Drought across Northwest China in late spring has exerted a vital effect on the local climate and agricultural production,and has been alleviated during the past decades.This study explored the influence of the preced...Drought across Northwest China in late spring has exerted a vital effect on the local climate and agricultural production,and has been alleviated during the past decades.This study explored the influence of the preceding Arctic sea ice on the May drought in Northwest China caused by the precipitation deficit.Further analysis indicated that when the Greenland Sea ice concentration is abnormally high during February to April,the dry conditions in Northwest China tend to be alleviated.The increase of sea ice in the Greenland Sea can excite a meridional circulation,which causes sea surface temperature(SST)anomalies in the North Atlantic via the sea-air interaction,manifested as significant warm SST anomalies over the south of Greenland and the subtropical North Atlantic,but negative SST anomalies over the west of the Azores.This abnormal SST pattern maintains to May and triggers a zonal wave train from the North Atlantic through Scandinavia and Central Asia to Northwest China,leading to abnormal cyclones in Northwest China.Consequently,Northwest China experiences a more humid climate than usual.展开更多
Purpose:The goal of this study is to analyze the relationship between funded and unfunded papers and their citations in both basic and applied sciences.Design/methodology/approach:A power law model analyzes the relati...Purpose:The goal of this study is to analyze the relationship between funded and unfunded papers and their citations in both basic and applied sciences.Design/methodology/approach:A power law model analyzes the relationship between research funding and citations of papers using 831,337 documents recorded in the Web of Science database.Findings:The original results reveal general characteristics of the diffusion of science in research fields:a)Funded articles receive higher citations compared to unfunded papers in journals;b)Funded articles exhibit a super-linear growth in citations,surpassing the increase seen in unfunded articles.This finding reveals a higher diffusion of scientific knowledge in funded articles.Moreover,c)funded articles in both basic and applied sciences demonstrate a similar expected change in citations,equivalent to about 1.23%,when the number of funded papers increases by 1%in journals.This result suggests,for the first time,that funding effect of scientific research is an invariant driver,irrespective of the nature of the basic or applied sciences.Originality/value:This evidence suggests empirical laws of funding for scientific citations that explain the importance of robust funding mechanisms for achieving impactful research outcomes in science and society.These findings here also highlight that funding for scientific research is a critical driving force in supporting citations and the dissemination of scientific knowledge in recorded documents in both basic and applied sciences.Practical implications:This comprehensive result provides a holistic view of the relationship between funding and citation performance in science to guide policymakers and R&D managers with science policies by directing funding to research in promoting the scientific development and higher diffusion of results for the progress of human society.展开更多
A shortage of courtrooms has long been a challenge in Malawi,especially since more judges were hired to help to streamline the country’s judicial process.Yet,while the current judiciary is headquartered in the countr...A shortage of courtrooms has long been a challenge in Malawi,especially since more judges were hired to help to streamline the country’s judicial process.Yet,while the current judiciary is headquartered in the country’s second-largest city of Blantyre,due to a lack of work space;some sections of the judiciary are located elsewhere,such as the juvenile,commercial and industrial courts.展开更多
As the global temperature continues to increase, the sea level continues to rise at a rapid rate that has never been seen before. This becomes an issue for many facets of life but one of the most impacted is the trans...As the global temperature continues to increase, the sea level continues to rise at a rapid rate that has never been seen before. This becomes an issue for many facets of life but one of the most impacted is the transportation infrastructure. Many people living in low elevation coastal areas can become trapped by flooding with no way in or out. With Delaware being a coastal state, this would affect a large portion of the population and will have detrimental effects over time if nothing is done to combat sea level rise. The issue with sea level rise in transportation is that once the roads become flooded, they become virtually unusable and detour routes would be needed. If all the roads in a coastal area were to be affected by sea level rise, the options for detours would become limited. This article looks at direct solutions to combat sea level rise and indirect solutions that would specifically help transportation infrastructure and evacuation routes in Delaware. There is not one solution that can fix every problem, so many solutions are laid out to see what is applicable to each affected area. Some solutions include defense structures that would be put close to the coast, raising the elevation of vulnerable roads throughout the state and including pumping stations to drain the water on the surface of the road. With an understanding of all these solutions around the world, the ultimate conclusion came in the form of a six-step plan that Delaware should take in order to best design against sea level rise in these coastal areas.展开更多
[Objective]The aim was to provide scientific basis for the prevention and treatment of the main diseases and pests. [Method]The systematic investigation was carried out in the process of seedling and field cultivation...[Objective]The aim was to provide scientific basis for the prevention and treatment of the main diseases and pests. [Method]The systematic investigation was carried out in the process of seedling and field cultivation of Ligusticum chuanxiong. [Result]The main diseases were root rot,Powdery mildew and Spot blight,while the main pests were Epinotia leucantha Meyrick,Prodenia litura Fabr.,Scarabaeoidea,Tetranychus cinnabarinus Boisduval and Delia platura Meigen. [Conclusion]The law of occurrence of main diseases and pests were confirmed.展开更多
The article systematically summarizes the pathogen, incidence law and disease symptom of rice blast, and raises the integrated control technique for the disease, which will provide the certain theoretical basis for th...The article systematically summarizes the pathogen, incidence law and disease symptom of rice blast, and raises the integrated control technique for the disease, which will provide the certain theoretical basis for the control of the disease, being benefit for the actual production of rice in field.展开更多
The conceptions of theorems, laws and corollaries of hydrology were put forward. Combining with hydrology practice, several theo- rems, laws as well as corollaries of hydrology were summarized. The study provided some...The conceptions of theorems, laws and corollaries of hydrology were put forward. Combining with hydrology practice, several theo- rems, laws as well as corollaries of hydrology were summarized. The study provided some references for accelerating the development of hydrology theory in these aspects and promoting the improvement of its production technology.展开更多
[Objective] The aim is to investigate the impact of different host plants, planting methods and directions on the damage law of Asterococcus muratae. [Method] The quantity of pests, size of female pests and quantity o...[Objective] The aim is to investigate the impact of different host plants, planting methods and directions on the damage law of Asterococcus muratae. [Method] The quantity of pests, size of female pests and quantity of ova of A. mu-ratae in Suzhou in different host plants under two planting methods and in four di-rections of a host plant were measured. [Result] A. muratae exhibits selectivity to host plants, and their quantity, female pest size and reproductive capacity are higher in Magnolia grandiflora(southern magnolia) than in other plants. The four directions of the host plant suffer to different extents, and the north part is usual y the most in-jured. Mass-planted southern magnolias are more seriously impacted than individual y-planted ones. Both size and weight of a female pest have significant linear relations with ovum quantity, and the weight of a female pest is more closely related to its ovum quantity. Based on the weight of a female pest, we can predict the exact ovum quantity according to the equation y=2E-05x+0.003 7. [Conclusion] The research re-sults provide reference for making an effective control plan for A. muratae.展开更多
In this study,the structural characters,antioxidant activities and bile acid-binding ability of sea buckthorn polysaccharides(HRPs)obtained by the commonly used hot water(HRP-W),pressurized hot water(HRP-H),ultrasonic...In this study,the structural characters,antioxidant activities and bile acid-binding ability of sea buckthorn polysaccharides(HRPs)obtained by the commonly used hot water(HRP-W),pressurized hot water(HRP-H),ultrasonic(HRP-U),acid(HRP-C)and alkali(HRP-A)assisted extraction methods were investigated.The results demonstrated that extraction methods had significant effects on extraction yield,monosaccharide composition,molecular weight,particle size,triple-helical structure,and surface morphology of HRPs except for the major linkage bands.Thermogravimetric analysis showed that HRP-U with filamentous reticular microstructure exhibited better thermal stability.The HRP-A with the lowest molecular weight and highest arabinose content possessed the best antioxidant activities.Moreover,the rheological analysis indicated that HRPs with higher galacturonic acid content and molecular weight showed higher viscosity and stronger crosslinking network(HRP-C,HRP-W and HRP-U),which exhibited stronger bile acid binding capacity.The present findings provide scientific evidence in the preparation technology of sea buckthorn polysaccharides with good antioxidant and bile acid binding capacity which are related to the structure affected by the extraction methods.展开更多
The Pearl River Delta(PRD),a tornado hotspot,forms a distinct trumpet-shaped coastline that concaves toward the South China Sea.During the summer monsoon season,low-level southwesterlies over the PRD’s sea surface te...The Pearl River Delta(PRD),a tornado hotspot,forms a distinct trumpet-shaped coastline that concaves toward the South China Sea.During the summer monsoon season,low-level southwesterlies over the PRD’s sea surface tend to be turned toward the west coast,constituting a convergent wind field along with the landward-side southwesterlies,which influences regional convective weather.This two-part study explores the roles of this unique land–sea contrast of the trumpet-shaped coastline in the formation of a tornadic mesovortex within monsoonal flows in this region.Part I primarily presents observational analyses of pre-storm environments and storm evolutions.The rotating storm developed in a lowshear environment(not ideal for a supercell)under the interactions of three air masses under the influence of the land–sea contrast,monsoon,and storm cold outflows.This intersection zone(or“triple point”)is typically characterized by local enhancements of ambient vertical vorticity and convergence.Based on a rapid-scan X-band phased-array radar,finger-like echoes were recognized shortly after the gust front intruded on the triple point.Developed over the triple point,they rapidly wrapped up with a well-defined low-level mesovortex.It is thus presumed that the triple point may have played roles in the mesovortex genesis,which will be demonstrated in Part II with multiple sensitivity numerical simulations.The findings also suggest that when storms pass over the boundary intersection zone in the PRD,the expected possibility of a rotating storm occurring is relatively high,even in a low-shear environment.Improved knowledge of such environments provides additional guidance to assess the regional tornado risk.展开更多
In recent years,deep learning methods have gradually been applied to prediction tasks related to Arctic sea ice concentration,but relatively little research has been conducted for larger spatial and temporal scales,ma...In recent years,deep learning methods have gradually been applied to prediction tasks related to Arctic sea ice concentration,but relatively little research has been conducted for larger spatial and temporal scales,mainly due to the limited time coverage of observations and reanalysis data.Meanwhile,deep learning predictions of sea ice thickness(SIT)have yet to receive ample attention.In this study,two data-driven deep learning(DL)models are built based on the ConvLSTM and fully convolutional U-net(FC-Unet)algorithms and trained using CMIP6 historical simulations for transfer learning and fine-tuned using reanalysis/observations.These models enable monthly predictions of Arctic SIT without considering the complex physical processes involved.Through comprehensive assessments of prediction skills by season and region,the results suggest that using a broader set of CMIP6 data for transfer learning,as well as incorporating multiple climate variables as predictors,contribute to better prediction results,although both DL models can effectively predict the spatiotemporal features of SIT anomalies.Regarding the predicted SIT anomalies of the FC-Unet model,the spatial correlations with reanalysis reach an average level of 89%over all months,while the temporal anomaly correlation coefficients are close to unity in most cases.The models also demonstrate robust performances in predicting SIT and SIE during extreme events.The effectiveness and reliability of the proposed deep transfer learning models in predicting Arctic SIT can facilitate more accurate pan-Arctic predictions,aiding climate change research and real-time business applications.展开更多
The shrinking Arctic sea-ice area(SIA) in recent decades is a striking manifestation of the ongoing climate change.Variations of the Arctic sea ice have been continuously observed by satellites since 1979, relatively ...The shrinking Arctic sea-ice area(SIA) in recent decades is a striking manifestation of the ongoing climate change.Variations of the Arctic sea ice have been continuously observed by satellites since 1979, relatively well monitored since the 1950s, but are highly uncertain in the earlier period due to a lack of observations. Several reconstructions of the historical gridded sea-ice concentration(SIC) data were recently presented based on synthesized regional sea-ice observations or by applying a hybrid model–empirical approach. Here, we present an SIC reconstruction for the period1901–2019 based on established co-variability between SIC and surface air temperature, sea surface temperature, and sea level pressure patterns. The reconstructed sea-ice data for March and September are compared to the frequently used Had ISST1.1 and SIBT1850 datasets. Our reconstruction shows a large decrease in SIA from the 1920 to 1940 concurrent with the Early 20th Century Warming event in the Arctic. Such a negative SIA anomaly is absent in Had ISST1.1 data. The amplitude of the SIA anomaly reaches about 0.8 mln km^(2) in March and 1.5 mln km^(2) in September. The anomaly is about three times stronger than that in the SIBT1850 dataset. The larger decrease in SIA in September is largely due to the stronger SIC reduction in the western sector of the Arctic Ocean in the 70°–80°N latitudinal zone. Our reconstruction provides gridded monthly data that can be used as boundary conditions for atmospheric reanalyses and model experiments to study the Arctic climate for the first half of the 20th century.展开更多
High-resolution sea-level data and high-precision dating of corals in the northern South China Sea(SCS)during the Holocene provide a reference and historical background for current and future sea-level changes and a b...High-resolution sea-level data and high-precision dating of corals in the northern South China Sea(SCS)during the Holocene provide a reference and historical background for current and future sea-level changes and a basis for scientific assessment of the evolutionary trend of coral reefs in the SCS.Although sporadic studies have been performed around Hainan Island in the northern SCS,the reconstructed sea level presents different values or is controversial because the indicative meaning of the sea-level indicators were neither quantified nor uniform criteria.Here,we determined the quantitative relationship between modern living coral and sea level by measuring the top surfaces of 27 live Porites corals from the inner reef flat along the east coast of Hainan Island and assessed the accuracy of results obtained using coral as sea-level indicators.Additionally,three in situ fossil Porites corals were analyzed based on elevation measurements,digital X-ray radiography,and U-Th dating.The survey results showed that the indicative meanings for the modern live Porites corals is(146.09±8.35)cm below the mean tide level(MTL).It suggested that their upward growth limit is constrained by the sea level,and the lowest low water is the highest level of survival for the modern live Porites corals.Based on the newly defined indicative meanings,6 new sea-level index points(SLIPs)were obtained and 19 published SLIPs were recalculated.Those SLIPs indicated a relative sea level fluctuation between(227.7±9.8)cm to(154.88±9.8)cm MTL between(5393±25)cal a BP and(3390±12)cal a BP,providing evidences of the Mid-Holocene sea-level highstand in the northern SCS.Besides that,our analysis demonstrated that different sea-level histories may be produced based on different indicative meanings or criteria.The dataset of 276 coral U-Th ages indicates that coral reef development in the northern SCS comprised the initial development,boom growth,decline,and flourishing development again.A comparison with regional records indicated that synergistic effects of climatic and environmental factors were involved in the development of coral reefs in the northern SCS.Thus,the cessation of coral reef development during the Holocene in the northern SCS was probably associated with the dry and cold climate in South China,as reflected in the synchronous weakening of the ENSO and East Asian summer monsoon induced by the reduction of the 65°N summer insolation,which forced the migration of the Intertropical Convergence Zone.展开更多
In recent years,the exploration of seabed has been intensified,but the submarine soils of silt and sand in the Yellow Sea area have not been well investigated so far.In this study,the physical and mechanical propertie...In recent years,the exploration of seabed has been intensified,but the submarine soils of silt and sand in the Yellow Sea area have not been well investigated so far.In this study,the physical and mechanical properties of silt and sand from the Yellow Sea were measured using a direct shear apparatus and their microstructures were observed using a scanning electron microscope.The test results suggest that the shear strength of silt and sand increases linearly with the increase of normal stress.Based on the direct shear test,the scanning electron microscope was used to observe the section surface of sand.It is observed that the section surface becomes rough,with many“V”‐shaped cracks.Many particles appear on the surface of the silt structure and tend to be disintegrated.The X‐ray diffraction experiment reveals that the sand and silt have different compositions.The shear strength of sand is slightly greater than that of silt under high stress,which is related to the shape of soil particles and the mineral composition.These results can be a reference for further study of other soils in the Yellow Sea;meanwhile,they can serve as soil parameters for the stability and durability analyses of offshore infrastructure construction.展开更多
The academic world is still uncertain about the classification of Taisui. It is debating whether Taisui is living or not, myxomycete complex or fungi. The passage studies the 228 finding reports of Taisui in modern Ch...The academic world is still uncertain about the classification of Taisui. It is debating whether Taisui is living or not, myxomycete complex or fungi. The passage studies the 228 finding reports of Taisui in modern China. It confirms that the first finding time of Taisui in modern China is 1963, and the first reported time is 1992. Taisui has been found in 25 administrative divisions. Taisui occurs the most times in Shandong Province. Besides, provinces where Taisui has been found most times are in northern China. Finding locations of Taisui vary from place to place. Taisui is most often found in normal earth layer, with different burying depth. Taisui is mainly found through seeing, tramping, and digging. Taisui findings lack subjective motivations and are connected with the life and production of the finders. Conclusion: Taisui is an object growing in earth layer.展开更多
The Aral Sea was the fourth largest lake in the world but it has shrunk dramatically as a result of irrational human activities, triggering the "Aral Sea ecological crisis". The ecological problems of the Ar...The Aral Sea was the fourth largest lake in the world but it has shrunk dramatically as a result of irrational human activities, triggering the "Aral Sea ecological crisis". The ecological problems of the Aral Sea have attracted widespread attention, and the alleviation of the Aral Sea ecological crisis has reached a consensus among the five Central Asian countries(Kazakhstan, Uzbekistan, Tajikistan, Kyrgyzstan, and Turkmenistan). In the past decades, many ecological management measures have been implemented for the ecological restoration of the Aral Sea. However, due to the lack of regional planning and zoning, the results are not ideal. In this study, we mapped the ecological zoning of the Aral Sea from the perspective of ecological restoration based on soil type, soil salinity, surface water, groundwater table, Normalized Difference Vegetation Index(NDVI), land cover, and aerosol optical depth(AOD) data. Soil salinization and salt dust are the most prominent ecological problems in the Aral Sea. We divided the Aral Sea into 7 first-level ecological restoration subregions(North Aral Sea catchment area in the downstream of the Syr Darya River(Subregion Ⅰ);artificial flood overflow area in the downstream of the Aral Sea(Subregion Ⅱ);physical/chemical remediation area of the salt dust source area in the eastern part of the South Aral Sea(Subregion Ⅲ);physical/chemical remediation area of severe salinization in the central part of the South Aral Sea(Subregion Ⅳ);existing water surface and potential restoration area of the South Aral Sea(Subregion Ⅴ);Aral Sea vegetation natural recovery area(Subregion Ⅵ);and vegetation planting area with slight salinization in the South Aral Sea(Subregion Ⅶ)) and 14 second-level ecological restoration subregions according to the ecological zoning principles. Implementable measures are proposed for each ecological restoration subregion. For Subregion Ⅰ and Subregion Ⅱ with lower elevations, artificial flooding should be carried out to restore the surface of the Aral Sea. Subregion Ⅲ and Subregion Ⅳ have severe salinization, making it difficult for vegetation to grow. In these subregions, it is recommended to cover and pave the areas with green biomatrix coverings and environmentally sustainable bonding materials. In Subregion Ⅴ located in the central and western parts of the South Aral Sea, surface water recharge should be increased to ensure that this subregion can maintain normal water levels. In Subregion Ⅵ and Subregion Ⅶ where natural conditions are suitable for vegetation growth, measures such as afforestation and buffer zones should be implemented to protect vegetation. This study could provide a reference basis for future comprehensive ecological management and restoration of the Aral Sea.展开更多
Many locations with concentrated hydrates at vents have confirmed the presence of abundant thermogenic gas in the middle of the Qiongdongnan Basin(QDNB).However,the impact of deep structures on gasbearing fluids migra...Many locations with concentrated hydrates at vents have confirmed the presence of abundant thermogenic gas in the middle of the Qiongdongnan Basin(QDNB).However,the impact of deep structures on gasbearing fluids migration and gas hydrates distribution in tectonically inactive regions is still unclear.In this study,the authors apply high-resolution 3D seismic and logging while drilling(LWD)data from the middle of the QDNB to investigate the influence of deep-large faults on gas chimneys and preferred gasescape pipes.The findings reveal the following:(1)Two significant deep-large faults,F1 and F2,developed on the edge of the Songnan Low Uplift,control the dominant migration of thermogenic hydrocarbons and determine the initial locations of gas chimneys.(2)The formation of gas chimneys is likely related to fault activation and reactivation.Gas chimney 1 is primarily arises from convergent fluid migration resulting from the intersection of the two faults,while the gas chimney 2 benefits from a steeper fault plane and shorter migration distance of fault F2.(3)Most gas-escape pipes are situated near the apex of the two faults.Their reactivations facilitate free gas flow into the GHSZ and contribute to the formation of fracture‐filling hydrates.展开更多
To quantify the relative contributions of Arctic sea ice and unforced atmospheric internal variability to the “warm Arctic, cold East Asia”(WACE) teleconnection, this study analyses three sets of large-ensemble simu...To quantify the relative contributions of Arctic sea ice and unforced atmospheric internal variability to the “warm Arctic, cold East Asia”(WACE) teleconnection, this study analyses three sets of large-ensemble simulations carried out by the Norwegian Earth System Model with a coupled atmosphere–land surface model, forced by seasonal sea ice conditions from preindustrial, present-day, and future periods. Each ensemble member within the same set uses the same forcing but with small perturbations to the atmospheric initial state. Hence, the difference between the present-day(or future) ensemble mean and the preindustrial ensemble mean provides the ice-loss-induced response, while the difference of the individual members within the present-day(or future) set is the effect of atmospheric internal variability. Results indicate that both present-day and future sea ice loss can force a negative phase of the Arctic Oscillation with a WACE pattern in winter. The magnitude of ice-induced Arctic warming is over four(ten) times larger than the ice-induced East Asian cooling in the present-day(future) experiment;the latter having a magnitude that is about 30% of the observed cooling. Sea ice loss contributes about 60%(80%) to the Arctic winter warming in the present-day(future) experiment. Atmospheric internal variability can also induce a WACE pattern with comparable magnitudes between the Arctic and East Asia. Ice-lossinduced East Asian cooling can easily be masked by atmospheric internal variability effects because random atmospheric internal variability may induce a larger magnitude warming. The observed WACE pattern occurs as a result of both Arctic sea ice loss and atmospheric internal variability, with the former dominating Arctic warming and the latter dominating East Asian cooling.展开更多
Considering the danger of water inrush in mining very thick coal seam under water-rich roof in Majialiang Coal Mine,the universal discrete element(UDEC)software was used to simulate the overburden fracture evolution l...Considering the danger of water inrush in mining very thick coal seam under water-rich roof in Majialiang Coal Mine,the universal discrete element(UDEC)software was used to simulate the overburden fracture evolution laws when mining 4#coal seam.Besides,this study researched on the influence of face advancing length,speed and mining height on the height of the water flowing fractured zones(HWFFZ),and analyzed the correlation of face advancing length and change rules of aquifer water levels and goaf water inflow.Based on those mentioned above,this research proposed the following water-controlling technologies:draining the roof water before mining,draining goaf water,reasonable advancing speed and mining thickness.These water-controlling technologies were successfully used in the feld,thus ensured safely mining the very thick coal seam under water-rich roof.展开更多
Arctic sea ice is broadly regarded as an indicator and amplifier of global climate change.The rapid changes in Arctic sea ice have been widely concerned.However,the spatiotemporal changes in the horizontal and vertica...Arctic sea ice is broadly regarded as an indicator and amplifier of global climate change.The rapid changes in Arctic sea ice have been widely concerned.However,the spatiotemporal changes in the horizontal and vertical dimensions of Arctic sea ice and its asymmetry during the melt and freeze seasons are rarely quantified simultaneously based on multiple sources of the same long time series.In this study,the spatiotemporal variation and freeze-thaw asymmetry of Arctic sea ice were investigated from both the horizontal and vertical dimensions during 1979–2020 based on remote sensing and assimilation data.The results indicated that Arctic sea ice was declining at a remarkably high rate of–5.4×10^(4) km^(2)/a in sea ice area(SIA)and–2.2 cm/a in sea ice thickness(SIT)during 1979 to 2020,and the reduction of SIA and SIT was the largest in summer and the smallest in winter.Spatially,compared with other sub-regions,SIA showed a sharper declining trend in the Barents Sea,Kara Sea,and East Siberian Sea,while SIT presented a larger downward trend in the northern Canadian Archipelago,northern Greenland,and the East Siberian Sea.Regarding to the seasonal trend of sea ice on sub-region scale,the reduction rate of SIA exhibited an apparent spatial heterogeneity among seasons,especially in summer and winter,i.e.,the sub-regions linked to the open ocean exhibited a higher decline rate in winter;however,the other sub-regions blocked by the coastlines presented a greater decline rate in summer.For SIT,the sub-regions such as the Beaufort Sea,East Siberian Sea,Chukchi Sea,Central Arctic,and Canadian Archipelago always showed a higher downward rate in all seasons.Furthermore,a striking freeze-thaw asymmetry of Arctic sea ice was also detected.Comparing sea ice changes in different dimensions,sea ice over most regions in the Arctic showed an early retreat and rapid advance in the horizontal dimension but late melting and gradual freezing in the vertical dimension.The amount of sea ice melting and freezing was disequilibrium in the Arctic during the considered period,and the rate of sea ice melting was 0.3×10^(4) km^(2)/a and 0.01 cm/a higher than that of freezing in the horizontal and vertical dimensions,respectively.Moreover,there were notable shifts in the melting and freezing of Arctic sea ice in 1997/2003 and 2000/2004,respectively,in the horizontal/vertical dimension.展开更多
基金supported by the National Natural Science Foun-dation of China [grant numbers 41991281 and 42005028]。
文摘Drought across Northwest China in late spring has exerted a vital effect on the local climate and agricultural production,and has been alleviated during the past decades.This study explored the influence of the preceding Arctic sea ice on the May drought in Northwest China caused by the precipitation deficit.Further analysis indicated that when the Greenland Sea ice concentration is abnormally high during February to April,the dry conditions in Northwest China tend to be alleviated.The increase of sea ice in the Greenland Sea can excite a meridional circulation,which causes sea surface temperature(SST)anomalies in the North Atlantic via the sea-air interaction,manifested as significant warm SST anomalies over the south of Greenland and the subtropical North Atlantic,but negative SST anomalies over the west of the Azores.This abnormal SST pattern maintains to May and triggers a zonal wave train from the North Atlantic through Scandinavia and Central Asia to Northwest China,leading to abnormal cyclones in Northwest China.Consequently,Northwest China experiences a more humid climate than usual.
文摘Purpose:The goal of this study is to analyze the relationship between funded and unfunded papers and their citations in both basic and applied sciences.Design/methodology/approach:A power law model analyzes the relationship between research funding and citations of papers using 831,337 documents recorded in the Web of Science database.Findings:The original results reveal general characteristics of the diffusion of science in research fields:a)Funded articles receive higher citations compared to unfunded papers in journals;b)Funded articles exhibit a super-linear growth in citations,surpassing the increase seen in unfunded articles.This finding reveals a higher diffusion of scientific knowledge in funded articles.Moreover,c)funded articles in both basic and applied sciences demonstrate a similar expected change in citations,equivalent to about 1.23%,when the number of funded papers increases by 1%in journals.This result suggests,for the first time,that funding effect of scientific research is an invariant driver,irrespective of the nature of the basic or applied sciences.Originality/value:This evidence suggests empirical laws of funding for scientific citations that explain the importance of robust funding mechanisms for achieving impactful research outcomes in science and society.These findings here also highlight that funding for scientific research is a critical driving force in supporting citations and the dissemination of scientific knowledge in recorded documents in both basic and applied sciences.Practical implications:This comprehensive result provides a holistic view of the relationship between funding and citation performance in science to guide policymakers and R&D managers with science policies by directing funding to research in promoting the scientific development and higher diffusion of results for the progress of human society.
文摘A shortage of courtrooms has long been a challenge in Malawi,especially since more judges were hired to help to streamline the country’s judicial process.Yet,while the current judiciary is headquartered in the country’s second-largest city of Blantyre,due to a lack of work space;some sections of the judiciary are located elsewhere,such as the juvenile,commercial and industrial courts.
文摘As the global temperature continues to increase, the sea level continues to rise at a rapid rate that has never been seen before. This becomes an issue for many facets of life but one of the most impacted is the transportation infrastructure. Many people living in low elevation coastal areas can become trapped by flooding with no way in or out. With Delaware being a coastal state, this would affect a large portion of the population and will have detrimental effects over time if nothing is done to combat sea level rise. The issue with sea level rise in transportation is that once the roads become flooded, they become virtually unusable and detour routes would be needed. If all the roads in a coastal area were to be affected by sea level rise, the options for detours would become limited. This article looks at direct solutions to combat sea level rise and indirect solutions that would specifically help transportation infrastructure and evacuation routes in Delaware. There is not one solution that can fix every problem, so many solutions are laid out to see what is applicable to each affected area. Some solutions include defense structures that would be put close to the coast, raising the elevation of vulnerable roads throughout the state and including pumping stations to drain the water on the surface of the road. With an understanding of all these solutions around the world, the ultimate conclusion came in the form of a six-step plan that Delaware should take in order to best design against sea level rise in these coastal areas.
基金Supported by National Key Technology R&D Program(2006BAI09B04-05)Sichuan Youth Science and Technology Foundation (09ZQ026-039)Foundation for Excellent Science and Technology Papers of Sichuan Academy of Agricultural Science~~
文摘[Objective]The aim was to provide scientific basis for the prevention and treatment of the main diseases and pests. [Method]The systematic investigation was carried out in the process of seedling and field cultivation of Ligusticum chuanxiong. [Result]The main diseases were root rot,Powdery mildew and Spot blight,while the main pests were Epinotia leucantha Meyrick,Prodenia litura Fabr.,Scarabaeoidea,Tetranychus cinnabarinus Boisduval and Delia platura Meigen. [Conclusion]The law of occurrence of main diseases and pests were confirmed.
文摘The article systematically summarizes the pathogen, incidence law and disease symptom of rice blast, and raises the integrated control technique for the disease, which will provide the certain theoretical basis for the control of the disease, being benefit for the actual production of rice in field.
文摘The conceptions of theorems, laws and corollaries of hydrology were put forward. Combining with hydrology practice, several theo- rems, laws as well as corollaries of hydrology were summarized. The study provided some references for accelerating the development of hydrology theory in these aspects and promoting the improvement of its production technology.
文摘[Objective] The aim is to investigate the impact of different host plants, planting methods and directions on the damage law of Asterococcus muratae. [Method] The quantity of pests, size of female pests and quantity of ova of A. mu-ratae in Suzhou in different host plants under two planting methods and in four di-rections of a host plant were measured. [Result] A. muratae exhibits selectivity to host plants, and their quantity, female pest size and reproductive capacity are higher in Magnolia grandiflora(southern magnolia) than in other plants. The four directions of the host plant suffer to different extents, and the north part is usual y the most in-jured. Mass-planted southern magnolias are more seriously impacted than individual y-planted ones. Both size and weight of a female pest have significant linear relations with ovum quantity, and the weight of a female pest is more closely related to its ovum quantity. Based on the weight of a female pest, we can predict the exact ovum quantity according to the equation y=2E-05x+0.003 7. [Conclusion] The research re-sults provide reference for making an effective control plan for A. muratae.
基金The Guangdong Basic and Applied Basic Research Foundation(2022A1515010730)National Natural Science Foundation of China(32001647)+2 种基金National Natural Science Foundation of China(31972022)Financial and moral assistance supported by the Guangdong Basic and Applied Basic Research Foundation(2019A1515011996)111 Project(B17018)。
文摘In this study,the structural characters,antioxidant activities and bile acid-binding ability of sea buckthorn polysaccharides(HRPs)obtained by the commonly used hot water(HRP-W),pressurized hot water(HRP-H),ultrasonic(HRP-U),acid(HRP-C)and alkali(HRP-A)assisted extraction methods were investigated.The results demonstrated that extraction methods had significant effects on extraction yield,monosaccharide composition,molecular weight,particle size,triple-helical structure,and surface morphology of HRPs except for the major linkage bands.Thermogravimetric analysis showed that HRP-U with filamentous reticular microstructure exhibited better thermal stability.The HRP-A with the lowest molecular weight and highest arabinose content possessed the best antioxidant activities.Moreover,the rheological analysis indicated that HRPs with higher galacturonic acid content and molecular weight showed higher viscosity and stronger crosslinking network(HRP-C,HRP-W and HRP-U),which exhibited stronger bile acid binding capacity.The present findings provide scientific evidence in the preparation technology of sea buckthorn polysaccharides with good antioxidant and bile acid binding capacity which are related to the structure affected by the extraction methods.
基金supported by the Guangdong Major Project of Basic and Applied Basic Research(Grant No.2020B0301030004)the National Natural Science Foundation of China(Grant Nos.42275006 and 42030604)+1 种基金the Guangdong Basic and Applied Basic Research Foundation(Grant No.2023A1515011705)the Science and Technology Research Project for Society of Foshan(Grant No.2120001008761).
文摘The Pearl River Delta(PRD),a tornado hotspot,forms a distinct trumpet-shaped coastline that concaves toward the South China Sea.During the summer monsoon season,low-level southwesterlies over the PRD’s sea surface tend to be turned toward the west coast,constituting a convergent wind field along with the landward-side southwesterlies,which influences regional convective weather.This two-part study explores the roles of this unique land–sea contrast of the trumpet-shaped coastline in the formation of a tornadic mesovortex within monsoonal flows in this region.Part I primarily presents observational analyses of pre-storm environments and storm evolutions.The rotating storm developed in a lowshear environment(not ideal for a supercell)under the interactions of three air masses under the influence of the land–sea contrast,monsoon,and storm cold outflows.This intersection zone(or“triple point”)is typically characterized by local enhancements of ambient vertical vorticity and convergence.Based on a rapid-scan X-band phased-array radar,finger-like echoes were recognized shortly after the gust front intruded on the triple point.Developed over the triple point,they rapidly wrapped up with a well-defined low-level mesovortex.It is thus presumed that the triple point may have played roles in the mesovortex genesis,which will be demonstrated in Part II with multiple sensitivity numerical simulations.The findings also suggest that when storms pass over the boundary intersection zone in the PRD,the expected possibility of a rotating storm occurring is relatively high,even in a low-shear environment.Improved knowledge of such environments provides additional guidance to assess the regional tornado risk.
基金supported by the National Natural Science Foundation of China(Grant Nos.41976193 and 42176243).
文摘In recent years,deep learning methods have gradually been applied to prediction tasks related to Arctic sea ice concentration,but relatively little research has been conducted for larger spatial and temporal scales,mainly due to the limited time coverage of observations and reanalysis data.Meanwhile,deep learning predictions of sea ice thickness(SIT)have yet to receive ample attention.In this study,two data-driven deep learning(DL)models are built based on the ConvLSTM and fully convolutional U-net(FC-Unet)algorithms and trained using CMIP6 historical simulations for transfer learning and fine-tuned using reanalysis/observations.These models enable monthly predictions of Arctic SIT without considering the complex physical processes involved.Through comprehensive assessments of prediction skills by season and region,the results suggest that using a broader set of CMIP6 data for transfer learning,as well as incorporating multiple climate variables as predictors,contribute to better prediction results,although both DL models can effectively predict the spatiotemporal features of SIT anomalies.Regarding the predicted SIT anomalies of the FC-Unet model,the spatial correlations with reanalysis reach an average level of 89%over all months,while the temporal anomaly correlation coefficients are close to unity in most cases.The models also demonstrate robust performances in predicting SIT and SIE during extreme events.The effectiveness and reliability of the proposed deep transfer learning models in predicting Arctic SIT can facilitate more accurate pan-Arctic predictions,aiding climate change research and real-time business applications.
基金partly supported by the Russian Ministry of Science and Higher Education (Agreement No.075-15-2021-577)the Russian Science Foundation (Grant No.23-47-00104)+2 种基金funded by the Research Council of Norway (Grant No.Combined 328935)the support of the Bjerknes Climate Prediction Unit with funding from the Trond Mohn Foundation (Grant No.BFS2018TMT01)the support of the National Natural Science Foundation of China (Grant No.42261134532)。
文摘The shrinking Arctic sea-ice area(SIA) in recent decades is a striking manifestation of the ongoing climate change.Variations of the Arctic sea ice have been continuously observed by satellites since 1979, relatively well monitored since the 1950s, but are highly uncertain in the earlier period due to a lack of observations. Several reconstructions of the historical gridded sea-ice concentration(SIC) data were recently presented based on synthesized regional sea-ice observations or by applying a hybrid model–empirical approach. Here, we present an SIC reconstruction for the period1901–2019 based on established co-variability between SIC and surface air temperature, sea surface temperature, and sea level pressure patterns. The reconstructed sea-ice data for March and September are compared to the frequently used Had ISST1.1 and SIBT1850 datasets. Our reconstruction shows a large decrease in SIA from the 1920 to 1940 concurrent with the Early 20th Century Warming event in the Arctic. Such a negative SIA anomaly is absent in Had ISST1.1 data. The amplitude of the SIA anomaly reaches about 0.8 mln km^(2) in March and 1.5 mln km^(2) in September. The anomaly is about three times stronger than that in the SIBT1850 dataset. The larger decrease in SIA in September is largely due to the stronger SIC reduction in the western sector of the Arctic Ocean in the 70°–80°N latitudinal zone. Our reconstruction provides gridded monthly data that can be used as boundary conditions for atmospheric reanalyses and model experiments to study the Arctic climate for the first half of the 20th century.
基金The National Natural Science Foundation of China under contract Nos 42366002 and 41702182the National Key R&D Program of China under contract No.2017YFA0603300the Guangxi Scientific Projects under contract No.2018GXNSFAA281293。
文摘High-resolution sea-level data and high-precision dating of corals in the northern South China Sea(SCS)during the Holocene provide a reference and historical background for current and future sea-level changes and a basis for scientific assessment of the evolutionary trend of coral reefs in the SCS.Although sporadic studies have been performed around Hainan Island in the northern SCS,the reconstructed sea level presents different values or is controversial because the indicative meaning of the sea-level indicators were neither quantified nor uniform criteria.Here,we determined the quantitative relationship between modern living coral and sea level by measuring the top surfaces of 27 live Porites corals from the inner reef flat along the east coast of Hainan Island and assessed the accuracy of results obtained using coral as sea-level indicators.Additionally,three in situ fossil Porites corals were analyzed based on elevation measurements,digital X-ray radiography,and U-Th dating.The survey results showed that the indicative meanings for the modern live Porites corals is(146.09±8.35)cm below the mean tide level(MTL).It suggested that their upward growth limit is constrained by the sea level,and the lowest low water is the highest level of survival for the modern live Porites corals.Based on the newly defined indicative meanings,6 new sea-level index points(SLIPs)were obtained and 19 published SLIPs were recalculated.Those SLIPs indicated a relative sea level fluctuation between(227.7±9.8)cm to(154.88±9.8)cm MTL between(5393±25)cal a BP and(3390±12)cal a BP,providing evidences of the Mid-Holocene sea-level highstand in the northern SCS.Besides that,our analysis demonstrated that different sea-level histories may be produced based on different indicative meanings or criteria.The dataset of 276 coral U-Th ages indicates that coral reef development in the northern SCS comprised the initial development,boom growth,decline,and flourishing development again.A comparison with regional records indicated that synergistic effects of climatic and environmental factors were involved in the development of coral reefs in the northern SCS.Thus,the cessation of coral reef development during the Holocene in the northern SCS was probably associated with the dry and cold climate in South China,as reflected in the synchronous weakening of the ENSO and East Asian summer monsoon induced by the reduction of the 65°N summer insolation,which forced the migration of the Intertropical Convergence Zone.
基金Natural Science Foundation of Jiangsu Province,Grant/Award Number:BK20210527National Natural Science Foundation of China,Grant/Award Number:42107158Training Program for Innovation and Entrepreneurship,China University of Mining and Technology。
文摘In recent years,the exploration of seabed has been intensified,but the submarine soils of silt and sand in the Yellow Sea area have not been well investigated so far.In this study,the physical and mechanical properties of silt and sand from the Yellow Sea were measured using a direct shear apparatus and their microstructures were observed using a scanning electron microscope.The test results suggest that the shear strength of silt and sand increases linearly with the increase of normal stress.Based on the direct shear test,the scanning electron microscope was used to observe the section surface of sand.It is observed that the section surface becomes rough,with many“V”‐shaped cracks.Many particles appear on the surface of the silt structure and tend to be disintegrated.The X‐ray diffraction experiment reveals that the sand and silt have different compositions.The shear strength of sand is slightly greater than that of silt under high stress,which is related to the shape of soil particles and the mineral composition.These results can be a reference for further study of other soils in the Yellow Sea;meanwhile,they can serve as soil parameters for the stability and durability analyses of offshore infrastructure construction.
文摘The academic world is still uncertain about the classification of Taisui. It is debating whether Taisui is living or not, myxomycete complex or fungi. The passage studies the 228 finding reports of Taisui in modern China. It confirms that the first finding time of Taisui in modern China is 1963, and the first reported time is 1992. Taisui has been found in 25 administrative divisions. Taisui occurs the most times in Shandong Province. Besides, provinces where Taisui has been found most times are in northern China. Finding locations of Taisui vary from place to place. Taisui is most often found in normal earth layer, with different burying depth. Taisui is mainly found through seeing, tramping, and digging. Taisui findings lack subjective motivations and are connected with the life and production of the finders. Conclusion: Taisui is an object growing in earth layer.
基金supported by the Key R&D Program of Xinjiang Uygur Autonomous Region,China(2022B03021)the Strategic Priority Research Program of Chinese Academy of Sciences(XDA20030101)the Tianshan Talent Training Program of Xinjiang Uygur Autonomous Region,China(2022TSYCLJ0011).
文摘The Aral Sea was the fourth largest lake in the world but it has shrunk dramatically as a result of irrational human activities, triggering the "Aral Sea ecological crisis". The ecological problems of the Aral Sea have attracted widespread attention, and the alleviation of the Aral Sea ecological crisis has reached a consensus among the five Central Asian countries(Kazakhstan, Uzbekistan, Tajikistan, Kyrgyzstan, and Turkmenistan). In the past decades, many ecological management measures have been implemented for the ecological restoration of the Aral Sea. However, due to the lack of regional planning and zoning, the results are not ideal. In this study, we mapped the ecological zoning of the Aral Sea from the perspective of ecological restoration based on soil type, soil salinity, surface water, groundwater table, Normalized Difference Vegetation Index(NDVI), land cover, and aerosol optical depth(AOD) data. Soil salinization and salt dust are the most prominent ecological problems in the Aral Sea. We divided the Aral Sea into 7 first-level ecological restoration subregions(North Aral Sea catchment area in the downstream of the Syr Darya River(Subregion Ⅰ);artificial flood overflow area in the downstream of the Aral Sea(Subregion Ⅱ);physical/chemical remediation area of the salt dust source area in the eastern part of the South Aral Sea(Subregion Ⅲ);physical/chemical remediation area of severe salinization in the central part of the South Aral Sea(Subregion Ⅳ);existing water surface and potential restoration area of the South Aral Sea(Subregion Ⅴ);Aral Sea vegetation natural recovery area(Subregion Ⅵ);and vegetation planting area with slight salinization in the South Aral Sea(Subregion Ⅶ)) and 14 second-level ecological restoration subregions according to the ecological zoning principles. Implementable measures are proposed for each ecological restoration subregion. For Subregion Ⅰ and Subregion Ⅱ with lower elevations, artificial flooding should be carried out to restore the surface of the Aral Sea. Subregion Ⅲ and Subregion Ⅳ have severe salinization, making it difficult for vegetation to grow. In these subregions, it is recommended to cover and pave the areas with green biomatrix coverings and environmentally sustainable bonding materials. In Subregion Ⅴ located in the central and western parts of the South Aral Sea, surface water recharge should be increased to ensure that this subregion can maintain normal water levels. In Subregion Ⅵ and Subregion Ⅶ where natural conditions are suitable for vegetation growth, measures such as afforestation and buffer zones should be implemented to protect vegetation. This study could provide a reference basis for future comprehensive ecological management and restoration of the Aral Sea.
基金supported by the National Natural Science Foundation of China(42376221,42276083)Director Research Fund Project of Guangzhou Marine Geological Survey(2023GMGSJZJJ00030)+2 种基金National Key Research and Development Program of China(2021YFC2800901)Guangdong Major Project of Basic and Applied Basic Research(2020B030103003)the project of the China Geological Survey(DD20230064).
文摘Many locations with concentrated hydrates at vents have confirmed the presence of abundant thermogenic gas in the middle of the Qiongdongnan Basin(QDNB).However,the impact of deep structures on gasbearing fluids migration and gas hydrates distribution in tectonically inactive regions is still unclear.In this study,the authors apply high-resolution 3D seismic and logging while drilling(LWD)data from the middle of the QDNB to investigate the influence of deep-large faults on gas chimneys and preferred gasescape pipes.The findings reveal the following:(1)Two significant deep-large faults,F1 and F2,developed on the edge of the Songnan Low Uplift,control the dominant migration of thermogenic hydrocarbons and determine the initial locations of gas chimneys.(2)The formation of gas chimneys is likely related to fault activation and reactivation.Gas chimney 1 is primarily arises from convergent fluid migration resulting from the intersection of the two faults,while the gas chimney 2 benefits from a steeper fault plane and shorter migration distance of fault F2.(3)Most gas-escape pipes are situated near the apex of the two faults.Their reactivations facilitate free gas flow into the GHSZ and contribute to the formation of fracture‐filling hydrates.
基金supported by the Chinese-Norwegian Collaboration Projects within Climate Systems jointly funded by the National Key Research and Development Program of China (Grant No.2022YFE0106800)the Research Council of Norway funded project MAPARC (Grant No.328943)+2 种基金the support from the Research Council of Norway funded project BASIC (Grant No.325440)the Horizon 2020 project APPLICATE (Grant No.727862)High-performance computing and storage resources were performed on resources provided by Sigma2 - the National Infrastructure for High-Performance Computing and Data Storage in Norway (through projects NS8121K,NN8121K,NN2345K,NS2345K,NS9560K,NS9252K,and NS9034K)。
文摘To quantify the relative contributions of Arctic sea ice and unforced atmospheric internal variability to the “warm Arctic, cold East Asia”(WACE) teleconnection, this study analyses three sets of large-ensemble simulations carried out by the Norwegian Earth System Model with a coupled atmosphere–land surface model, forced by seasonal sea ice conditions from preindustrial, present-day, and future periods. Each ensemble member within the same set uses the same forcing but with small perturbations to the atmospheric initial state. Hence, the difference between the present-day(or future) ensemble mean and the preindustrial ensemble mean provides the ice-loss-induced response, while the difference of the individual members within the present-day(or future) set is the effect of atmospheric internal variability. Results indicate that both present-day and future sea ice loss can force a negative phase of the Arctic Oscillation with a WACE pattern in winter. The magnitude of ice-induced Arctic warming is over four(ten) times larger than the ice-induced East Asian cooling in the present-day(future) experiment;the latter having a magnitude that is about 30% of the observed cooling. Sea ice loss contributes about 60%(80%) to the Arctic winter warming in the present-day(future) experiment. Atmospheric internal variability can also induce a WACE pattern with comparable magnitudes between the Arctic and East Asia. Ice-lossinduced East Asian cooling can easily be masked by atmospheric internal variability effects because random atmospheric internal variability may induce a larger magnitude warming. The observed WACE pattern occurs as a result of both Arctic sea ice loss and atmospheric internal variability, with the former dominating Arctic warming and the latter dominating East Asian cooling.
基金provided by the Priority Academic Program Development of Jiangsu Higher Education Institutions of China(No.SZBF2011-6-B35)the Fundamental Research Funds for the Central Universities of China(No.2012LWB42)
文摘Considering the danger of water inrush in mining very thick coal seam under water-rich roof in Majialiang Coal Mine,the universal discrete element(UDEC)software was used to simulate the overburden fracture evolution laws when mining 4#coal seam.Besides,this study researched on the influence of face advancing length,speed and mining height on the height of the water flowing fractured zones(HWFFZ),and analyzed the correlation of face advancing length and change rules of aquifer water levels and goaf water inflow.Based on those mentioned above,this research proposed the following water-controlling technologies:draining the roof water before mining,draining goaf water,reasonable advancing speed and mining thickness.These water-controlling technologies were successfully used in the feld,thus ensured safely mining the very thick coal seam under water-rich roof.
基金The Chinese Academy of Sciences(CAS)Key Deployment Project of Centre for Ocean Mega-Research of Science under contract No.COMS2020Q07the Open Fund Project of Key Laboratory of Marine Environmental Information Technology,Ministry of Natural Resourcesthe National Natural Science Foundation of China under contract No.41901133.
文摘Arctic sea ice is broadly regarded as an indicator and amplifier of global climate change.The rapid changes in Arctic sea ice have been widely concerned.However,the spatiotemporal changes in the horizontal and vertical dimensions of Arctic sea ice and its asymmetry during the melt and freeze seasons are rarely quantified simultaneously based on multiple sources of the same long time series.In this study,the spatiotemporal variation and freeze-thaw asymmetry of Arctic sea ice were investigated from both the horizontal and vertical dimensions during 1979–2020 based on remote sensing and assimilation data.The results indicated that Arctic sea ice was declining at a remarkably high rate of–5.4×10^(4) km^(2)/a in sea ice area(SIA)and–2.2 cm/a in sea ice thickness(SIT)during 1979 to 2020,and the reduction of SIA and SIT was the largest in summer and the smallest in winter.Spatially,compared with other sub-regions,SIA showed a sharper declining trend in the Barents Sea,Kara Sea,and East Siberian Sea,while SIT presented a larger downward trend in the northern Canadian Archipelago,northern Greenland,and the East Siberian Sea.Regarding to the seasonal trend of sea ice on sub-region scale,the reduction rate of SIA exhibited an apparent spatial heterogeneity among seasons,especially in summer and winter,i.e.,the sub-regions linked to the open ocean exhibited a higher decline rate in winter;however,the other sub-regions blocked by the coastlines presented a greater decline rate in summer.For SIT,the sub-regions such as the Beaufort Sea,East Siberian Sea,Chukchi Sea,Central Arctic,and Canadian Archipelago always showed a higher downward rate in all seasons.Furthermore,a striking freeze-thaw asymmetry of Arctic sea ice was also detected.Comparing sea ice changes in different dimensions,sea ice over most regions in the Arctic showed an early retreat and rapid advance in the horizontal dimension but late melting and gradual freezing in the vertical dimension.The amount of sea ice melting and freezing was disequilibrium in the Arctic during the considered period,and the rate of sea ice melting was 0.3×10^(4) km^(2)/a and 0.01 cm/a higher than that of freezing in the horizontal and vertical dimensions,respectively.Moreover,there were notable shifts in the melting and freezing of Arctic sea ice in 1997/2003 and 2000/2004,respectively,in the horizontal/vertical dimension.