We collected and verified documentary records of the latest spring snowing dates(LSSD)in Hangzhou during Southern Song Dynasty.Furtherly,the statistical correlation between this proxy and February–April mean temperat...We collected and verified documentary records of the latest spring snowing dates(LSSD)in Hangzhou during Southern Song Dynasty.Furtherly,the statistical correlation between this proxy and February–April mean temperature in Hangzhou was examined,and samples later than the perennial mean of the LSSD during Southern Song Dynasty were transformed into the decadal mean of LSSD by means of Boltzmann function.General characteristics of this reconstructed LSSD series with a 10-year temporal resolution was analyzed,and it was also compared with other documentary evidences and reconstructed climate series in China for the period 1131–1270.The results and discussion suggested that:(1)Records of the LSSD in Hangzhou during Southern Song Dynasty did not refer to ice pellets and graupels,which had an explicit climate significance(–0.34℃/10 d,R2=0.37,p<0.001).However,when this proxy is used to reconstruct temperature changes,all dates should be converted into proleptic Gregorian style and meet the same criterion of"true Qi"as the Chinese traditional calendar after 1929.(2)The decadal mean of LSSD can be effectively estimated by using the forefront of LSSD in the decade on the basis of Boltzmann function,whose extrapolation has a lesser uncertainty than those on the basis of linear models or polynomial models.(3)The spring climate in Hangzhou during 1131–1270 was almost as warm as the period 1951–1980.At the centennial scale,this period can be divided into two phases:the cold 1131–1170 and the warm 1171–1270.In the latter,1181–1200 and 1221–1240 were two cold intervals at the multi-decadal scale.(4)The reconstructed LSSD series was consistent well with other documentary evidences and reconstructed climate series in China for 1131–1270,which may reflect the influence on the climate over most regions of China imposed by the Pacific Decadal Oscillation(PDO).展开更多
SINCE December 2025,Urumqi City and Altay Prefecture in northwest China’s Xinjiang Uygur Autonomous Region,and northeast China’s Jilin Province have both entered their snow seasons.The snow holidays(for primary and ...SINCE December 2025,Urumqi City and Altay Prefecture in northwest China’s Xinjiang Uygur Autonomous Region,and northeast China’s Jilin Province have both entered their snow seasons.The snow holidays(for primary and secondary school students)in Urumqi and Altay ran from December 1 to 5.When combined with the preceding and following weekends,the holiday extended to nine days.展开更多
Yiwu merchants ride a winter sports boom as“Made in China”winter gear heats up the global economy.YIWU,located in east China’s Zhejiang Province,is globally renowned as a hub for small commodities.This winter,its s...Yiwu merchants ride a winter sports boom as“Made in China”winter gear heats up the global economy.YIWU,located in east China’s Zhejiang Province,is globally renowned as a hub for small commodities.This winter,its snow and ice sports products are generating a surge in business.Products such as snowboards,ski goggles,and ski poles are drawing an increasing number of merchants worldwide for purchases.展开更多
Tajikistan,a mountainous country and a vital water tower for Central Asia,is becoming increasingly vulnerable to snow drought under climate change,threatening its snow-and glacier-fed streamflow.Yet,the impacts of sno...Tajikistan,a mountainous country and a vital water tower for Central Asia,is becoming increasingly vulnerable to snow drought under climate change,threatening its snow-and glacier-fed streamflow.Yet,the impacts of snow drought on the regional hydrology remain insufficiently understood.In this study,we integrated multisource data,including the Fifth Generation European Centre for Medium-Range Weather Forecasts Atmospheric Reanalysis for Land Applications(ERA5-Land)data and hydrological station data,to systematically assess the snow drought patterns and their impacts on streamflow during 1950–2023.We identified snow drought events based on precipitation and snow fraction anomalies relative to climatological means and classified them into warm snow drought,dry snow drought,and warm&dry snow drought.The results revealed that snow drought was a recurrent phenomenon,occurring in 51.70%of the years during the study period,with warm&dry snow drought accounting for 21.90%of the total events.Both the frequency and severity exhibited pronounced spatial variability,largely governed by the elevation and snowfall fraction.Specifically,the frequency of warm snow drought was negatively correlated with the snowfall fraction,decreasing on average by 0.20 per unit increase in snowfall fraction,whereas the frequency of dry snow drought was positively correlated,increasing by 0.07 per unit increase.The streamflow analysis results demonstrated that snow drought typically reduced the warm-season discharge by 5.00%–18.00%in certain rivers,thereby exacerbating the water stress during the dry season.The results of this study advance our understanding by explicitly linking the types of snow drought to hydrological responses in Central Asia’s high mountains,providing a scientific basis for climate adaptation and sustainable water resource management in Tajikistan.展开更多
China’s winter sports boom creates jobs and spurs economic growth,bringing substantial benefit to the general public,local governments,and businesses.CHINA’s ice and snow economy,riding on the winter sports boom,is ...China’s winter sports boom creates jobs and spurs economic growth,bringing substantial benefit to the general public,local governments,and businesses.CHINA’s ice and snow economy,riding on the winter sports boom,is stimulating consumption across the country,fueling regional development and creating new industrial ecosystems.This trend perfectly matches one of China’s key tasks for 2026.展开更多
How is a nation’s embrace of snow and ice shaping a new cultural identity and igniting a multi-trillion-yuan economic boom?ADRIAAN Smit now cannot imagine a life without snowboarding,a passion that has become central...How is a nation’s embrace of snow and ice shaping a new cultural identity and igniting a multi-trillion-yuan economic boom?ADRIAAN Smit now cannot imagine a life without snowboarding,a passion that has become central to his world.He is excited to witness how winter sports are fostering a new winter culture in China.Listening to Smit speaking so enthusiastically about the slopes,one might assume he was raised in a region where snow sports are a way of life,but the fact is quite the contrary.展开更多
Yiwu merchants ride a winter sports boom as“Made in China”gear heats up the global economy Yiwu,located in east China’s Zhejiang Province,is globally renowned as a hub for small commodities.This winter,its snow and...Yiwu merchants ride a winter sports boom as“Made in China”gear heats up the global economy Yiwu,located in east China’s Zhejiang Province,is globally renowned as a hub for small commodities.This winter,its snow and ice sports products are generating a surge in business.展开更多
Abstract To investigate the use of the three-point bending method and supplement the corresponding strength data of compacted snow for transportation-related applications in cold regions,compacted snow beams with an a...Abstract To investigate the use of the three-point bending method and supplement the corresponding strength data of compacted snow for transportation-related applications in cold regions,compacted snow beams with an average density of 592 kg·m−3 were fabricated and tested at three distinct flexural strain rates.Each strain rate corresponded to the ductile,transitional,and brittle behavior of compacted snow,respectively.The flexural strength,ranging from 0.518 to 0.933 MPa,peaks at the ductile-to-brittle transition,while the flexural modulus,varying between 48.97 and 287.72 MPa,increases with strain rate within the tested range.At the same strain rate corresponding to brittle failure,both mechanical properties of compacted snow exhibit higher values than those of natural snow tested by the authors.Notably,the flexural strain rate at the ductile-to-brittle transition for compacted snow identified in this study is comparable to those previously reported for natural snow under uniaxial tension.Additionally,the obtained strength data are thoroughly compared with existing literature,with detailed discussions provided.The loading rates associated with typical failure modes of compacted snow under bending,together with the obtained strength values,provide methodological guidance and reference data for future in situ testing of compacted snow structures.展开更多
As the wheel of time turns toward the year's end and the beginning of the new year,the snow-kissed land of Xizang gracefully unveils its grandeur and offers a feast of wonders for all to explore.Here,crystalline i...As the wheel of time turns toward the year's end and the beginning of the new year,the snow-kissed land of Xizang gracefully unveils its grandeur and offers a feast of wonders for all to explore.Here,crystalline ice and snow form a celestial winter realm.Amid the biting seasonal winds,o month-long New Year celebration brings one o deep,heartfelt warmth.Rarely witnessed elsewhere in the world,this collection of New Year customs stands as both a cultural marvel and a warm gift that the plateau bestows upon the depths of winter.展开更多
PHOTO NEWS Unforgettable Winter Break Tourists take selfies in front of snow sculptures in the Fenghuang Mountain Scenic Area,Yakeshi City in Inner Mongolia Autonomous Region,on December 7,2025.
China’s winter sports boom is expanding beyond its traditional northern heartlands,fueling a dynamic ice-snow economy and culture nationwide.This seasonal surge is driven by sustained investment and innovative develo...China’s winter sports boom is expanding beyond its traditional northern heartlands,fueling a dynamic ice-snow economy and culture nationwide.This seasonal surge is driven by sustained investment and innovative development models that are turning cold climates into hot economic opportunities.展开更多
The Balkhash Lake Basin(BLB),a vital Central Asian watershed,faces hydrological uncertainty under climate warming.This study integrated multi-source remote sensing data(Sentinel-1 snow depth,Randolph Glacier Inventory...The Balkhash Lake Basin(BLB),a vital Central Asian watershed,faces hydrological uncertainty under climate warming.This study integrated multi-source remote sensing data(Sentinel-1 snow depth,Randolph Glacier Inventory(RGI)v.7.0 glacier inventory,and Advanced Spaceborne Thermal Emission and Reflection Radiometer(ASTER)mass balance)with a degree-day model to reconstruct decadal snow and ice dynamics across 13 sub-basins and analyzed their hydrological impacts from 1950 to 2014.The results showed that:(1)while flows from the downstream river of the BLB decreased from 1950 to 1982 due to land surface changes,runoff increased significantly after 1982 in the Ili River(18.0%)and moderately increased in most rivers in the east(1.3%–8.3%),driven by increased precipitation and glacier melt.Runoff in the Ayaguz catchment(no glaciers with the highest climate warming)declined(10.5%);(2)climate warming reduced precipitation falling as snow caused snow melt water to decline(0.03–0.22 mm/a)across the BLB,leading to downward shifts in runoff and runoff coefficient,especially in the rivers in the east.However,snow melt during April–June positively correlated with runoff coefficient,contributing to an upward shift in the Ili River Basin;and(3)meltwater from glacierized areas(<5.0%of basin area)contributed to 14.3%of total ablation water.Net glacier melt provided substantial excess flows(11.6 m3/s in the Ili River and<1.0 m3/s in the rivers in the east),generally counterbalancing the negative effect of rising potential evaporation at decadal scales and positively correlating with the runoff coefficient.Therefore,water stress in the BLB may be more severe in the future due to the accelerating glacier melt after the abrupt increase in air temperature in 2000,the continuing decline in snow melt,and the significant inter-annual variations in precipitation.展开更多
To address the issue of transient low-voltage instability in AC-DC hybrid power systems following large disturbances,conventional voltage assessment and control strategies typically adopt a sequential“assess-then-act...To address the issue of transient low-voltage instability in AC-DC hybrid power systems following large disturbances,conventional voltage assessment and control strategies typically adopt a sequential“assess-then-act”paradigm,which struggles to simultaneously meet the requirements for both high accuracy and rapid response.This paper proposes a transient voltage assessment and control method based on a hybrid neural network incorporated with an improved snow ablation optimization(ISAO)algorithm.The core innovation of the proposed method lies in constructing an intelligent“physics-informed and neural network-integrated”framework,which achieves the integration of stability assessment and control strategy generation.Firstly,to construct a highly correlated input set,response characteristics reflecting the system’s voltage stable/unstable states are screened.Simultaneously,the transient voltage severity index(TVSI)is introduced as a comprehensive metric to quantify the system’s post-disturbance transient voltage performance.Furthermore,the load bus voltage sensitivity index(LVSI)is defined as the ratio of the voltage change magnitude at a load node(or bus)to the change in the system-level TVSI,thereby pinpointing the response characteristics of critical load nodes.Secondly,both the transient voltage stability assessment result and its corresponding under-voltage load shedding(UVLS)control amount are jointly utilized as the outputs of the response-driven model.Subsequently,the snow ablation optimization(SAO)algorithm is enhanced using a good point set strategy and a Gaussian mutation strategy.This improved algorithm is then employed to optimize the key hyperparameters of the hybrid neural network.Finally,the superiority of the proposed method is validated on a modified CEPRI-36 system and an actual power grid case.Comparisons with various artificial intelligence methods demonstrate its significant advantages in model speed and accuracy.Additionally,when compared to traditional emergency control schemes and UVLS strategies,the proposed method exhibits exceptional rapidness and real-time capability in control decision-making.展开更多
Surface water plays an essential role in the ecohydrological cycle,especially in water-scarce regions.Changes in surface water restrict social,economic,and agricultural development.However,the patterns and underlying ...Surface water plays an essential role in the ecohydrological cycle,especially in water-scarce regions.Changes in surface water restrict social,economic,and agricultural development.However,the patterns and underlying causes of surface water changes over varying frequencies in global arid regions remain unclear.Thus,this study investigated the changes in surface water and the underlying causes using the trend analysis and Spearman correlation coefficient on the basis of multi-source remote sensing and climate datasets across global arid regions during 2000–2020.The surface water was divided into temporary surface water(TSW),seasonal surface water(SSW),and permanent surface water(PSW)by calculating the surface water inundation frequency.Considering that surface water may be influenced by precipitation in the upper basins,we analyzed the response of surface water area to climatic factors at the basin scale.The area of all surface water(ASW)increased dramatically in global arid regions from 2000 to 2020,increasing from 61.88×104 to 67.40×104 km^(2);however,this increase was accompanied by a decrease in surface water inundation frequency.TSW increased by 55.46%relative to its area in 2000,with a net change rate of 3284.00 km^(2)/a.Changes in surface water were predominantly observed in the Kyzylkum Desert in Central Asia,the Thar Desert in southwestern Asia,and the deserts in Oceania.Precipitation had a significant effect on SSW and TSW at the basin scale.The correlation between precipitation and SSW area can reach 0.808 in the Indus River Basin of the Thar Desert(P<0.01).The findings provide a more comprehensive understanding of surface water variability in global arid regions,carrying significant practical implications for the scientific management of surface water at different frequencies.展开更多
Conversation A(in the coffee shop)Zach:What are you doing,Emily?I'm planning an event.I'm calling it“Neighborhood Snow Party!”Emily:Zach:Fun!When is it?It's this Saturday,January 31st.What's the time...Conversation A(in the coffee shop)Zach:What are you doing,Emily?I'm planning an event.I'm calling it“Neighborhood Snow Party!”Emily:Zach:Fun!When is it?It's this Saturday,January 31st.What's the time and place?It's from 10 a.m.to 4 p.m.at Emily:Zach:Emily:Green Hill Park.Zach:I can go!展开更多
This study proposes a framework for the concept of“new quality productive forces”in the ice and snow economy(ISE)as a strategic response to global climate change and the demands of technological and industrial trans...This study proposes a framework for the concept of“new quality productive forces”in the ice and snow economy(ISE)as a strategic response to global climate change and the demands of technological and industrial transformation for high-quality development.These new quality productive forces in the ISE have developed alongside the zonal distribution of natural resources,strictly adhere to ecological principles,and integrate value transformation mechanisms specific to ice and snow resources.Their development is projected to generate multiple benefits across ecological,economic,and social dimensions.The new quality productive forces in the ISE are characterized by technology-driven resource development,synergistic integration across the entire ice and snow industry value chain,and a focus on high-quality,green growth.Grounded in geography and economics,the new quality productive forces in the ISE link scientific innovation,the reallocation of productive factors,and industrial upgrading within the context of resource constraints.Furthermore,they expand the growth potential of the ISE by fostering new production relations through digital,intelligent,and green integration,while advancing low-carbon,sustainable development under the guiding principle that“ice and snow landscapes are also mountains of gold and silver.”For China's ISE,these new quality productive forces emphasize rigorous resource protection,balanced human-environment relationships,a resilient integrated supply chain framework,and an efficient“dual circulation”economic model.Practical strategies include integrating production factors,optimizing spatial resource allocation,fostering industrial synergy,and adapting production relations,all aimed at advancing the sustainable and high-quality development of China's ISE.展开更多
The snow density is a fundamental variable of the snow physical evolution processes,which can reflect the snowpack condition due to the thermal and gravitational compaction.Snow density is a bridge to transfer snow de...The snow density is a fundamental variable of the snow physical evolution processes,which can reflect the snowpack condition due to the thermal and gravitational compaction.Snow density is a bridge to transfer snow depth to snow water equivalent(SWE)for the snow water resources research.Therefore,it is important to understand the spatiotemporal distribution of snow density for the appropriate estimation of SWE.In this study,in situ snow densities from more than 6,000 stations in the Northern Hemisphere were used to analyze the spatial and temporal variations in snow density.The results displayed that snow density varied spatially and temporally in the Northern Hemisphere,with range of below 0.1 to over 0.4 g/cm^(3).The average snow densities in the mountainous regions of western North America,southeastern Canada,and Europe range from approximately 0.24 to 0.26 g/cm^(3),which is significantly greater than the values of 0.16–0.17 g/cm^(3)observed in Siberia,central Canada,the Great Plains of the United States,and China.The seasonal growth rates also present large spatial heterogeneity.The rates are over 0.024 g/cm^(3)per month in Southeastern Canada,the west mountain of North America and Europe,approximately 0.017 g/cm^(3)per month in Siberia,much larger than approximately 0.004 g/cm^(3)per month in other regions.Snow cover duration is a critical factor to determine the snow density.This study endorses the small snow density in China based on meteorological station observations,which results from that the meteorological stations are dominantly distributed in plain areas with relative short snow cover duration and shallow snow.展开更多
基金National Key R&D Program of China,No.2017YFA0603300Strategic Priority Research Program of the Chinese Academy of Sciences,No.XDA19040101。
文摘We collected and verified documentary records of the latest spring snowing dates(LSSD)in Hangzhou during Southern Song Dynasty.Furtherly,the statistical correlation between this proxy and February–April mean temperature in Hangzhou was examined,and samples later than the perennial mean of the LSSD during Southern Song Dynasty were transformed into the decadal mean of LSSD by means of Boltzmann function.General characteristics of this reconstructed LSSD series with a 10-year temporal resolution was analyzed,and it was also compared with other documentary evidences and reconstructed climate series in China for the period 1131–1270.The results and discussion suggested that:(1)Records of the LSSD in Hangzhou during Southern Song Dynasty did not refer to ice pellets and graupels,which had an explicit climate significance(–0.34℃/10 d,R2=0.37,p<0.001).However,when this proxy is used to reconstruct temperature changes,all dates should be converted into proleptic Gregorian style and meet the same criterion of"true Qi"as the Chinese traditional calendar after 1929.(2)The decadal mean of LSSD can be effectively estimated by using the forefront of LSSD in the decade on the basis of Boltzmann function,whose extrapolation has a lesser uncertainty than those on the basis of linear models or polynomial models.(3)The spring climate in Hangzhou during 1131–1270 was almost as warm as the period 1951–1980.At the centennial scale,this period can be divided into two phases:the cold 1131–1170 and the warm 1171–1270.In the latter,1181–1200 and 1221–1240 were two cold intervals at the multi-decadal scale.(4)The reconstructed LSSD series was consistent well with other documentary evidences and reconstructed climate series in China for 1131–1270,which may reflect the influence on the climate over most regions of China imposed by the Pacific Decadal Oscillation(PDO).
文摘SINCE December 2025,Urumqi City and Altay Prefecture in northwest China’s Xinjiang Uygur Autonomous Region,and northeast China’s Jilin Province have both entered their snow seasons.The snow holidays(for primary and secondary school students)in Urumqi and Altay ran from December 1 to 5.When combined with the preceding and following weekends,the holiday extended to nine days.
文摘Yiwu merchants ride a winter sports boom as“Made in China”winter gear heats up the global economy.YIWU,located in east China’s Zhejiang Province,is globally renowned as a hub for small commodities.This winter,its snow and ice sports products are generating a surge in business.Products such as snowboards,ski goggles,and ski poles are drawing an increasing number of merchants worldwide for purchases.
基金supported by the National Key Research and Development Project of China(2025YFE0103300)the National Natural Science Foundation of China(W2412135)+2 种基金the Natural Science Foundation of Xinjiang Uygur Autonomous Region(2024D01A143,2025D01B165)the China Postdoctoral Science Foundation(GZC20250226)the S&T Innovation and Development Project of Information Institution of Ministry of Emergency Management,China(2024506).
文摘Tajikistan,a mountainous country and a vital water tower for Central Asia,is becoming increasingly vulnerable to snow drought under climate change,threatening its snow-and glacier-fed streamflow.Yet,the impacts of snow drought on the regional hydrology remain insufficiently understood.In this study,we integrated multisource data,including the Fifth Generation European Centre for Medium-Range Weather Forecasts Atmospheric Reanalysis for Land Applications(ERA5-Land)data and hydrological station data,to systematically assess the snow drought patterns and their impacts on streamflow during 1950–2023.We identified snow drought events based on precipitation and snow fraction anomalies relative to climatological means and classified them into warm snow drought,dry snow drought,and warm&dry snow drought.The results revealed that snow drought was a recurrent phenomenon,occurring in 51.70%of the years during the study period,with warm&dry snow drought accounting for 21.90%of the total events.Both the frequency and severity exhibited pronounced spatial variability,largely governed by the elevation and snowfall fraction.Specifically,the frequency of warm snow drought was negatively correlated with the snowfall fraction,decreasing on average by 0.20 per unit increase in snowfall fraction,whereas the frequency of dry snow drought was positively correlated,increasing by 0.07 per unit increase.The streamflow analysis results demonstrated that snow drought typically reduced the warm-season discharge by 5.00%–18.00%in certain rivers,thereby exacerbating the water stress during the dry season.The results of this study advance our understanding by explicitly linking the types of snow drought to hydrological responses in Central Asia’s high mountains,providing a scientific basis for climate adaptation and sustainable water resource management in Tajikistan.
文摘China’s winter sports boom creates jobs and spurs economic growth,bringing substantial benefit to the general public,local governments,and businesses.CHINA’s ice and snow economy,riding on the winter sports boom,is stimulating consumption across the country,fueling regional development and creating new industrial ecosystems.This trend perfectly matches one of China’s key tasks for 2026.
文摘How is a nation’s embrace of snow and ice shaping a new cultural identity and igniting a multi-trillion-yuan economic boom?ADRIAAN Smit now cannot imagine a life without snowboarding,a passion that has become central to his world.He is excited to witness how winter sports are fostering a new winter culture in China.Listening to Smit speaking so enthusiastically about the slopes,one might assume he was raised in a region where snow sports are a way of life,but the fact is quite the contrary.
文摘Yiwu merchants ride a winter sports boom as“Made in China”gear heats up the global economy Yiwu,located in east China’s Zhejiang Province,is globally renowned as a hub for small commodities.This winter,its snow and ice sports products are generating a surge in business.
基金financial support from the Shanghai Science and Technology Committee(Grant no.24DZ3100504)the National Key Research and Development Program of China(Grant no.2022YFC2807102).
文摘Abstract To investigate the use of the three-point bending method and supplement the corresponding strength data of compacted snow for transportation-related applications in cold regions,compacted snow beams with an average density of 592 kg·m−3 were fabricated and tested at three distinct flexural strain rates.Each strain rate corresponded to the ductile,transitional,and brittle behavior of compacted snow,respectively.The flexural strength,ranging from 0.518 to 0.933 MPa,peaks at the ductile-to-brittle transition,while the flexural modulus,varying between 48.97 and 287.72 MPa,increases with strain rate within the tested range.At the same strain rate corresponding to brittle failure,both mechanical properties of compacted snow exhibit higher values than those of natural snow tested by the authors.Notably,the flexural strain rate at the ductile-to-brittle transition for compacted snow identified in this study is comparable to those previously reported for natural snow under uniaxial tension.Additionally,the obtained strength data are thoroughly compared with existing literature,with detailed discussions provided.The loading rates associated with typical failure modes of compacted snow under bending,together with the obtained strength values,provide methodological guidance and reference data for future in situ testing of compacted snow structures.
文摘As the wheel of time turns toward the year's end and the beginning of the new year,the snow-kissed land of Xizang gracefully unveils its grandeur and offers a feast of wonders for all to explore.Here,crystalline ice and snow form a celestial winter realm.Amid the biting seasonal winds,o month-long New Year celebration brings one o deep,heartfelt warmth.Rarely witnessed elsewhere in the world,this collection of New Year customs stands as both a cultural marvel and a warm gift that the plateau bestows upon the depths of winter.
文摘PHOTO NEWS Unforgettable Winter Break Tourists take selfies in front of snow sculptures in the Fenghuang Mountain Scenic Area,Yakeshi City in Inner Mongolia Autonomous Region,on December 7,2025.
文摘China’s winter sports boom is expanding beyond its traditional northern heartlands,fueling a dynamic ice-snow economy and culture nationwide.This seasonal surge is driven by sustained investment and innovative development models that are turning cold climates into hot economic opportunities.
基金supported by the National Natural Science Foundation of China(U2003202,42071054)the Key Research and Development Program of Jiangxi Province,China(20223BBG74003)the Science and Technology Planning Project of Nanjing Institute of Geography and Limnology(NIGLAS2022GS09).
文摘The Balkhash Lake Basin(BLB),a vital Central Asian watershed,faces hydrological uncertainty under climate warming.This study integrated multi-source remote sensing data(Sentinel-1 snow depth,Randolph Glacier Inventory(RGI)v.7.0 glacier inventory,and Advanced Spaceborne Thermal Emission and Reflection Radiometer(ASTER)mass balance)with a degree-day model to reconstruct decadal snow and ice dynamics across 13 sub-basins and analyzed their hydrological impacts from 1950 to 2014.The results showed that:(1)while flows from the downstream river of the BLB decreased from 1950 to 1982 due to land surface changes,runoff increased significantly after 1982 in the Ili River(18.0%)and moderately increased in most rivers in the east(1.3%–8.3%),driven by increased precipitation and glacier melt.Runoff in the Ayaguz catchment(no glaciers with the highest climate warming)declined(10.5%);(2)climate warming reduced precipitation falling as snow caused snow melt water to decline(0.03–0.22 mm/a)across the BLB,leading to downward shifts in runoff and runoff coefficient,especially in the rivers in the east.However,snow melt during April–June positively correlated with runoff coefficient,contributing to an upward shift in the Ili River Basin;and(3)meltwater from glacierized areas(<5.0%of basin area)contributed to 14.3%of total ablation water.Net glacier melt provided substantial excess flows(11.6 m3/s in the Ili River and<1.0 m3/s in the rivers in the east),generally counterbalancing the negative effect of rising potential evaporation at decadal scales and positively correlating with the runoff coefficient.Therefore,water stress in the BLB may be more severe in the future due to the accelerating glacier melt after the abrupt increase in air temperature in 2000,the continuing decline in snow melt,and the significant inter-annual variations in precipitation.
基金supported by the State Grid Shanxi Electric Power Company science and technology project“Research on Key Technologies for Voltage Stability Analysis and Control of UHV Transmission Sending-End Grid with Large-Scale Integration of Wind-Solar-Storage Systems”(520530240026).
文摘To address the issue of transient low-voltage instability in AC-DC hybrid power systems following large disturbances,conventional voltage assessment and control strategies typically adopt a sequential“assess-then-act”paradigm,which struggles to simultaneously meet the requirements for both high accuracy and rapid response.This paper proposes a transient voltage assessment and control method based on a hybrid neural network incorporated with an improved snow ablation optimization(ISAO)algorithm.The core innovation of the proposed method lies in constructing an intelligent“physics-informed and neural network-integrated”framework,which achieves the integration of stability assessment and control strategy generation.Firstly,to construct a highly correlated input set,response characteristics reflecting the system’s voltage stable/unstable states are screened.Simultaneously,the transient voltage severity index(TVSI)is introduced as a comprehensive metric to quantify the system’s post-disturbance transient voltage performance.Furthermore,the load bus voltage sensitivity index(LVSI)is defined as the ratio of the voltage change magnitude at a load node(or bus)to the change in the system-level TVSI,thereby pinpointing the response characteristics of critical load nodes.Secondly,both the transient voltage stability assessment result and its corresponding under-voltage load shedding(UVLS)control amount are jointly utilized as the outputs of the response-driven model.Subsequently,the snow ablation optimization(SAO)algorithm is enhanced using a good point set strategy and a Gaussian mutation strategy.This improved algorithm is then employed to optimize the key hyperparameters of the hybrid neural network.Finally,the superiority of the proposed method is validated on a modified CEPRI-36 system and an actual power grid case.Comparisons with various artificial intelligence methods demonstrate its significant advantages in model speed and accuracy.Additionally,when compared to traditional emergency control schemes and UVLS strategies,the proposed method exhibits exceptional rapidness and real-time capability in control decision-making.
基金supported by the National Key Research and Development Program of China(2023YFC3208701)the Fundamental Research Funds for the Central Universities(B210201035).
文摘Surface water plays an essential role in the ecohydrological cycle,especially in water-scarce regions.Changes in surface water restrict social,economic,and agricultural development.However,the patterns and underlying causes of surface water changes over varying frequencies in global arid regions remain unclear.Thus,this study investigated the changes in surface water and the underlying causes using the trend analysis and Spearman correlation coefficient on the basis of multi-source remote sensing and climate datasets across global arid regions during 2000–2020.The surface water was divided into temporary surface water(TSW),seasonal surface water(SSW),and permanent surface water(PSW)by calculating the surface water inundation frequency.Considering that surface water may be influenced by precipitation in the upper basins,we analyzed the response of surface water area to climatic factors at the basin scale.The area of all surface water(ASW)increased dramatically in global arid regions from 2000 to 2020,increasing from 61.88×104 to 67.40×104 km^(2);however,this increase was accompanied by a decrease in surface water inundation frequency.TSW increased by 55.46%relative to its area in 2000,with a net change rate of 3284.00 km^(2)/a.Changes in surface water were predominantly observed in the Kyzylkum Desert in Central Asia,the Thar Desert in southwestern Asia,and the deserts in Oceania.Precipitation had a significant effect on SSW and TSW at the basin scale.The correlation between precipitation and SSW area can reach 0.808 in the Indus River Basin of the Thar Desert(P<0.01).The findings provide a more comprehensive understanding of surface water variability in global arid regions,carrying significant practical implications for the scientific management of surface water at different frequencies.
文摘Conversation A(in the coffee shop)Zach:What are you doing,Emily?I'm planning an event.I'm calling it“Neighborhood Snow Party!”Emily:Zach:Fun!When is it?It's this Saturday,January 31st.What's the time and place?It's from 10 a.m.to 4 p.m.at Emily:Zach:Emily:Green Hill Park.Zach:I can go!
基金The Third Scientific Expedition Project in Xinjiang,No.2022xjkk0905Project Commissioned by the General Administration of Sport of ChinaProject Commissioned by the Ministry of Culture and Tourism of the People’s Republic of China。
文摘This study proposes a framework for the concept of“new quality productive forces”in the ice and snow economy(ISE)as a strategic response to global climate change and the demands of technological and industrial transformation for high-quality development.These new quality productive forces in the ISE have developed alongside the zonal distribution of natural resources,strictly adhere to ecological principles,and integrate value transformation mechanisms specific to ice and snow resources.Their development is projected to generate multiple benefits across ecological,economic,and social dimensions.The new quality productive forces in the ISE are characterized by technology-driven resource development,synergistic integration across the entire ice and snow industry value chain,and a focus on high-quality,green growth.Grounded in geography and economics,the new quality productive forces in the ISE link scientific innovation,the reallocation of productive factors,and industrial upgrading within the context of resource constraints.Furthermore,they expand the growth potential of the ISE by fostering new production relations through digital,intelligent,and green integration,while advancing low-carbon,sustainable development under the guiding principle that“ice and snow landscapes are also mountains of gold and silver.”For China's ISE,these new quality productive forces emphasize rigorous resource protection,balanced human-environment relationships,a resilient integrated supply chain framework,and an efficient“dual circulation”economic model.Practical strategies include integrating production factors,optimizing spatial resource allocation,fostering industrial synergy,and adapting production relations,all aimed at advancing the sustainable and high-quality development of China's ISE.
基金funded by the National Natural Science Foundation of China(Grant Nos:42125604&42171143)the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(Grant No.2019QZKK0201)。
文摘The snow density is a fundamental variable of the snow physical evolution processes,which can reflect the snowpack condition due to the thermal and gravitational compaction.Snow density is a bridge to transfer snow depth to snow water equivalent(SWE)for the snow water resources research.Therefore,it is important to understand the spatiotemporal distribution of snow density for the appropriate estimation of SWE.In this study,in situ snow densities from more than 6,000 stations in the Northern Hemisphere were used to analyze the spatial and temporal variations in snow density.The results displayed that snow density varied spatially and temporally in the Northern Hemisphere,with range of below 0.1 to over 0.4 g/cm^(3).The average snow densities in the mountainous regions of western North America,southeastern Canada,and Europe range from approximately 0.24 to 0.26 g/cm^(3),which is significantly greater than the values of 0.16–0.17 g/cm^(3)observed in Siberia,central Canada,the Great Plains of the United States,and China.The seasonal growth rates also present large spatial heterogeneity.The rates are over 0.024 g/cm^(3)per month in Southeastern Canada,the west mountain of North America and Europe,approximately 0.017 g/cm^(3)per month in Siberia,much larger than approximately 0.004 g/cm^(3)per month in other regions.Snow cover duration is a critical factor to determine the snow density.This study endorses the small snow density in China based on meteorological station observations,which results from that the meteorological stations are dominantly distributed in plain areas with relative short snow cover duration and shallow snow.
