Arctic sea ice is an essential component of the climate system and plays an important role in global climate change.This study calculates the volume flux through Fram Strait(FS)and the sea ice volume in the Greenland ...Arctic sea ice is an essential component of the climate system and plays an important role in global climate change.This study calculates the volume flux through Fram Strait(FS)and the sea ice volume in the Greenland Sea(GS)from 1979 to 2022,and analyzes trends before and after 2000.In addition,the contributions of advection and local processes to sea ice volume variations in the GS during different seasons are compared.The influence of the surface air temperature(SAT)and the sea surface temperature(SST)on sea ice volume variations is discussed,as well as the impact of atmospheric circulation on sea ice.Results indicate no significant trend in the sea ice volume flux through FS from 1979 to 2022.However,the sea ice volume in the GS exhibited a notable decreasing trend.Compared with the period of 1979-2000,the sea ice volume decreasing trend accelerated significantly during the period of 2001-2022.During winter,ice advection from the central Arctic Ocean exert a strong influence on the sea ice volume variations in the GS,whereas during summer,local processes,including the interactions with the atmosphere and ocean,as well as the dynamic process of sea ice itself,exert a considerable impact.The sea ice volume in the GS declined rapidly after 2000.Furthermore,the effects of local processes on sea ice have intensified,with the SST exerting a stronger influence on the sea ice volume variations in the GS than the SAT.The positive Arctic oscillation and dipole anomaly are important drivers for the transport of Arctic sea ice to the GS.The Winter North Atlantic oscillation intensifies ocean heat content,affecting sea ice in the GS.展开更多
The ground ice content in permafrost serves as one of the dominant properties of permafrost for the study of global climate change, ecology, hydrology and engineering construction in cold regions. This paper initially...The ground ice content in permafrost serves as one of the dominant properties of permafrost for the study of global climate change, ecology, hydrology and engineering construction in cold regions. This paper initially attempts to assess the ground ice volume in permafrost layers on the Qinghai-Tibet Plateau by considering landform types, the corresponding lithological composition, and the measured water content in various regions. An approximation demonstrating the existence of many similarities in lithological composition and water content within a unified landform was established during the calculations. Considerable knowledge of the case study area, here called the Source Area of the Yellow(Huanghe) River(SAYR) in the northeastern Qinghai-Tibet Plateau, has been accumulated related to permafrost and fresh water resources during the past 40 years. Considering the permafrost distribution, extent, spatial distribution of landform types, the ground ice volume at the depths of 3.0–10.0 m below the ground surface was estimated based on the data of 101 boreholes from field observations and geological surveys in different types of landforms in the permafrost region of the SAYR. The total ground ice volume in permafrost layers at the depths of 3.0–10.0 m was approximately(51.68 ± 18.81) km^3, and the ground ice volume per unit volume was(0.31 ± 0.11) m^3/m^3. In the horizontal direction, the ground ice content was higher in the landforms of lacustrine-marshland plains and alluvial-lacustrine plains, and the lower ground ice content was distributed in the erosional platforms and alluvial-proluvial plains. In the vertical direction, the volume of ground ice was relatively high in the top layers(especially near the permafrost table) and at the depths of 7.0–8.0 m. This calculation method will be used in the other areas when the necessary information is available, including landform type, borehole data, and measured water content.展开更多
The Fram Strait（FS） is the primary region of sea ice export from the Arctic Ocean and thus plays an important role in regulating the amount of sea ice and fresh water entering the North Atlantic seas. A 5 a（2011–2...The Fram Strait（FS） is the primary region of sea ice export from the Arctic Ocean and thus plays an important role in regulating the amount of sea ice and fresh water entering the North Atlantic seas. A 5 a（2011–2015） sea ice thickness record retrieved from Cryo Sat-2 observations is used to derive a sea ice volume flux via the FS. Over this period, a mean winter accumulative volume flux（WAVF） based on sea ice drift data derived from passivemicrowave measurements, which are provided by the National Snow and Ice Data Center（NSIDC） and the Institut Francais de Recherche pour d＇Exploitation de la Mer（IFREMER）, amounts to 1 029 km^3（NSIDC） and1 463 km^3（IFREMER）, respectively. For this period, a mean monthly volume flux（area flux） difference between the estimates derived from the NSIDC and IFREMER drift data is –62 km^3 per month（–18×10~6 km^2 per month）.Analysis reveals that this negative bias is mainly attributable to faster IFREMER drift speeds in comparison with slower NSIDC drift data. NSIDC-based sea ice volume flux estimates are compared with the results from the University of Bremen（UB）, and the two products agree relatively well with a mean monthly bias of（5.7±45.9） km^3 per month for the period from January 2011 to August 2013. IFREMER-based volume flux is also in good agreement with previous results of the 1990 s. Compared with P1（1990/1991–1993/1994） and P2（2003/2004–2007/2008）, the WAVF estimates indicate a decline of more than 600 km^3 in P3（2011/2012–2014/2015）. Over the three periods, the variability and the decline in the sea ice volume flux are mainly attributable to sea ice motion changes, and second to sea ice thickness changes, and the least to sea ice concentration variations.展开更多
By combing satellite-derived ice motion and concentration with ice thickness fields from a popular model PIOMAS we obtain the estimates of ice volume flux passing the Fram Strait over the 1979–2012 period. Since curr...By combing satellite-derived ice motion and concentration with ice thickness fields from a popular model PIOMAS we obtain the estimates of ice volume flux passing the Fram Strait over the 1979–2012 period. Since current satellite and field observations for sea ice thickness are limited in time and space, the use of PIOMAS is expected to fill the gap by providing temporally continued ice thickness fields. Calculated monthly volume flux exhibits a prominent annual cycle with the peak record in March（roughly 145 km3/month） and the trough in August（10 km^3/month）. Annual ice volume flux（1 132 km^3） is primarily attributable to winter（October through May） outflow（approximately 92%）. Uncertainty in annual ice volume export is estimated to be 55 km^3（or 5.7%）. Our results also verified the extremely large volume flux appearing between late 1980 s and mid-1990 s. Nevertheless, no clear trend was found in our volume flux results. Ice motion is the primary factor in the determination of behavior of volume flux. Ice thickness presented a general decline trend may partly enhance or weaken the volume flux trend. Ice concentration exerted the least influences on modulating trends and variability in volume flux. Moreover, the linkage between winter ice volume flux and three established Arctic atmospheric schemes were examined. Compared to NAO, the DA and EOF3 mechanism explains a larger part of variations of ice volume flux across the strait.展开更多
Arctic sea ice export is important for the redistribution of freshwater and sea ice mass.Here,we use the sea ice thickness,sea ice velocity,and sea ice concentration(SIC)to estimate the exported sea ice volume through...Arctic sea ice export is important for the redistribution of freshwater and sea ice mass.Here,we use the sea ice thickness,sea ice velocity,and sea ice concentration(SIC)to estimate the exported sea ice volume through the Fram Strait from 2011 to 2018.We further analyse the contributions of the sea ice thickness,velocity and concentration to sea ice volume export.Then,the relationships between atmospheric circulation indices(Arctic Oscillation(AO),North Atlantic Oscillation(NAO),and Arctic Dipole(AD))and the sea ice volume export are discussed.Finally,we analyse the impact of wind-driven oceanic circulation indices(Ekman transport(ET))on the sea ice volume export.The sea ice volume export rapidly increases in winter and decreases in spring.The exported sea ice volume in winter is likely to exceed that in spring in the future.Among sea ice thickness,velocity and SIC,the greatest contribution to sea ice export comes from the ice velocity.The exported sea ice volume through the zonal gate of the Fram Strait(which contributes 97%to the total sea ice volume export of the Fram Strait)is much higher than that through the meridional gate(3%)because the sea ice flowing out of the zonal gate has the characteristics of a high thickness(mainly thicker than 1 m),a high velocity(mainly faster than 0.06 m/s)and a high concentration(mainly higher than 80%).The AD and ET explain 53.86%and 38.37%of the variation in sea ice volume export,respectively.展开更多
ICE(inducer of CBF expression)基因家族是植物低温信号转导通路中的重要转录调控因子之一,为系统解析白菜型油菜中ICE家族的成员特征及其低温响应表达模式,基于白菜型油菜全基因组数据,通过BLAST与HMM方法鉴定出74个ICE基因家族成员...ICE(inducer of CBF expression)基因家族是植物低温信号转导通路中的重要转录调控因子之一,为系统解析白菜型油菜中ICE家族的成员特征及其低温响应表达模式,基于白菜型油菜全基因组数据,通过BLAST与HMM方法鉴定出74个ICE基因家族成员。染色体定位结果显示,该家族在全部10条染色体上均有分布,其中以第9号染色体上成员数最多。蛋白质特性分析显示,所有成员均定位于细胞核,分子量和等电点差异较大,70个成员蛋白不稳定性指数超过稳定性阈值。基因结构与保守功能模块分析揭示成员间结构组成存在多样性,其中Motif 1和Motif 2在绝大多数成员中高度保守。共线性分析表明,该家族扩展主要受全基因组复制与片段复制事件驱动。启动子区顺式调控元件分析显示大部分基因含有光响应、ABA、MeJA及MYB结合位点等顺式调控元件,其中34个BraICE含有低温响应元件。基于西藏白菜型油菜转录组数据的表达分析发现,BraICE17在低温处理后表达上调幅度最大,BraICE35表达下调幅度最为明显,qRT-PCR实验总体支持转录组数据的可靠性。本研究结果为进一步解析BraICE的分子功能与低温应答机制奠定了理论基础,并提供了潜在的耐寒研究基因资源。展开更多
Prydz Bay,East Antarctica,is a critical region for studying ocean–sea ice–ice shelf interactions and their role in the global climate system.This review synthesizes the advancements in numerical modeling of physical...Prydz Bay,East Antarctica,is a critical region for studying ocean–sea ice–ice shelf interactions and their role in the global climate system.This review synthesizes the advancements in numerical modeling of physical oceanographic processes in Prydz Bay,highlighting the evolution from early one-dimensional thermodynamic models to contemporary high-resolution,three-dimensional coupled ocean–sea ice–ice shelf frameworks.We discuss key milestones in understanding processes such as frazil ice dynamics and its impact on the basal mass balance of the Amery Ice Shelf,the pathways and mechanisms of Modified Circumpolar Deep Water intrusions,and the dynamic influences of large icebergs on regional circulation.Despite significant progress,challenges remain in integrating multi-component interactions and achieving long-term,high-resolution climate projections.Future efforts should focus on developing fully coupled models that incorporate atmosphere–ocean–sea ice–ice shelf–iceberg interactions,supported by enhanced observational networks and improved computational efficiency.This review underscores the importance of continued modeling advancement to better predict the responses of Antarctic ice shelves and polar climate to global change.展开更多
Predicting Antarctic sea ice is of substantial academic and practical significance.However,current prediction models,including deep learning(DL)-based models,show notable bias in the marginal ice zone.In this study,we...Predicting Antarctic sea ice is of substantial academic and practical significance.However,current prediction models,including deep learning(DL)-based models,show notable bias in the marginal ice zone.In this study,we developed a pure data-driven DL model for predicting the Antarctic austral summer monthly-to-seasonal sea ice concentration(SIC)by incorporating a novel hybrid sea ice edge constraint loss function(HybridLoss).The model is referred to as ASICNet.Independent testing based on the last five years(2019–23)demonstrates that ASICNet with HybridLoss achieves significantly higher skill metrics than without,with a reduced mean absolute error of 0.021 from 0.022,a reduced integrated ice edge error of 1.714×10^(6)from 1.794×10^(6)km^(2),but an increased pattern correlation coefficient of 0.40 from 0.38,although both ASICNet versions outperform dynamical and statistical models.Furthermore,enhanced heat maps were developed to interpret the predictability sources of sea ice within DL-based models,and the results suggest that the predictability of Antarctic sea ice is attributable to factors like the Antarctic Dipole(ADP),Amundsen Sea Low(ASL),and Southern Ocean sea surface temperature(SST),as revealed in previous studies.Thus,ASICNet is an efficient tool for austral summer Antarctic SIC prediction.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
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
Rock-ice avalanches in cold high-mountain regions pose severe hazards due to their high mobility,yet the quantitative controls of particle-size ratio and ice content remain insufficiently constrained.This study invest...Rock-ice avalanches in cold high-mountain regions pose severe hazards due to their high mobility,yet the quantitative controls of particle-size ratio and ice content remain insufficiently constrained.This study investigates their coupled effects using inclinedflume experiments and Discrete Element Method(DEM)simulations,covering three gravel sizes(2-5 mm,5-7 mm,7-10 mm)and four ice-content levels(0%,20%,40%,60%).Run-out distance,velocity,energy components,flow regime(Savage number),and segregation indexαwere quantified.Increasing ice content significantly enhances mobility,but with diminishing marginal effectiveness.From 0%to 40%ice content,run-out distance increases by 41%-86%,whereas the additional increase from 40%to 60%contributes only 12%-23%.Particle-size ratio strongly governs segregation intensity.Fine-gravel groups reach segregation indices ofα=0.92-0.98,indicating nearly complete upward migration of ice,whereas medium-gravel and coarse-gravel groups exhibit much weaker segregation,stabilizing atα=0.68-0.74 and 0.60-0.69.Savage number analyses reveal marked flow-regime transitions.At 0%ice content,Savage numbers reach 1.0-1.5,indicating a collisional regime.Increasing ice content suppresses collisionality,with Savage numbers decreasing to 0.03-0.07 at 60%ice content,consistent with dense-regime flow.DEM energy analyses confirm this regime shift:for finegravel mixtures,collision energy decreases by 14%,while sliding-friction energy increases by 33%as ice content increases from 0%to 60%,reflecting enhanced overburden effects imposed by upward-segregated ice layers.Medium and coarse mixtures exhibit weaker or opposite energy-shift patterns,demonstrating strong size dependence.Mechanistically,large particle-size contrasts promote strong segregation and form dense basal rock layers that increase basal friction and reduce mobility.When particle sizes are similar or ice content is high,segregation remains limited,allowing ice to mix into the basal layer,thereby reducing basal friction and enhancing mobility.This research quantitatively demonstrates how composition controls particle spatial distribution,flow regime,and energy dissipation,offering new mechanistic insights into the propagation and deposition behaviors of rock-ice avalanches and improving hazard assessment in vulnerable high-mountain regions.展开更多
The correlation between the Soil Moisture and Ocean Salinity(SMOS)L-band brightness temperature and thin sea ice thickness has been widely exploited using semi-empirical retrieval approaches based on a single-tie poin...The correlation between the Soil Moisture and Ocean Salinity(SMOS)L-band brightness temperature and thin sea ice thickness has been widely exploited using semi-empirical retrieval approaches based on a single-tie point(STP).However,due to pronounced spatial heterogeneity in seawater and sea ice properties across the Arctic,the use of an STP often leads to regionally biased.To address this limitation,this study proposes a multi-tie point(MTP)sea ice thickness retrieval method based on SMOS brightness temperature and sea ice concentration time series.Multiple seawater and sea ice tie-point values are identified through point-by-point time series analysis,quality control,and statistical hypothesis testing,allowing spatial variability in radiometric properties to be explicitly considered.The MTP-based retrieval is applied to Arctic freeze-up conditions.Validation against independent SMOS thin sea ice thickness products shows that the MTP approach yields significantly reduced bias and root mean square error compared with the conventional STP method,with statistically significant improvements confirmed by paired t-tests.While retrieval accuracy stabilizes beyond a certain number of tie points,the preprocessing cost associated with tie-point selection increases substantially.Considering both accuracy and efficiency,the MTP framework provides a practical and robust approach for large-scale Arctic thin sea ice thickness retrieval and enables improved characterization of regional freezing processes and maximum ice thickness.展开更多
Arctic sea ice concentration(SIC)prediction on a subseasonal scale plays an important role in polar navigation.To reduce the high uncertainty of daily forecasts,three time series prediction models are combined with em...Arctic sea ice concentration(SIC)prediction on a subseasonal scale plays an important role in polar navigation.To reduce the high uncertainty of daily forecasts,three time series prediction models are combined with empirical orthogonal function(EOF)decomposition to forecast Arctic pentad-mean SIC,where each month is divided into six pentad-means–the first five each span five days,and the last encompasses the remaining days,which may vary in length.The models were trained on SIC data from 1989 to2018 and tested from 2019 to 2023,with lead times ranging from 1 to 12 pentad-means.Model skill was evaluated based on SIC spatial patterns,sea ice area(SIA),and the sea ice edge in September from 2019 to 2023.The moving-averaged 2-m temperature helps reduce the long short-term memory model's error in the Beaufort and Chukchi Seas.Based on the models'scores for each EOF time series,weighted ensemble prediction results were obtained.These results outperform two benchmark models across all lead times.In addition,the ensemble prediction better reproduces the seasonal cycle of the SIA,with relative errors ranging from 1.04%to 3.85%.The predicted September ice edge closely matches observations,with binary accuracy consistently above 90%.Forecast models show the lowest errors in the central Arctic,while relatively higher errors appear in the Barents and Kara Seas.展开更多
Ice premelting,the formation of a quasi-liquid layer on ice surfaces below the bulk melting point,plays a crucial role in various processes,ranging from glacier dynamics to ice friction and surface chemistry.Despite i...Ice premelting,the formation of a quasi-liquid layer on ice surfaces below the bulk melting point,plays a crucial role in various processes,ranging from glacier dynamics to ice friction and surface chemistry.Despite intensive research,the microscopic structure of the premelting layer and underlying molecular mechanisms remain poorly understood.In this work,we studied the temperature-and pressure-dependent structural disordering of crystalline Ih(0001)surface near the onset of premelting on the atomic scale by qPlus-based cryogenic atomic force microscopy.The linear correlation between the density of planar local structure(PLS)and the fraction of disordered surface region showed that the PLS mediated early-stage premelting by serving as a metastable seeding state.Notably,the associated surface disordering is cooperative,extending over an area of roughly~2 nm^(2) around a PLS.We further found a striking structural similarity between the kinetic-trapped regime below the surface crystallization temperature(T_(c))and the premelting-dominated regime above T_(c).As the deposition pressure increased,the characteristic temperature dependence was preserved,with only T_(c) shifting to higher values due to kinetic effects.Finally,we proposed a surface phase diagram for ice Ih(0001)based on our experimental observations.展开更多
Ice crystal icing is an important cause of accidents in aircraft engines.Ice formation in aircraft engines can cause internal blades to freeze,affecting the quality of the air flow field and blocking the flow path.On ...Ice crystal icing is an important cause of accidents in aircraft engines.Ice formation in aircraft engines can cause internal blades to freeze,affecting the quality of the air flow field and blocking the flow path.On the other hand,the entry of ice crystal particles into the combustion chamber can cause a decrease in temperature or even flameout,leading to engine surge or shutdown.Therefore,it is necessary to conduct multiphase flow tests on ice crystals for aircraft components such as aircraft engines.Conducting ice crystal multiphase flow tests on aircraft is an effective research method,but it requires the construction of an ice crystal multiphase flow test platform that meets relevant technical requirements.The paper focuses on the relevant experimental requirements and combines wind tunnel test structures to conduct multiphase flow numerical simulations on various forms of jet pipelines,obtaining particle motion distribution results.After comparison,the optimal form of jet structure is obtained,providing the best selection scheme for the design of relevant wind tunnel structures.展开更多
Debate over the benefits and harms of icing acute muscle injuries remains unresolved.Some contend that ice is ineffective or even harmful,while others promote cryotherapy as a universal remedy.Centrists,often academic...Debate over the benefits and harms of icing acute muscle injuries remains unresolved.Some contend that ice is ineffective or even harmful,while others promote cryotherapy as a universal remedy.Centrists,often academics,call for more high-quality randomized controlled trials(RCTs)to resolve the issue.This viewpoint reframes the debate around 3 key points:first,although ice produces analgesia,evidence for sustained pain relief,beyond the immediate post-treatment period.展开更多
The rapid melting of Arctic sea ice poses significant risks to the safety of shipping routes.Accurate remote sensing data on sea ice concentration(SIC)is crucial for effective route planning of ships and ensuring navi...The rapid melting of Arctic sea ice poses significant risks to the safety of shipping routes.Accurate remote sensing data on sea ice concentration(SIC)is crucial for effective route planning of ships and ensuring navigational safety.Despite the availability of numerous SIC products in China,these datasets still lag behind mainstream international products in terms of data accuracy,spatiotemporal resolution,and time span.To enhance the accuracy of China's domestic SIC remote sensing data,this study used the SIC data derived from the passive microwave remote sensing dataset provided by the University of Bremen(BRM-SIC)as a reference to conduct a comprehensive evaluation and analysis of two additional SIC datasets:the dataset derived from the microwave radiation imager(MWRI)aboard the FY-3D satellite,provided by the National Satellite Meteorological Center(FY-SIC),and the dataset obtained through the DT-ASI algorithm from the microwave imager of the FY-3D satellite,provided by Ocean University of China(OUC-SIC).Based on the evaluation results,a TransUnet fusion correction model was developed.The performance of this model was then compared against Ordinary Least Squares(OLS),Random Forest(RF),and UNet correction models,through spatial and temporal analyses.Results indicate that,compared to FY-SIC data,the RMSE of the OUC-SIC data and the standard data is reduced by24.245%,while the R is increased by 12.516%.Overall,the accuracy of OUC-SIC data is superior to that of FY-SIC data.During the research period(2020–2022),the standard deviation(SD)and coefficient of variation(CV)of OUC-SIC were 3.877%and 10.582%,respectively,while those for FY-SIC were 7.836%and 7.982%,respectively.In the study area,compared with OUC-SIC data,FYSIC data exhibited a larger standard deviation of deviation and a smaller coefficient of variation of deviation across most sea areas.These results indicate that the OUC-SIC data exhibit better temporal and spatial stability,whereas the FY-SIC data show stronger relative dimensionless stability.Among the four correction models,all showed improvements over the original,unfused corrected data.The fusion corrections using the OLS,RF,UNet,and TransUnet models reduced RMSE by 5.563%,14.601%,42.927%,and48.316%,respectively.Correspondingly,R increased by 0.463%,1.176%,3.951%,and 4.342%,respectively.Among these models,TransUnet performed the best,effectively integrating the advantages of FY-SIC and OUC-SIC data and notably improving the overall accuracy and spatiotemporal stability of SIC data.展开更多
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
基金The National Key Research and Development Program of China under contract Nos 2021YFC2803303 and 2021YFC2803302the National Natural Science Foundation of China under contract No.42171133the Fundamental Research Funds for the Central Universities,China,under contract No.2042022dx0001.
文摘Arctic sea ice is an essential component of the climate system and plays an important role in global climate change.This study calculates the volume flux through Fram Strait(FS)and the sea ice volume in the Greenland Sea(GS)from 1979 to 2022,and analyzes trends before and after 2000.In addition,the contributions of advection and local processes to sea ice volume variations in the GS during different seasons are compared.The influence of the surface air temperature(SAT)and the sea surface temperature(SST)on sea ice volume variations is discussed,as well as the impact of atmospheric circulation on sea ice.Results indicate no significant trend in the sea ice volume flux through FS from 1979 to 2022.However,the sea ice volume in the GS exhibited a notable decreasing trend.Compared with the period of 1979-2000,the sea ice volume decreasing trend accelerated significantly during the period of 2001-2022.During winter,ice advection from the central Arctic Ocean exert a strong influence on the sea ice volume variations in the GS,whereas during summer,local processes,including the interactions with the atmosphere and ocean,as well as the dynamic process of sea ice itself,exert a considerable impact.The sea ice volume in the GS declined rapidly after 2000.Furthermore,the effects of local processes on sea ice have intensified,with the SST exerting a stronger influence on the sea ice volume variations in the GS than the SAT.The positive Arctic oscillation and dipole anomaly are important drivers for the transport of Arctic sea ice to the GS.The Winter North Atlantic oscillation intensifies ocean heat content,affecting sea ice in the GS.
基金Under the auspices of the Chinese Academy of Sciences(CAS)Key Research Program(No.KZZD-EW-13)National Natural Science Foundation of China(No.91647103)
文摘The ground ice content in permafrost serves as one of the dominant properties of permafrost for the study of global climate change, ecology, hydrology and engineering construction in cold regions. This paper initially attempts to assess the ground ice volume in permafrost layers on the Qinghai-Tibet Plateau by considering landform types, the corresponding lithological composition, and the measured water content in various regions. An approximation demonstrating the existence of many similarities in lithological composition and water content within a unified landform was established during the calculations. Considerable knowledge of the case study area, here called the Source Area of the Yellow(Huanghe) River(SAYR) in the northeastern Qinghai-Tibet Plateau, has been accumulated related to permafrost and fresh water resources during the past 40 years. Considering the permafrost distribution, extent, spatial distribution of landform types, the ground ice volume at the depths of 3.0–10.0 m below the ground surface was estimated based on the data of 101 boreholes from field observations and geological surveys in different types of landforms in the permafrost region of the SAYR. The total ground ice volume in permafrost layers at the depths of 3.0–10.0 m was approximately(51.68 ± 18.81) km^3, and the ground ice volume per unit volume was(0.31 ± 0.11) m^3/m^3. In the horizontal direction, the ground ice content was higher in the landforms of lacustrine-marshland plains and alluvial-lacustrine plains, and the lower ground ice content was distributed in the erosional platforms and alluvial-proluvial plains. In the vertical direction, the volume of ground ice was relatively high in the top layers(especially near the permafrost table) and at the depths of 7.0–8.0 m. This calculation method will be used in the other areas when the necessary information is available, including landform type, borehole data, and measured water content.
基金The National Natural Science Foundation of China under contract No.41406215the Foundation of Laboratory for Marine Geology,Institute of Oceanology,Chinese Academy of Sciences+3 种基金the Foundation of Qingdao National Laboratory for Marine Science and Technologythe Postdoctoral Science Foundation of China under contract No.2014M561971the Open Fund for the Key Laboratory of Marine Geology and Environment,Institute of Oceanology,Chinese Academy of Sciences under contract No.MGE2013KG07the NSFC-Shandong Joint Fund for Marine Science Research Centers under contract No.U1606401
文摘The Fram Strait（FS） is the primary region of sea ice export from the Arctic Ocean and thus plays an important role in regulating the amount of sea ice and fresh water entering the North Atlantic seas. A 5 a（2011–2015） sea ice thickness record retrieved from Cryo Sat-2 observations is used to derive a sea ice volume flux via the FS. Over this period, a mean winter accumulative volume flux（WAVF） based on sea ice drift data derived from passivemicrowave measurements, which are provided by the National Snow and Ice Data Center（NSIDC） and the Institut Francais de Recherche pour d＇Exploitation de la Mer（IFREMER）, amounts to 1 029 km^3（NSIDC） and1 463 km^3（IFREMER）, respectively. For this period, a mean monthly volume flux（area flux） difference between the estimates derived from the NSIDC and IFREMER drift data is –62 km^3 per month（–18×10~6 km^2 per month）.Analysis reveals that this negative bias is mainly attributable to faster IFREMER drift speeds in comparison with slower NSIDC drift data. NSIDC-based sea ice volume flux estimates are compared with the results from the University of Bremen（UB）, and the two products agree relatively well with a mean monthly bias of（5.7±45.9） km^3 per month for the period from January 2011 to August 2013. IFREMER-based volume flux is also in good agreement with previous results of the 1990 s. Compared with P1（1990/1991–1993/1994） and P2（2003/2004–2007/2008）, the WAVF estimates indicate a decline of more than 600 km^3 in P3（2011/2012–2014/2015）. Over the three periods, the variability and the decline in the sea ice volume flux are mainly attributable to sea ice motion changes, and second to sea ice thickness changes, and the least to sea ice concentration variations.
基金The National Natural Science Foundation of China under contract No.41406215the Foundation of Laboratory for Marine Geology,Qingdao National Laboratory for Marine Science and Technology,Postdoctoral Science Foundation of China under contract No.2014M561971the Open fund for the Key Laboratory of Marine Geology and Environment,Institute of Oceanology,Chinese Academy of Sciences under contract No.MGE2013KG07
文摘By combing satellite-derived ice motion and concentration with ice thickness fields from a popular model PIOMAS we obtain the estimates of ice volume flux passing the Fram Strait over the 1979–2012 period. Since current satellite and field observations for sea ice thickness are limited in time and space, the use of PIOMAS is expected to fill the gap by providing temporally continued ice thickness fields. Calculated monthly volume flux exhibits a prominent annual cycle with the peak record in March（roughly 145 km3/month） and the trough in August（10 km^3/month）. Annual ice volume flux（1 132 km^3） is primarily attributable to winter（October through May） outflow（approximately 92%）. Uncertainty in annual ice volume export is estimated to be 55 km^3（or 5.7%）. Our results also verified the extremely large volume flux appearing between late 1980 s and mid-1990 s. Nevertheless, no clear trend was found in our volume flux results. Ice motion is the primary factor in the determination of behavior of volume flux. Ice thickness presented a general decline trend may partly enhance or weaken the volume flux trend. Ice concentration exerted the least influences on modulating trends and variability in volume flux. Moreover, the linkage between winter ice volume flux and three established Arctic atmospheric schemes were examined. Compared to NAO, the DA and EOF3 mechanism explains a larger part of variations of ice volume flux across the strait.
基金The National Key Research and Development Program of China under contract No.2021YFC2803301the National Natural Science Foundation of China under contract Nos 41976212 and 41830105the Natural Science Foundation of Jiangsu Province under contract No.BK20210193.
文摘Arctic sea ice export is important for the redistribution of freshwater and sea ice mass.Here,we use the sea ice thickness,sea ice velocity,and sea ice concentration(SIC)to estimate the exported sea ice volume through the Fram Strait from 2011 to 2018.We further analyse the contributions of the sea ice thickness,velocity and concentration to sea ice volume export.Then,the relationships between atmospheric circulation indices(Arctic Oscillation(AO),North Atlantic Oscillation(NAO),and Arctic Dipole(AD))and the sea ice volume export are discussed.Finally,we analyse the impact of wind-driven oceanic circulation indices(Ekman transport(ET))on the sea ice volume export.The sea ice volume export rapidly increases in winter and decreases in spring.The exported sea ice volume in winter is likely to exceed that in spring in the future.Among sea ice thickness,velocity and SIC,the greatest contribution to sea ice export comes from the ice velocity.The exported sea ice volume through the zonal gate of the Fram Strait(which contributes 97%to the total sea ice volume export of the Fram Strait)is much higher than that through the meridional gate(3%)because the sea ice flowing out of the zonal gate has the characteristics of a high thickness(mainly thicker than 1 m),a high velocity(mainly faster than 0.06 m/s)and a high concentration(mainly higher than 80%).The AD and ET explain 53.86%and 38.37%of the variation in sea ice volume export,respectively.
基金supported by the Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(Grant nos.SML2021SP306,SML2023SP201)the National Key R&D Program of China(Grant no.2024YFF0506603)+1 种基金the National Natural Science Foundation of China(Grant no.42576020)Guangdong Basic and Applied Basic Research Foundation,China(Grant nos.2024A1515012717,2026A1515012241).
文摘Prydz Bay,East Antarctica,is a critical region for studying ocean–sea ice–ice shelf interactions and their role in the global climate system.This review synthesizes the advancements in numerical modeling of physical oceanographic processes in Prydz Bay,highlighting the evolution from early one-dimensional thermodynamic models to contemporary high-resolution,three-dimensional coupled ocean–sea ice–ice shelf frameworks.We discuss key milestones in understanding processes such as frazil ice dynamics and its impact on the basal mass balance of the Amery Ice Shelf,the pathways and mechanisms of Modified Circumpolar Deep Water intrusions,and the dynamic influences of large icebergs on regional circulation.Despite significant progress,challenges remain in integrating multi-component interactions and achieving long-term,high-resolution climate projections.Future efforts should focus on developing fully coupled models that incorporate atmosphere–ocean–sea ice–ice shelf–iceberg interactions,supported by enhanced observational networks and improved computational efficiency.This review underscores the importance of continued modeling advancement to better predict the responses of Antarctic ice shelves and polar climate to global change.
基金jointly supported by the National Natural Science Foundation of China(Grant No.42376250)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA19070402).
文摘Predicting Antarctic sea ice is of substantial academic and practical significance.However,current prediction models,including deep learning(DL)-based models,show notable bias in the marginal ice zone.In this study,we developed a pure data-driven DL model for predicting the Antarctic austral summer monthly-to-seasonal sea ice concentration(SIC)by incorporating a novel hybrid sea ice edge constraint loss function(HybridLoss).The model is referred to as ASICNet.Independent testing based on the last five years(2019–23)demonstrates that ASICNet with HybridLoss achieves significantly higher skill metrics than without,with a reduced mean absolute error of 0.021 from 0.022,a reduced integrated ice edge error of 1.714×10^(6)from 1.794×10^(6)km^(2),but an increased pattern correlation coefficient of 0.40 from 0.38,although both ASICNet versions outperform dynamical and statistical models.Furthermore,enhanced heat maps were developed to interpret the predictability sources of sea ice within DL-based models,and the results suggest that the predictability of Antarctic sea ice is attributable to factors like the Antarctic Dipole(ADP),Amundsen Sea Low(ASL),and Southern Ocean sea surface temperature(SST),as revealed in previous studies.Thus,ASICNet is an efficient tool for austral summer Antarctic SIC prediction.
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.
基金funded by the Natural Science Foundation of China(Grants No 42277127)。
文摘Rock-ice avalanches in cold high-mountain regions pose severe hazards due to their high mobility,yet the quantitative controls of particle-size ratio and ice content remain insufficiently constrained.This study investigates their coupled effects using inclinedflume experiments and Discrete Element Method(DEM)simulations,covering three gravel sizes(2-5 mm,5-7 mm,7-10 mm)and four ice-content levels(0%,20%,40%,60%).Run-out distance,velocity,energy components,flow regime(Savage number),and segregation indexαwere quantified.Increasing ice content significantly enhances mobility,but with diminishing marginal effectiveness.From 0%to 40%ice content,run-out distance increases by 41%-86%,whereas the additional increase from 40%to 60%contributes only 12%-23%.Particle-size ratio strongly governs segregation intensity.Fine-gravel groups reach segregation indices ofα=0.92-0.98,indicating nearly complete upward migration of ice,whereas medium-gravel and coarse-gravel groups exhibit much weaker segregation,stabilizing atα=0.68-0.74 and 0.60-0.69.Savage number analyses reveal marked flow-regime transitions.At 0%ice content,Savage numbers reach 1.0-1.5,indicating a collisional regime.Increasing ice content suppresses collisionality,with Savage numbers decreasing to 0.03-0.07 at 60%ice content,consistent with dense-regime flow.DEM energy analyses confirm this regime shift:for finegravel mixtures,collision energy decreases by 14%,while sliding-friction energy increases by 33%as ice content increases from 0%to 60%,reflecting enhanced overburden effects imposed by upward-segregated ice layers.Medium and coarse mixtures exhibit weaker or opposite energy-shift patterns,demonstrating strong size dependence.Mechanistically,large particle-size contrasts promote strong segregation and form dense basal rock layers that increase basal friction and reduce mobility.When particle sizes are similar or ice content is high,segregation remains limited,allowing ice to mix into the basal layer,thereby reducing basal friction and enhancing mobility.This research quantitatively demonstrates how composition controls particle spatial distribution,flow regime,and energy dissipation,offering new mechanistic insights into the propagation and deposition behaviors of rock-ice avalanches and improving hazard assessment in vulnerable high-mountain regions.
基金supported by the National Key Research and Development Program of China(Grant nos.2023YFC2809103,2024YFC2813505)the Fundamental Research Funds for the Central Universities(Grant nos.2042025kf0083,2042025gf0014)the Antarctic Zhongshan Ice and Space Environment National Observation and Research Station(Grant no.ZSNORS-20252702).
文摘The correlation between the Soil Moisture and Ocean Salinity(SMOS)L-band brightness temperature and thin sea ice thickness has been widely exploited using semi-empirical retrieval approaches based on a single-tie point(STP).However,due to pronounced spatial heterogeneity in seawater and sea ice properties across the Arctic,the use of an STP often leads to regionally biased.To address this limitation,this study proposes a multi-tie point(MTP)sea ice thickness retrieval method based on SMOS brightness temperature and sea ice concentration time series.Multiple seawater and sea ice tie-point values are identified through point-by-point time series analysis,quality control,and statistical hypothesis testing,allowing spatial variability in radiometric properties to be explicitly considered.The MTP-based retrieval is applied to Arctic freeze-up conditions.Validation against independent SMOS thin sea ice thickness products shows that the MTP approach yields significantly reduced bias and root mean square error compared with the conventional STP method,with statistically significant improvements confirmed by paired t-tests.While retrieval accuracy stabilizes beyond a certain number of tie points,the preprocessing cost associated with tie-point selection increases substantially.Considering both accuracy and efficiency,the MTP framework provides a practical and robust approach for large-scale Arctic thin sea ice thickness retrieval and enables improved characterization of regional freezing processes and maximum ice thickness.
基金supported by the National Key Research and Development Program(No.2023YFC2809101)the Laoshan Laboratory Technology Innovation Project(No.LSKJ202202301)。
文摘Arctic sea ice concentration(SIC)prediction on a subseasonal scale plays an important role in polar navigation.To reduce the high uncertainty of daily forecasts,three time series prediction models are combined with empirical orthogonal function(EOF)decomposition to forecast Arctic pentad-mean SIC,where each month is divided into six pentad-means–the first five each span five days,and the last encompasses the remaining days,which may vary in length.The models were trained on SIC data from 1989 to2018 and tested from 2019 to 2023,with lead times ranging from 1 to 12 pentad-means.Model skill was evaluated based on SIC spatial patterns,sea ice area(SIA),and the sea ice edge in September from 2019 to 2023.The moving-averaged 2-m temperature helps reduce the long short-term memory model's error in the Beaufort and Chukchi Seas.Based on the models'scores for each EOF time series,weighted ensemble prediction results were obtained.These results outperform two benchmark models across all lead times.In addition,the ensemble prediction better reproduces the seasonal cycle of the SIA,with relative errors ranging from 1.04%to 3.85%.The predicted September ice edge closely matches observations,with binary accuracy consistently above 90%.Forecast models show the lowest errors in the central Arctic,while relatively higher errors appear in the Barents and Kara Seas.
基金Project supported by the National Key R&D Program of China(Grant Nos.2021YFA1400500 and 2025YFF1502400)the National Natural Science Foundation of China(Grant Nos.92361302,12250001,12535001,and U22A20260)+3 种基金the China Postdoctoral Science Foundation(Grant Nos.BX20230021,2023T160011,and 2024M760068)support from the National Program for Support of Top-notch Young professionalssupport from Beijing Outstanding Young Scientist Program(Grant No.JWZQ20240101002)the New Cornerstone Science Foundation through the New Cornerstone Investigator Program and the XPLORER PRIZE。
文摘Ice premelting,the formation of a quasi-liquid layer on ice surfaces below the bulk melting point,plays a crucial role in various processes,ranging from glacier dynamics to ice friction and surface chemistry.Despite intensive research,the microscopic structure of the premelting layer and underlying molecular mechanisms remain poorly understood.In this work,we studied the temperature-and pressure-dependent structural disordering of crystalline Ih(0001)surface near the onset of premelting on the atomic scale by qPlus-based cryogenic atomic force microscopy.The linear correlation between the density of planar local structure(PLS)and the fraction of disordered surface region showed that the PLS mediated early-stage premelting by serving as a metastable seeding state.Notably,the associated surface disordering is cooperative,extending over an area of roughly~2 nm^(2) around a PLS.We further found a striking structural similarity between the kinetic-trapped regime below the surface crystallization temperature(T_(c))and the premelting-dominated regime above T_(c).As the deposition pressure increased,the characteristic temperature dependence was preserved,with only T_(c) shifting to higher values due to kinetic effects.Finally,we proposed a surface phase diagram for ice Ih(0001)based on our experimental observations.
文摘Ice crystal icing is an important cause of accidents in aircraft engines.Ice formation in aircraft engines can cause internal blades to freeze,affecting the quality of the air flow field and blocking the flow path.On the other hand,the entry of ice crystal particles into the combustion chamber can cause a decrease in temperature or even flameout,leading to engine surge or shutdown.Therefore,it is necessary to conduct multiphase flow tests on ice crystals for aircraft components such as aircraft engines.Conducting ice crystal multiphase flow tests on aircraft is an effective research method,but it requires the construction of an ice crystal multiphase flow test platform that meets relevant technical requirements.The paper focuses on the relevant experimental requirements and combines wind tunnel test structures to conduct multiphase flow numerical simulations on various forms of jet pipelines,obtaining particle motion distribution results.After comparison,the optimal form of jet structure is obtained,providing the best selection scheme for the design of relevant wind tunnel structures.
文摘Debate over the benefits and harms of icing acute muscle injuries remains unresolved.Some contend that ice is ineffective or even harmful,while others promote cryotherapy as a universal remedy.Centrists,often academics,call for more high-quality randomized controlled trials(RCTs)to resolve the issue.This viewpoint reframes the debate around 3 key points:first,although ice produces analgesia,evidence for sustained pain relief,beyond the immediate post-treatment period.
基金supported by the National Natural Science Foundation of China(No.41971339)the SDUST Research Fund(No.2019TDJH103)。
文摘The rapid melting of Arctic sea ice poses significant risks to the safety of shipping routes.Accurate remote sensing data on sea ice concentration(SIC)is crucial for effective route planning of ships and ensuring navigational safety.Despite the availability of numerous SIC products in China,these datasets still lag behind mainstream international products in terms of data accuracy,spatiotemporal resolution,and time span.To enhance the accuracy of China's domestic SIC remote sensing data,this study used the SIC data derived from the passive microwave remote sensing dataset provided by the University of Bremen(BRM-SIC)as a reference to conduct a comprehensive evaluation and analysis of two additional SIC datasets:the dataset derived from the microwave radiation imager(MWRI)aboard the FY-3D satellite,provided by the National Satellite Meteorological Center(FY-SIC),and the dataset obtained through the DT-ASI algorithm from the microwave imager of the FY-3D satellite,provided by Ocean University of China(OUC-SIC).Based on the evaluation results,a TransUnet fusion correction model was developed.The performance of this model was then compared against Ordinary Least Squares(OLS),Random Forest(RF),and UNet correction models,through spatial and temporal analyses.Results indicate that,compared to FY-SIC data,the RMSE of the OUC-SIC data and the standard data is reduced by24.245%,while the R is increased by 12.516%.Overall,the accuracy of OUC-SIC data is superior to that of FY-SIC data.During the research period(2020–2022),the standard deviation(SD)and coefficient of variation(CV)of OUC-SIC were 3.877%and 10.582%,respectively,while those for FY-SIC were 7.836%and 7.982%,respectively.In the study area,compared with OUC-SIC data,FYSIC data exhibited a larger standard deviation of deviation and a smaller coefficient of variation of deviation across most sea areas.These results indicate that the OUC-SIC data exhibit better temporal and spatial stability,whereas the FY-SIC data show stronger relative dimensionless stability.Among the four correction models,all showed improvements over the original,unfused corrected data.The fusion corrections using the OLS,RF,UNet,and TransUnet models reduced RMSE by 5.563%,14.601%,42.927%,and48.316%,respectively.Correspondingly,R increased by 0.463%,1.176%,3.951%,and 4.342%,respectively.Among these models,TransUnet performed the best,effectively integrating the advantages of FY-SIC and OUC-SIC data and notably improving the overall accuracy and spatiotemporal stability of SIC data.
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.
