Recent developments in Unmanned Aerial Vehicles(UAVs)and their applications in various subjects are of interest to polar communities.Due to the harsh climate and dangerous environment,these regions pose challenges for...Recent developments in Unmanned Aerial Vehicles(UAVs)and their applications in various subjects are of interest to polar communities.Due to the harsh climate and dangerous environment,these regions pose challenges for the expedition teams.Several countries have tested the UAV technology to support Antarctic research and logistics.In this trend paper,we provide insightful reviews and discussions on such a prospective topic.Based on a comprehensive literature survey,we firstly summarize the key research progress of UAV in Antarctic studies.Then the examples of risk scenarios during the field exploration are given,after which several promising applications of the UAVs in safety guarantee are illustrated.In particular,we present a case of site-selection for the Chinese first ice sheet airfield,using the data collected in the 34th Chinese National Antarctic Research Expedition(CHINARE).In the end,we highlight the unique value of the UAVs in the popularization of polar science before concluding the advantages and limitations.Considering their excellent performance,we expect more innovations for UAV’s applications in the following Antarctic expeditions.展开更多
The Amery Ice Shelf is the largest ice shelf in East Antarctica. It drains continental ice from an area of more than one million square kilometres through a section of coastline that represents approximately 2% of the...The Amery Ice Shelf is the largest ice shelf in East Antarctica. It drains continental ice from an area of more than one million square kilometres through a section of coastline that represents approximately 2% of the total circumference of the Antarctic continent. In this study, we used a time series of ENVISAT ASAR images from 2004-2012 and flow lines derived from surface velocity data to monitor the changes in 12 tributaries of the Amery Ice Shelf front. The results show that the Amery Ice Shelf has been expanding and that the rates of expansion differ across the shelf. The highest average annual rate of advance from 2004-2012 was 3.36 m＇d-1 and the lowest rate was 1.65 m.d-1. The rates in 2009 and 2010 were generally lower than those in other years. There was a low correlation between the rate of expansion and the atmospheric temperature recorded at a nearby research station, however the mechanism of the relationship was complex. This study shows that the expansion of the Amery Ice Shelf is slowing down, reflecting a changing trend in climate and ice conditions in East Antarctica.展开更多
On 10 December 2017,a Chinese research vessel R/V Xuelong encountered an extensive area of landfast ice offshore Inexpressible Island(Antarctica)near the location where the fifth Chinese Antarctic research station is ...On 10 December 2017,a Chinese research vessel R/V Xuelong encountered an extensive area of landfast ice offshore Inexpressible Island(Antarctica)near the location where the fifth Chinese Antarctic research station is to be built.Using multi-source satellite images and weather data,we analyzed the ice conditions during the event season and reconstructed the development of landfast ice.Two stages in late September and early October were identified as contributing to the final ice extent.These two events are highly related to local-and large-scale weather conditions.Satellite images from 2003 to 2017 showed that four in fifteen years experienced severe landfast ice conditions,suggesting that it is not a rare phenomenon.展开更多
The business of the Arctic has received increased attention owing to climate change.However,resource development and the use of waterways threaten the fragile Arctic ecology.The indigenous people of the Arctic have ac...The business of the Arctic has received increased attention owing to climate change.However,resource development and the use of waterways threaten the fragile Arctic ecology.The indigenous people of the Arctic have acquired a vast amount of traditional knowledge about coexisting in harmony with nature over the course of many years.Herein,five types of fish storage facilities that are commonly used by Arctic indigenous people and their working mechanisms are described.The traditional knowledge of the Arctic indigenous people is practically applied in Arctic fish storage systems,which are still common,effective,and environmentally friendly.The traditional fish storage facilities of the aborigines are of significance because they promote the sustainable development of the Arctic.展开更多
The North Water Polynya(NOW)is one of the largest and most productive polynyas in the Arctic.Compared to the surrounding sea ice,the combination of high winds and cold air,together with the thin ice or open water surf...The North Water Polynya(NOW)is one of the largest and most productive polynyas in the Arctic.Compared to the surrounding sea ice,the combination of high winds and cold air,together with the thin ice or open water surface of the NOW,produces large turbulent heat fluxes(THFs).The accurate estimation of these parameters requires high-resolution atmospheric data,which can be provided by the reanalysis products from different sources.In this study,we calculated the winter latent heat flux(LHF)and sensible heat flux(SHF)over the NOW and its surrounding sea ice area from 2005/2006 to 2015/2016 using high-resolution(15 km)Arctic System Reanalysis version 2(ASRv2)data and low-resolution(30 km)European Centre for Medium-Range Weather Forecasts ERA5 data.Results show that the LHF/SHF over the surrounding sea ice is about 82%/88%lower than over the NOW,as estimated using either dataset.Furthermore,within each area,the difference in the THFs estimated from the two datasets is small.The spatial distribution of the LHF/SHF estimated from both data sources is similar to that of sea ice concentration.The average LHF/SHF in the polynya obtained using ASRv2 data is only 5%/7%higher than that from the values obtained using ERA5 data.This is because the wind speed and air temperature from the ASRv2 data are higher than those of ERA5,and their effects on the THFs can cancel each other out.Furthermore,the estimated THFs do not necessarily improve with the refined resolution of ASRv2.展开更多
A revised Landsat Image Mosaic of Antarctica （LIMA） is presented, using the 1073 multi-band scenes of the original Land- sat-7 ETM＋ LIMA image collection available at the United States Geological Survey （USGS： h...A revised Landsat Image Mosaic of Antarctica （LIMA） is presented, using the 1073 multi-band scenes of the original Land- sat-7 ETM＋ LIMA image collection available at the United States Geological Survey （USGS： http：//lima.usgs.gov/）. Three improvements have been applied during the data processing： （1） DN saturation is adjusted by adopting a linear regression, which has a lower root mean square error than the ratio regression used by LIMA; （2） solar elevation angle is calculated using pixel-level latitude/longitude and the acquisition time and date of the central pixel of the scene, improving slightly upon the bi- linear interpolation of the solar elevation angles of scene comers applied in LIMA; and （3） two additional image bands, Band 5 and Band 7, are sharpened using the panchromatic band （Band 8） and a Gram-Schmidt Spectral Sharpening algorithm to more easily distinguish snow, cloud and exposed rocks. The final planetary reflectance product is stored in 16-bit bands to preserve the full radiometric content of the scenes. A comparative statistical analysis among 12 sample regions indicates that the new mosaic has enhanced visual qualities, information entropy, and information content for land cover classification relative to LIMA.展开更多
Ice shelf breakups account for most mass loss from the Antarctic Ice Sheet as the consequence of the propagation of crevasses(or rift)in response to stress.Thus there is a pressing need for detecting crevasses’locati...Ice shelf breakups account for most mass loss from the Antarctic Ice Sheet as the consequence of the propagation of crevasses(or rift)in response to stress.Thus there is a pressing need for detecting crevasses’location and depth,to understand the mechanism of calving processes.This paper presents a method of crevasse detection using the ICESat-1/GLAS data.A case study was taken at the Amery Ice Shelf of Antarctica to verify the accuracy of geo-location and depth of crevasses detected.Moreover,based on the limited crevasse points,we developed a method to detect the peak stress points which can be used to track the location of the crack tips and to identify the possible high-risk area where an ice shelf begins to break up.The spatial and temporal distribution of crevasse depth and the spatial distribution of peak stress points of the Amery Ice Shelf were analyzed through 132 tracks in 16 campaign periods of ICESat-1/GLAS between 2003 and 2008.The results showed that the depth of the detected crevasse points ranged from 2 to 31.7 m,which were above the sea level;the crevasse that advected downstream to the front edge of an ice shelf has little possibility to directly result in breakups because the crevasse depth did not show any increasing trend over time;the local stress concentration is distributed mainly in the suture zones on the ice shelves.展开更多
Antarctica plays a key role in global energy balance and sea level change.It has been conventionally viewed as a whole ice body with high albedo in General Circulation Models or Regional Climate Models and the differe...Antarctica plays a key role in global energy balance and sea level change.It has been conventionally viewed as a whole ice body with high albedo in General Circulation Models or Regional Climate Models and the differences of land cover has usually been overlooked.Land cover in Antarctica is one of the most important drivers of changes in the Earth system.Detailed land cover information over the Antarctic region is necessary as spatial resolution improves in land process models.However,there is a lack of complete Antarctic land cover dataset derived from a consistent data source.To fill this data gap,we have produced a database named Antarctic Land Cover Database for the Year 2000(AntarcticaLC2000) using Landsat Enhanced Thematic Mapper Plus(ETM+) data acquired around 2000 and Moderate Resolution Imaging Spectrometer(MODIS) images acquired in the austral summer of 2003/2004 according to the criteria for the 1:100000-scale.Three land cover types were included in this map,separately,ice-free rocks,blue ice,and snow/firn.This classification legend was determined based on a review of the land cover systems in Antarctica(LCCSA) and an analysis of different land surface types and the potential of satellite data.Image classification was conducted through a combined usage of computer-aided and manual interpretation methods.A total of 4067 validation sample units were collected through visual interpretation in a stratified random sampling manner.An overall accuracy of 92.3%and the Kappa coefficient of 0.836 were achieved.Results show that the areas and percentages of ice-free rocks,blue ice,and snow/firn are 73268.81 km2(0.537%),225937.26 km2(1.656%),and 13345460.41 km2(97.807%),respectively.The comparisons with other different data proved a higher accuracy of our product and a more advantageous data quality.These indicate that AntarcticaLC2000,the new land cover dataset for Antarctica entirely derived from satellite data,is a reliable product for a broad spectrum of applications.展开更多
Antarctic tabular icebergs are important active components in the ice sheet-ice shelf-ocean system.Seafloor topography is the key factor that affects the drifting and grounding of icebergs,but it has not been fully in...Antarctic tabular icebergs are important active components in the ice sheet-ice shelf-ocean system.Seafloor topography is the key factor that affects the drifting and grounding of icebergs,but it has not been fully investigated.This study analyzes the impact of seafloor topography on the drifting and grounding of Antarctic tabular icebergs using Bedmap-2 datasets and iceberg route tracking data from Brigham Young University.The results highlight the following points.(1) The quantitative distributions of iceberg grounding events and the tracking points of grounded icebergs are mainly affected by iceberg draft and reach their peak values in sea water with depths between 200 m and 300 m.The peak tracking point number and linear velocity of free-drifting icebergs are found in the Antarctic Slope Front(water depth of approximately 500 m).(2) The area of possible grounding regions of small-scale icebergs calved from ice shelf fronts accounts for 28%of the sea area at water depths less than 2000 m outside the Antarctic coastline periphery(3.62 million km2).Their spatial distribution is mainly around East Antarctica and the Antarctic Peninsula.The area of possible grounding regions of large tabular icebergs with long axes larger than 18.5 km(in water depths of less than 800 m) accounts for 74%of the sea area.(3) The iceberg drifting velocity is positively correlated with ocean depth in areas where the depth is less than 2000 m(R=0.85,P<0.01).This result confirms the effect of water depth variations induced by seafloor topography fluctuations on iceberg drifting velocity.展开更多
基金Supported by the Chinese Arctic and Antarctic Administration,the National Key R&D Program of China(2017YFA0604401)National Basic Research Program of China(2012CB957704)+2 种基金Fundamental Research Funds for the Central Universities(312231103)Discipline construction funds(31223110)Open Fund of State Key Laboratory of Remote Sensing Science(OFSLRSS201609)
基金the National Natural Science Foundation of China(Grant nos.41830536,41676176 and 41676182)the Chinese Polar Environment Comprehensive Investigation and Assessment ProgramTeng Li is also funded by the UK-China Joint Research and Innovation Partnership Fund PhD Placement Program.
文摘Recent developments in Unmanned Aerial Vehicles(UAVs)and their applications in various subjects are of interest to polar communities.Due to the harsh climate and dangerous environment,these regions pose challenges for the expedition teams.Several countries have tested the UAV technology to support Antarctic research and logistics.In this trend paper,we provide insightful reviews and discussions on such a prospective topic.Based on a comprehensive literature survey,we firstly summarize the key research progress of UAV in Antarctic studies.Then the examples of risk scenarios during the field exploration are given,after which several promising applications of the UAVs in safety guarantee are illustrated.In particular,we present a case of site-selection for the Chinese first ice sheet airfield,using the data collected in the 34th Chinese National Antarctic Research Expedition(CHINARE).In the end,we highlight the unique value of the UAVs in the popularization of polar science before concluding the advantages and limitations.Considering their excellent performance,we expect more innovations for UAV’s applications in the following Antarctic expeditions.
基金supported by the Specialized Research Fund for the Doctoral Program of Higher Education (Grant no.20120003110030)the China Postdoctoral Science Foundation (Grant no.201104063)+1 种基金the Open Fund of the SOA Key Laboratory for Polar Science (Grant no.KP201101)the Fundamental Research Funds for the Central Universities (Grant no.105560GR)
文摘The Amery Ice Shelf is the largest ice shelf in East Antarctica. It drains continental ice from an area of more than one million square kilometres through a section of coastline that represents approximately 2% of the total circumference of the Antarctic continent. In this study, we used a time series of ENVISAT ASAR images from 2004-2012 and flow lines derived from surface velocity data to monitor the changes in 12 tributaries of the Amery Ice Shelf front. The results show that the Amery Ice Shelf has been expanding and that the rates of expansion differ across the shelf. The highest average annual rate of advance from 2004-2012 was 3.36 m＇d-1 and the lowest rate was 1.65 m.d-1. The rates in 2009 and 2010 were generally lower than those in other years. There was a low correlation between the rate of expansion and the atmospheric temperature recorded at a nearby research station, however the mechanism of the relationship was complex. This study shows that the expansion of the Amery Ice Shelf is slowing down, reflecting a changing trend in climate and ice conditions in East Antarctica.
基金supported by the National Natural Science Foundation of China (Grant nos. 41676176 and 41830536)the Open Fund of State Key Laboratory of Remote Sensing Science (Grant no. OFSLRSS201926)
文摘On 10 December 2017,a Chinese research vessel R/V Xuelong encountered an extensive area of landfast ice offshore Inexpressible Island(Antarctica)near the location where the fifth Chinese Antarctic research station is to be built.Using multi-source satellite images and weather data,we analyzed the ice conditions during the event season and reconstructed the development of landfast ice.Two stages in late September and early October were identified as contributing to the final ice extent.These two events are highly related to local-and large-scale weather conditions.Satellite images from 2003 to 2017 showed that four in fifteen years experienced severe landfast ice conditions,suggesting that it is not a rare phenomenon.
基金the Impact of Polar Environment Changes to our Country’s Polar Security(Grant no.2019YFC1408203)。
文摘The business of the Arctic has received increased attention owing to climate change.However,resource development and the use of waterways threaten the fragile Arctic ecology.The indigenous people of the Arctic have acquired a vast amount of traditional knowledge about coexisting in harmony with nature over the course of many years.Herein,five types of fish storage facilities that are commonly used by Arctic indigenous people and their working mechanisms are described.The traditional knowledge of the Arctic indigenous people is practically applied in Arctic fish storage systems,which are still common,effective,and environmentally friendly.The traditional fish storage facilities of the aborigines are of significance because they promote the sustainable development of the Arctic.
基金supported by the National Key Research and Development Program of China(Grant no.2024YFB3908004).
文摘The North Water Polynya(NOW)is one of the largest and most productive polynyas in the Arctic.Compared to the surrounding sea ice,the combination of high winds and cold air,together with the thin ice or open water surface of the NOW,produces large turbulent heat fluxes(THFs).The accurate estimation of these parameters requires high-resolution atmospheric data,which can be provided by the reanalysis products from different sources.In this study,we calculated the winter latent heat flux(LHF)and sensible heat flux(SHF)over the NOW and its surrounding sea ice area from 2005/2006 to 2015/2016 using high-resolution(15 km)Arctic System Reanalysis version 2(ASRv2)data and low-resolution(30 km)European Centre for Medium-Range Weather Forecasts ERA5 data.Results show that the LHF/SHF over the surrounding sea ice is about 82%/88%lower than over the NOW,as estimated using either dataset.Furthermore,within each area,the difference in the THFs estimated from the two datasets is small.The spatial distribution of the LHF/SHF estimated from both data sources is similar to that of sea ice concentration.The average LHF/SHF in the polynya obtained using ASRv2 data is only 5%/7%higher than that from the values obtained using ERA5 data.This is because the wind speed and air temperature from the ASRv2 data are higher than those of ERA5,and their effects on the THFs can cancel each other out.Furthermore,the estimated THFs do not necessarily improve with the refined resolution of ASRv2.
文摘海洋动物是南极气候变化的"生物指示剂",其排泄物中丰富的碳(C)和氮(N)等营养物质为土壤中温室气体的产生与排放提供了有利条件,企鹅作为一种重要的海洋动物,因此其聚居区成为甲烷(CH4)和氧化亚氮(N2O)等温室气体排放的潜在"热点"区域.然而,受企鹅数量遥感资料的限制,区域尺度上企鹅源温室气体排放总量尚缺乏精确估算.以南极维多利亚地难言岛企鹅聚集区为研究对象,基于0.1 m分辨率航拍照片发展了面向像元的RGB颜色模型法(pixel-oriented RGB color model)识别企鹅数量,通过企鹅粪便CH4和N2O排放通量、企鹅排便量等数据建立了企鹅源温室气体估算模型.结果显示,航拍照片中企鹅像元在RGB彩色空间模型中的R值(17~104)与其他背景像元(〉110)存在显著差异,该差异可以作为将企鹅与背景像元有效分离的理论依据;南极维多利亚地难言岛企鹅总数为19150只,企鹅源CH4和N2O排放总量分别约为275和2.99 kg.
基金supported by Chinese Arctic and Antarctic Administration,National Basic Research Program of China (Grant No. 2012CB957704)National High-tech R&D Program of China (Grant Nos. 2008AA121702and 2008AA09Z117)+1 种基金National Natural Science Foundation of China(Grant Nos. 41106157 and 41176163)Open Fund of State Key Laboratory of Remote Sensing Science (Grant No. OFSLRSS201005)
文摘A revised Landsat Image Mosaic of Antarctica （LIMA） is presented, using the 1073 multi-band scenes of the original Land- sat-7 ETM＋ LIMA image collection available at the United States Geological Survey （USGS： http：//lima.usgs.gov/）. Three improvements have been applied during the data processing： （1） DN saturation is adjusted by adopting a linear regression, which has a lower root mean square error than the ratio regression used by LIMA; （2） solar elevation angle is calculated using pixel-level latitude/longitude and the acquisition time and date of the central pixel of the scene, improving slightly upon the bi- linear interpolation of the solar elevation angles of scene comers applied in LIMA; and （3） two additional image bands, Band 5 and Band 7, are sharpened using the panchromatic band （Band 8） and a Gram-Schmidt Spectral Sharpening algorithm to more easily distinguish snow, cloud and exposed rocks. The final planetary reflectance product is stored in 16-bit bands to preserve the full radiometric content of the scenes. A comparative statistical analysis among 12 sample regions indicates that the new mosaic has enhanced visual qualities, information entropy, and information content for land cover classification relative to LIMA.
基金supported by the Chinese Arctic and Antarctic Administration,Fundamental Research Funds for the Central Universities(Grant No.105560GK)National Basic Research Program of China(Grant No.2012CB957704)+1 种基金National High-tech R&D Program of China(Grant Nos.2008AA121702 and 2008AA09Z117)National Natural Science Foundation of China(Grant Nos.41176163 and 41106157)
文摘Ice shelf breakups account for most mass loss from the Antarctic Ice Sheet as the consequence of the propagation of crevasses(or rift)in response to stress.Thus there is a pressing need for detecting crevasses’location and depth,to understand the mechanism of calving processes.This paper presents a method of crevasse detection using the ICESat-1/GLAS data.A case study was taken at the Amery Ice Shelf of Antarctica to verify the accuracy of geo-location and depth of crevasses detected.Moreover,based on the limited crevasse points,we developed a method to detect the peak stress points which can be used to track the location of the crack tips and to identify the possible high-risk area where an ice shelf begins to break up.The spatial and temporal distribution of crevasse depth and the spatial distribution of peak stress points of the Amery Ice Shelf were analyzed through 132 tracks in 16 campaign periods of ICESat-1/GLAS between 2003 and 2008.The results showed that the depth of the detected crevasse points ranged from 2 to 31.7 m,which were above the sea level;the crevasse that advected downstream to the front edge of an ice shelf has little possibility to directly result in breakups because the crevasse depth did not show any increasing trend over time;the local stress concentration is distributed mainly in the suture zones on the ice shelves.
基金supported by the Chinese Arctic and Antarctic Administration.National Basic Research Program of China(Grant No.2012CB957704)National Natural Science Foundation of China(Grant Nos.41676176 & 41676182)National High-tech R&D Program of China(Grant No.2008AA09Z117)
文摘Antarctica plays a key role in global energy balance and sea level change.It has been conventionally viewed as a whole ice body with high albedo in General Circulation Models or Regional Climate Models and the differences of land cover has usually been overlooked.Land cover in Antarctica is one of the most important drivers of changes in the Earth system.Detailed land cover information over the Antarctic region is necessary as spatial resolution improves in land process models.However,there is a lack of complete Antarctic land cover dataset derived from a consistent data source.To fill this data gap,we have produced a database named Antarctic Land Cover Database for the Year 2000(AntarcticaLC2000) using Landsat Enhanced Thematic Mapper Plus(ETM+) data acquired around 2000 and Moderate Resolution Imaging Spectrometer(MODIS) images acquired in the austral summer of 2003/2004 according to the criteria for the 1:100000-scale.Three land cover types were included in this map,separately,ice-free rocks,blue ice,and snow/firn.This classification legend was determined based on a review of the land cover systems in Antarctica(LCCSA) and an analysis of different land surface types and the potential of satellite data.Image classification was conducted through a combined usage of computer-aided and manual interpretation methods.A total of 4067 validation sample units were collected through visual interpretation in a stratified random sampling manner.An overall accuracy of 92.3%and the Kappa coefficient of 0.836 were achieved.Results show that the areas and percentages of ice-free rocks,blue ice,and snow/firn are 73268.81 km2(0.537%),225937.26 km2(1.656%),and 13345460.41 km2(97.807%),respectively.The comparisons with other different data proved a higher accuracy of our product and a more advantageous data quality.These indicate that AntarcticaLC2000,the new land cover dataset for Antarctica entirely derived from satellite data,is a reliable product for a broad spectrum of applications.
基金supported by the National Key Research and Development Program of China(Grant No. 2016YFA0600103)the National Natural Science Foundation of China (Grant Nos.41406211,41476161,41676182 & 41676176)+3 种基金the National Basic Research Program of China(Grant No.2012CB957704)the KeyLaboratory Research Fund of the National Administration of Surveying, Mapping and Geoinformation of China(Grant No.201416)the Specialized Research Fund for the Doctoral Program of Higher Education(Grant No.20120003110030)the Project of International Cooperation and Exchanges CHINARE(Grant No.201611)
文摘Antarctic tabular icebergs are important active components in the ice sheet-ice shelf-ocean system.Seafloor topography is the key factor that affects the drifting and grounding of icebergs,but it has not been fully investigated.This study analyzes the impact of seafloor topography on the drifting and grounding of Antarctic tabular icebergs using Bedmap-2 datasets and iceberg route tracking data from Brigham Young University.The results highlight the following points.(1) The quantitative distributions of iceberg grounding events and the tracking points of grounded icebergs are mainly affected by iceberg draft and reach their peak values in sea water with depths between 200 m and 300 m.The peak tracking point number and linear velocity of free-drifting icebergs are found in the Antarctic Slope Front(water depth of approximately 500 m).(2) The area of possible grounding regions of small-scale icebergs calved from ice shelf fronts accounts for 28%of the sea area at water depths less than 2000 m outside the Antarctic coastline periphery(3.62 million km2).Their spatial distribution is mainly around East Antarctica and the Antarctic Peninsula.The area of possible grounding regions of large tabular icebergs with long axes larger than 18.5 km(in water depths of less than 800 m) accounts for 74%of the sea area.(3) The iceberg drifting velocity is positively correlated with ocean depth in areas where the depth is less than 2000 m(R=0.85,P<0.01).This result confirms the effect of water depth variations induced by seafloor topography fluctuations on iceberg drifting velocity.
