small mobile electron beam irradiation equipment shows the potential of radiation’s application in the sterilization protection of immovable cultural relics such as murals. A feasibility study of radiation sterilization in mural paintings is needed to investigate the effect of sterilization and the influence of sterilization dose on the stability of mural painting pigments and bonding materials. In this paper, the radiation effects of typical bacteria in tomb murals and mineral pigment powder in ancient Chinese paintings were studied in a laboratory. Firstly, aeromonas hydrophila (Aer.h) and penicillium flavigenum (PNC) were selected as representative strains to determine the appropriate sterilization dose for murals. Then, the effects of radiation on seven kinds of ancient Chinese mineral pigments and white calcium carbonate in the ground layer were verified. The results are as follows: the radiation dose of 10 kGy can effectively remove the two typical strains. This sterilization dose will cause a color difference in calcium carbonate and lead white, while other color pigments are essentially stable. Based on the color difference and UV-vis intensities of the four white carbonate samples, the color change in two of them increased with increasing the dose up to 30 kGy, after which signs of saturation began to appear. X-ray diffraction (XRD), Raman spectra, X-ray photoelectron spectroscopy (XPS) and X-ray absorption near edge structure (XANES) spectra showed that the chemical structure of the samples did not change after irradiation. The formation of free radicals in treated samples was confirmed using an electron paramagnetic resonance (EPR) spectrum test. According to all characterization results, the color difference between the four white carbonate samples may be due to the combination of unpaired electrons and defects in the process of electron beam irradiation to form color centers. After forming the color center, the light absorption of the four samples changed. This is a reversible change, but the samples will take a long time to return to their original state. This study focuses on the influence of electron beam radiation on pigment composition, which is a preliminary exploration of whether radiation sterilization can be applied to the protection of ancient Chinese mural paintings, and the experimental results can provide basic data for later application.

Assessment of spring snow cover fraction (SCF) can be valuable for understanding the efficacy of certain Earth system models (ESMs) in simulating the energy exchange between land and atmosphere system, global hydrological cycle and future climate impacts. Here, we provide a comprehensive evaluation of simulated spring SCF from 23 and 20 ESMs participating CMIP5 and CMIP6, against satellite data from National Oceanic and Atmospheric Administration and National Climatic Data Center (NOAA/NCDC) and a long‐term Northern Hemisphere daily 5‐km snow cover extent product (JASMES) over the Northern Hemisphere (NH) and its 13 subregions during the period of 1982–2005 and 2072–2095. Our results show that (a) no model performs consistently better in simulating spring SCF from all aspects (mean annual, long‐term trend and climatological monthly of spring SCF); (b) the mean annual of spring SCF that was simulated by CMIP5 and CMIP6 model simulations was underestimated in most of the NH and overestimated over the Tibetan Plateau and eastern Asia; (c) most of the model simulations showed a stronger reduction trend for mean annual of spring SCF; (d) the climatological monthly variation of spring SCF is reasonably captured by all model simulations, except for overestimation over the TIB and EAS regions, and there is underestimation in other regions; (e) compared to CMIP5, most of the model simulations in CMIP6 exhibit an improved ability to simulate spring SCF across all aspects; (f) we confirm that the multi‐model ensemble mean (MME) is a better way to represent the three aspects of spring SCF than most individual model simulations. Finally, the spring SCF values predicted by models with better simulation abilities over the NH and its 13 subregions under different scenarios show decreasing trends. Specifically, the highest decreasing trend of spring SCF was found under high emission scenarios (RCP8.5 and SSP5‐8.5).

By contributing to what is considered as the world's largest carbon flux, global climate change has been significantly altering terrestrial vegetation gross primary production (GPP) at a global level. Thus, a robust understanding of the main driving factors influencing GPP change is neccessary for increasing terrestrial carbon sequestration potential of a region. In this study, we conduct an analysis of the main driving factors that have influenced GPP change in the Mongolian Plateau in the 1982-2018 period. The results of our analysis indicate that the GPP of the plateau's total vegetated area has witnessed both growth and decline (of 51.16% and 48.48%, respectively) over the past 37 years, with the latter occurring mainly across northern Mongolia and northeastern Inner Mongolia. Water availability, temperature, and solar radiation are deemed the most crucial climatic factors behind GPP change in 51.21%, 15.51%, and 18.63%, respectively, of the plateau's total vegetated area, according to a nonlinear Granger causality test. These three factors also explain up to 31%, 25.20%, and 17.21% of GPP change in 82.78%, 64.23%, and 69.96%, respectively, of the plateau's total vegetated area, as 34.52%, 31.57%, and 48.62% of the total vegetated area affected by the abovementioned driving factors concomitantly exhibit time-lag effects. The average intensity and extent of the effects of extreme climate indices on GPP change are lesser than the effect of general climate change; up to 21.31% and 22.35% of the GPP change can be explained by the extreme precipitation and temperature in 47.41% and 34.33%, respectively, of the plateau's total vegetated area. Moreover, the standardized total effects of this study's structural equation model (SEM) show that precipitation has the greatest impact on the GPP change (0.42), followed by snow water equivalent (SWE) (-0.11), solar radiation (0.08), and soil moisture or near surface temperature (0.07). Overall, our study provides new insights into the effects of the aforementioned driving factors on GPP change in the Mongolian Plateau, which will be helpful in mitigating the adverse effects of future climate change in the region