The Southern Ocean is a critical component in the Earth system by dominating the global heat and anthropogenic carbon uptake and supplying heat to melt the largest ice sheet.Variability and changes in the water masses...The Southern Ocean is a critical component in the Earth system by dominating the global heat and anthropogenic carbon uptake and supplying heat to melt the largest ice sheet.Variability and changes in the water masses of the Southern Ocean are thus important to the global energy and water cycles,carbon cycling,and sea-level change.In this article,we review the recent progress on understanding the variability and changes in the four major water masses in the Southern Ocean,including Subantarctic Mode Water,Antarctic Intermediate Water,Circumpolar Deep Water and Antarctic Bottom Water.Subantarctic Mode Water and Antarctic Intermediate Water show statistically significant strong circumpolar shoaling,warming,and density reductions since 1970s,indicating that signals of global warming have entered the interior ocean.Meanwhile,strong regional variability of Subantarctic Mode Water and Antarctic Intermediate Water responding to surface buoyancy forcing and westerly winds is attracting more attention.Circumpolar Deep Water is an important modulator of heat content and nutrient concentrations on continental shelves around Antarctica and has made significant contributions to the basal melting of Antarctic ice shelves.Since the late 1950s,a long-term freshening trend in Antarctic Bottom Water in the Ross Sea and its downstream region has been observed and is mainly attributed to the accelerated basal melting of ice shelves in West Antarctica.The shrinking of Antarctic Bottom Water in the Weddell Sea during 1992–2020 has also been revealed and is attributed to reduced sea ice production over the southern Weddell continental shelf related to the Interdecadal Pacific Oscillation and the variability in the Amundsen Sea Low.Though significant advances have been achieved,there is an urgent need to enhance and improve both observations and model performances for better understandings and projections of the formation,transformation,and transport of the water masses in the Southern Ocean.展开更多
A three-dimensional coupled sea ice-ice shelf-ocean numerical model is developed for the Prydz Bay,Antarctica,using the Regional Ocean Modeling System with a grid resolution of approximately 2 km.The influence of the ...A three-dimensional coupled sea ice-ice shelf-ocean numerical model is developed for the Prydz Bay,Antarctica,using the Regional Ocean Modeling System with a grid resolution of approximately 2 km.The influence of the grounding giant iceberg D15 on the distribution of sea ice and polynyas in the Prydz Bay is analyzed through two numerical experiments.Iceberg D15,grounded off the western edge of the West Ice Shelf(WIS),obstructs the southwestward transport of sea ice along the east coast of Prydz Bay,causing sea ice to accumulate to the east of the iceberg and form multi-year fast ice.Grounding of Iceberg D15 also decreases sea ice coverage off its south edge and creates ice-free openings in spring near Davis Station and Zhongshan Station,facilitating the accessibility of vessels to the research stations.These simulated sea ice patterns closely match current satellite observations.When Iceberg D15 is removed,the previously blocked sea ice north of the iceberg,which moved westward,shifts southwesterly along the coastline,leading to a reduction in sea ice thickness during winter and spring,as well as lower sea ice concentrations in spring across large areas north and west of the iceberg.In contrast,the sea ice thickness increases considerably southwest of the WIS,extending to the front of the Amery Ice Shelf during seasons covered by sea ice.The increase in sea ice concentration can also extend to as far as 75°E in spring.Without Iceberg D15,which previously contributed to the ice barrier of Barrier Polynya(BP),the shape of BP changes,the area of BP and Davis Polynya(DP)decreases,and the polynya off the northwest edge of the WIS near 83°E expands.These polynya patterns are much similar to the satellite remote sensing observations before Iceberg D15 was grounded.From April to October,the total area of BP and DP decreases by 2.83×10^(4)km^(2)(60%)and 2.20×10^(3)km^(2)(20%),respectively,while the total sea ice production decreases by 4.11×10^(10)m^(3)(66%)and 1.52×10^(10)m^(3)(52%)compared to the experiment with iceberg.These results indicate the substantial effects of grounding giant icebergs on the spatio-temporal distribution of sea ice,the area of polynyas,and sea ice production.High-resolution Antarctic coastal numerical models,typically with grid scales of kilometers,are sufficient to represent large icebergs,and adding the grounding giant icebergs is crucial for producing realistic simulations of sea ice and polynyas.展开更多
The Southern Ocean breeds a special ecosystem.The evolution and adaptability of Antarctic marine organisms is a key research field of the Scientific Committee on Antarctic Research.The study of the Antarctic marine ec...The Southern Ocean breeds a special ecosystem.The evolution and adaptability of Antarctic marine organisms is a key research field of the Scientific Committee on Antarctic Research.The study of the Antarctic marine ecosystem is also one of the tasks of Chinese National Antarctic Research Expedition(CHINARE).However,the early investigations by Chinese scientists mainly focused on plankton and benthos,as well as their environmental variables.Since 2019,financially supported by National Polar Special Program“Impact and Response of Antarctic Seas to Climate Change”(IRASCC),the research objects have been gradually expanded to large marine animal,such as birds and mammals,and other related disciplines.展开更多
基金The Independent Research Foundation of Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)under contract Nos SML2023SP201 and SML2021SP306the Natural Science Foundation of Guangdong Province of China under contract No.2024A1515012717+5 种基金the Initial Research Foundation of Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)under contract Nos 313021004,313022009,and 313022001the National Natural Science Foundation of China under contract No.41706225the National Key R&D Program of China under contract No.2018YFA0605701the Impact and Response of Antarctic Seas to Climate Change under contract No.IRASCC 1-02-01Bthe Shenlan Program funded by Shanghai Jiao Tong University under contract No.SL2020MS021the fund from Shanghai Frontiers Science Center of Polar Research.
文摘The Southern Ocean is a critical component in the Earth system by dominating the global heat and anthropogenic carbon uptake and supplying heat to melt the largest ice sheet.Variability and changes in the water masses of the Southern Ocean are thus important to the global energy and water cycles,carbon cycling,and sea-level change.In this article,we review the recent progress on understanding the variability and changes in the four major water masses in the Southern Ocean,including Subantarctic Mode Water,Antarctic Intermediate Water,Circumpolar Deep Water and Antarctic Bottom Water.Subantarctic Mode Water and Antarctic Intermediate Water show statistically significant strong circumpolar shoaling,warming,and density reductions since 1970s,indicating that signals of global warming have entered the interior ocean.Meanwhile,strong regional variability of Subantarctic Mode Water and Antarctic Intermediate Water responding to surface buoyancy forcing and westerly winds is attracting more attention.Circumpolar Deep Water is an important modulator of heat content and nutrient concentrations on continental shelves around Antarctica and has made significant contributions to the basal melting of Antarctic ice shelves.Since the late 1950s,a long-term freshening trend in Antarctic Bottom Water in the Ross Sea and its downstream region has been observed and is mainly attributed to the accelerated basal melting of ice shelves in West Antarctica.The shrinking of Antarctic Bottom Water in the Weddell Sea during 1992–2020 has also been revealed and is attributed to reduced sea ice production over the southern Weddell continental shelf related to the Interdecadal Pacific Oscillation and the variability in the Amundsen Sea Low.Though significant advances have been achieved,there is an urgent need to enhance and improve both observations and model performances for better understandings and projections of the formation,transformation,and transport of the water masses in the Southern Ocean.
基金The National Natural Science Foundation of China under contract Nos 41976217 and 42306249the National Key Research and Development Program of China under contract No.2018YFA0605701.
文摘A three-dimensional coupled sea ice-ice shelf-ocean numerical model is developed for the Prydz Bay,Antarctica,using the Regional Ocean Modeling System with a grid resolution of approximately 2 km.The influence of the grounding giant iceberg D15 on the distribution of sea ice and polynyas in the Prydz Bay is analyzed through two numerical experiments.Iceberg D15,grounded off the western edge of the West Ice Shelf(WIS),obstructs the southwestward transport of sea ice along the east coast of Prydz Bay,causing sea ice to accumulate to the east of the iceberg and form multi-year fast ice.Grounding of Iceberg D15 also decreases sea ice coverage off its south edge and creates ice-free openings in spring near Davis Station and Zhongshan Station,facilitating the accessibility of vessels to the research stations.These simulated sea ice patterns closely match current satellite observations.When Iceberg D15 is removed,the previously blocked sea ice north of the iceberg,which moved westward,shifts southwesterly along the coastline,leading to a reduction in sea ice thickness during winter and spring,as well as lower sea ice concentrations in spring across large areas north and west of the iceberg.In contrast,the sea ice thickness increases considerably southwest of the WIS,extending to the front of the Amery Ice Shelf during seasons covered by sea ice.The increase in sea ice concentration can also extend to as far as 75°E in spring.Without Iceberg D15,which previously contributed to the ice barrier of Barrier Polynya(BP),the shape of BP changes,the area of BP and Davis Polynya(DP)decreases,and the polynya off the northwest edge of the WIS near 83°E expands.These polynya patterns are much similar to the satellite remote sensing observations before Iceberg D15 was grounded.From April to October,the total area of BP and DP decreases by 2.83×10^(4)km^(2)(60%)and 2.20×10^(3)km^(2)(20%),respectively,while the total sea ice production decreases by 4.11×10^(10)m^(3)(66%)and 1.52×10^(10)m^(3)(52%)compared to the experiment with iceberg.These results indicate the substantial effects of grounding giant icebergs on the spatio-temporal distribution of sea ice,the area of polynyas,and sea ice production.High-resolution Antarctic coastal numerical models,typically with grid scales of kilometers,are sufficient to represent large icebergs,and adding the grounding giant icebergs is crucial for producing realistic simulations of sea ice and polynyas.
文摘The Southern Ocean breeds a special ecosystem.The evolution and adaptability of Antarctic marine organisms is a key research field of the Scientific Committee on Antarctic Research.The study of the Antarctic marine ecosystem is also one of the tasks of Chinese National Antarctic Research Expedition(CHINARE).However,the early investigations by Chinese scientists mainly focused on plankton and benthos,as well as their environmental variables.Since 2019,financially supported by National Polar Special Program“Impact and Response of Antarctic Seas to Climate Change”(IRASCC),the research objects have been gradually expanded to large marine animal,such as birds and mammals,and other related disciplines.
