The heat content(HC)of water masses on the Ross Sea continental shelf plays an important role in regulating the circulations and the basal melting of the Ross Ice Shelf(RIS).Yet,the evolution of the HC on the Ross Sea...The heat content(HC)of water masses on the Ross Sea continental shelf plays an important role in regulating the circulations and the basal melting of the Ross Ice Shelf(RIS).Yet,the evolution of the HC on the Ross Sea continental shelf is still not clear due to the sparsity of observations.By employing a coupled regional ocean-sea ice-ice shelf model for the Ross Sea,this study analyzes the heat budget of water masses over the continental shelf and in the RIS cavity.According to the topographic features and the HC density,the continental shelf region is divided into 17 subdomains.The heat budget of the middle layer for every subdomain is analyzed.In addition,the heat budget for the RIS cavity is assessed for the first time.Owing to Modified Circumpolar Deep Water intrusion,water masses over the eastern shelf are warmer than over the western shelf,with the coldest water identified in the southwestern inner shelf.The horizontal heat flux mainly provides heat to the continental shelf,while the atmospheric forcing tends to warm up the ocean during the ice-melting period and cool down the ocean during the ice-freezing period.The vertical heat flux is generally upward and transports heat from the deep layer to the upper layer.In the RIS cavity,the seasonal cycle of the HC is dominated by the horizontal flux across the RIS front rather than the basal thermal forcing of the RIS.展开更多
The oceanic general circulations in the Ross Sea,where the southernmost ocean is located,play an important role in the climate system.Yet,the energy cycle of oceanic circulations in the Ross Sea is still unclear.By em...The oceanic general circulations in the Ross Sea,where the southernmost ocean is located,play an important role in the climate system.Yet,the energy cycle of oceanic circulations in the Ross Sea is still unclear.By employing an eddypermitting coupled regional ocean-sea ice-ice shelf model,this study investigates the oceanic energy cycle in the Ross Sea.Based on the Lorenz Energy Cycle framework,the spatiotemporal distributions of kinetic energy and available potential energy within the Ross Sea are quantitatively analyzed.The power pathways and magnitudes of energy conversion are also quantified.The simulated results show that the Mean Available Potential Energy(MAPE)is the largest energy reservoir of about 527.62 PJ(1 PJ=10^(15) J),followed by the Eddy Available Potential Energy(EAPE),the Mean Kinetic Energy(MKE),and the Eddy Kinetic Energy(EKE)of about 19.20 PJ,1.04 PJ,and 0.82 PJ,respectively.In the sub-ice-shelf cavity,the maximal MAPE is up to about 177.81 PJ,and the EAPE,MKE,and EKE are about 2.58 PJ,39.87 TJ(1 TJ=10^(12) J),and 23.05 TJ,respectively.The inputs to the regional energy reservoirs are mainly from the sea surface momentum and buoyancy fluxes.The baroclinic pathway plays a dominant role in the conversion of energy to EKE,both in the open ocean and in the sub-ice-shelf cavity.The energy conversion from EAPE to EKE in the open ocean and the sub-ice-shelf cavity is about 2.86 GW(1 GW=10^(9) J)and 162.18 MW(1 MW=10^(6) J),respectively.In addition,the kinetic energy is directed from EKE to MKE in the Ross Sea,and such an energy flow in the barotropic pathway is opposite from that in the Southern Ocean.展开更多
Seasonal variation in phytoplankton composition influences the pathways and efficiency of energy flow,reshaping the structure of the trophic pyramid in the Ross Sea.However,field investigation of grazing processes pre...Seasonal variation in phytoplankton composition influences the pathways and efficiency of energy flow,reshaping the structure of the trophic pyramid in the Ross Sea.However,field investigation of grazing processes presents challenges that hinder our understanding of energy pathways.This study aims to provide insights into energy flow using a three-dimensional ecosystem model applied to the Ross Sea.By analyzing the simulation results,the role of the seasonal phytoplankton succession,specifically the shift from dominance by Phaeocystis antarctica to diatoms,in energy allocation is explored.The short-lived spring bloom of P.antarctica mainly fuels microzooplankton,creating a brief food chain where energy transfers primarily among smaller plankton.In contrast,the subsequent summer bloom of diatoms,which persists longer,provides nearly half of the total phytoplankton energy loss(via ingestion and mortality)to larger mesozooplankton.Our findings indicate that phytoplankton succession in the Ross Sea extends the bloom duration,particularly for diatoms,thereby facilitating energy transfer to higher trophic levels and improving overall energy utilization.This suggests that phytoplankton succession,an ecological strategy adapted to iron-deficient environments in the Ross Sea,explains why the colder region in front of the Ross Ice Shelf is significantly more productive than the northern areas,ultimately favored by top predators.展开更多
Research on changes in the redox conditions of bottom waters is essential for understanding deep water circulation,global ocean currents,climate change,and ecosystem health.Through sedimentary geological methods,a dee...Research on changes in the redox conditions of bottom waters is essential for understanding deep water circulation,global ocean currents,climate change,and ecosystem health.Through sedimentary geological methods,a deeper understanding of the complex relationships between various environmental changes can be achieved,providing detailed evidence and theoretical support for global climate change research.The Ross Sea in Antarctica plays a key role in the formation of Antarctic bottom water(AABW),and the complex climate changes since the last glacial maximum(LGM)make it particularly significant for study.This research analyzes core ANT32-RB16C from the Ross Sea using geochemical proxies such as major and trace elements,grain size,and redox-sensitive indicators like Mn/Ti,Co/Ti,Mo/Ti,Cd/Ti,U/Th,and Ni/Co molar concentration ratios.Combining this data with a previously established chronological framework,the study explores the evolution of redox conditions in the Ross Sea’s deep waters since the LGM.The results show that the deep waters have remained oxygen-rich since the LGM,with significant changes in four stages.Stage 1(24.7–15.7 cal ka BP):Strong oxidizing conditions,likely due to enhanced formation of Ross Sea bottom water(RSBW),increasing oxygen levels.Stage 2(15.7–4.5 cal ka BP):Weakened oxidizing conditions as temperatures rose and ice shelves retreated,increasing primary productivity and depleting oxygen.Stage 3(4.5–1.5 cal ka BP):Continued decline in oxidizing conditions,possibly linked to high primary productivity and oxygen consumption.Stage 4(1.5 cal ka BP to present):A rapid recovery of oxidizing conditions,likely driven by temperature drops,increased RSBW formation,and decreased productivity.展开更多
Antarctic coastal polynyas play a vital role in atmosphere-ocean interactions and local ecosystems.This study investigates the interannual variability of springtime coastal polynyas over the Ross Sea based on satellit...Antarctic coastal polynyas play a vital role in atmosphere-ocean interactions and local ecosystems.This study investigates the interannual variability of springtime coastal polynyas over the Ross Sea based on satellite-retrieved sea-ice concentration(SIC)data from 1992 to 2021.Firstly,the springtime coastal polynya areas display large interannual variability as well as a positive trend of about 2000 km^(2)(10 yr)^(-1) over the 30 years.Secondly,based on composite analysis,in spring,we find that a deepened Amundsen Sea Low(ASL)induces stronger meridional winds over the eastern Ross Sea,leading to stronger sea-ice advection and expansion of coastal polynya areas.This is accompanied by more solar radiation absorption in early summer(about 16 W m^(2)),resulting in upper-ocean warming(~0.4℃)and significant sea-ice loss in late summer(~50%SIC).Additionally,the physical processes are validated by 500-year piControl simulations of a state-of-the-art Earth system model.Based on the same composite analysis,the results show that the sea-ice decline is consistent with the deepening of the ASL and the increase of the meridional sea-ice advection of the preceding spring,which is highly consistent with that of observations.This further confirms the circulations-polynyas-sea-ice physical linkages.Since the springtime ASL is strongly modulated by the tropical Pacific variability and the stratospheric polar vortex,changes in the polynya areas of the Ross Sea can be traced back to remote regions.展开更多
During the 36th Chinese National Antarctic Research Expedition,aerosol samples were gathered from the Ross Sea in Antarctic to assess the climatic impact of the Australian fires that occurred in 2019-2020.The chemical...During the 36th Chinese National Antarctic Research Expedition,aerosol samples were gathered from the Ross Sea in Antarctic to assess the climatic impact of the Australian fires that occurred in 2019-2020.The chemical compositions,including levoglucosan(Lev)and its isomers,galactosan(Gan)and mannosan(Man),were analyzed.Principal component analysis helped identify the potential sources of these chemical components.By combining backward trajectories with the ratios of CLev/CMan and CMan/CGan,it was further inferred that Australia might be the potential source region for biomass burning.The radiative forcing resulting from biomass burning was evaluated using the Santa Barbara DISORT Atmospheric Radiative Transfer(SBDART)model,which revealed that black carbon emitted from biomass burning could slightly warm the atmosphere(+0.52 W·m^(-2))while causing slightly cooling at the surface(-0.73 W·m^(-2))and the top of the atmosphere(-0.22 W·m^(-2))over the Ross Sea.展开更多
基金supported by the National Key R&D Program of China (Grant No. 2024YFF0506603)the Independent Research Foundation of the Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) (Grant Nos. SML2023SP201 and SML2021SP306)+2 种基金the Natural Science Foundation of Guangdong Province, China (Grant No. 2024A1515012717)the Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) (Grant Nos. 313021004, 313022009 and 313022001)the Program of Innovation 2030 on Smart Ocean, Zhejiang University
文摘The heat content(HC)of water masses on the Ross Sea continental shelf plays an important role in regulating the circulations and the basal melting of the Ross Ice Shelf(RIS).Yet,the evolution of the HC on the Ross Sea continental shelf is still not clear due to the sparsity of observations.By employing a coupled regional ocean-sea ice-ice shelf model for the Ross Sea,this study analyzes the heat budget of water masses over the continental shelf and in the RIS cavity.According to the topographic features and the HC density,the continental shelf region is divided into 17 subdomains.The heat budget of the middle layer for every subdomain is analyzed.In addition,the heat budget for the RIS cavity is assessed for the first time.Owing to Modified Circumpolar Deep Water intrusion,water masses over the eastern shelf are warmer than over the western shelf,with the coldest water identified in the southwestern inner shelf.The horizontal heat flux mainly provides heat to the continental shelf,while the atmospheric forcing tends to warm up the ocean during the ice-melting period and cool down the ocean during the ice-freezing period.The vertical heat flux is generally upward and transports heat from the deep layer to the upper layer.In the RIS cavity,the seasonal cycle of the HC is dominated by the horizontal flux across the RIS front rather than the basal thermal forcing of the RIS.
基金The Independent Research Foundation of Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)under contract No.SML2023SP201the Natural Science Foundation of Guangdong Province,China under contract No.2024A1515012717+3 种基金the Funds of Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)under contract Nos 313021004 and 313022009the National Natural Science Foundation of China under contract No.41806216the Natural Science Foundation of Jiangsu Province under contract No.BK20211015the Program of Innovation 2030 on Smart Ocean,Zhejiang University.
文摘The oceanic general circulations in the Ross Sea,where the southernmost ocean is located,play an important role in the climate system.Yet,the energy cycle of oceanic circulations in the Ross Sea is still unclear.By employing an eddypermitting coupled regional ocean-sea ice-ice shelf model,this study investigates the oceanic energy cycle in the Ross Sea.Based on the Lorenz Energy Cycle framework,the spatiotemporal distributions of kinetic energy and available potential energy within the Ross Sea are quantitatively analyzed.The power pathways and magnitudes of energy conversion are also quantified.The simulated results show that the Mean Available Potential Energy(MAPE)is the largest energy reservoir of about 527.62 PJ(1 PJ=10^(15) J),followed by the Eddy Available Potential Energy(EAPE),the Mean Kinetic Energy(MKE),and the Eddy Kinetic Energy(EKE)of about 19.20 PJ,1.04 PJ,and 0.82 PJ,respectively.In the sub-ice-shelf cavity,the maximal MAPE is up to about 177.81 PJ,and the EAPE,MKE,and EKE are about 2.58 PJ,39.87 TJ(1 TJ=10^(12) J),and 23.05 TJ,respectively.The inputs to the regional energy reservoirs are mainly from the sea surface momentum and buoyancy fluxes.The baroclinic pathway plays a dominant role in the conversion of energy to EKE,both in the open ocean and in the sub-ice-shelf cavity.The energy conversion from EAPE to EKE in the open ocean and the sub-ice-shelf cavity is about 2.86 GW(1 GW=10^(9) J)and 162.18 MW(1 MW=10^(6) J),respectively.In addition,the kinetic energy is directed from EKE to MKE in the Ross Sea,and such an energy flow in the barotropic pathway is opposite from that in the Southern Ocean.
基金The National Natural Science Foundation of China under contract No.41941008the National Key Research and Development Program of China under contract No.2023YFC3107702.
文摘Seasonal variation in phytoplankton composition influences the pathways and efficiency of energy flow,reshaping the structure of the trophic pyramid in the Ross Sea.However,field investigation of grazing processes presents challenges that hinder our understanding of energy pathways.This study aims to provide insights into energy flow using a three-dimensional ecosystem model applied to the Ross Sea.By analyzing the simulation results,the role of the seasonal phytoplankton succession,specifically the shift from dominance by Phaeocystis antarctica to diatoms,in energy allocation is explored.The short-lived spring bloom of P.antarctica mainly fuels microzooplankton,creating a brief food chain where energy transfers primarily among smaller plankton.In contrast,the subsequent summer bloom of diatoms,which persists longer,provides nearly half of the total phytoplankton energy loss(via ingestion and mortality)to larger mesozooplankton.Our findings indicate that phytoplankton succession in the Ross Sea extends the bloom duration,particularly for diatoms,thereby facilitating energy transfer to higher trophic levels and improving overall energy utilization.This suggests that phytoplankton succession,an ecological strategy adapted to iron-deficient environments in the Ross Sea,explains why the colder region in front of the Ross Ice Shelf is significantly more productive than the northern areas,ultimately favored by top predators.
基金The National Key R&D Program of China under contract No. 2023YFC28 11305the Scientific Research Fund of the Second Institute of Oceanography,MNR under contract No. SZ2405the Impact and Response of Antarctic Seas to Climate Change under contract No. IRASCC
文摘Research on changes in the redox conditions of bottom waters is essential for understanding deep water circulation,global ocean currents,climate change,and ecosystem health.Through sedimentary geological methods,a deeper understanding of the complex relationships between various environmental changes can be achieved,providing detailed evidence and theoretical support for global climate change research.The Ross Sea in Antarctica plays a key role in the formation of Antarctic bottom water(AABW),and the complex climate changes since the last glacial maximum(LGM)make it particularly significant for study.This research analyzes core ANT32-RB16C from the Ross Sea using geochemical proxies such as major and trace elements,grain size,and redox-sensitive indicators like Mn/Ti,Co/Ti,Mo/Ti,Cd/Ti,U/Th,and Ni/Co molar concentration ratios.Combining this data with a previously established chronological framework,the study explores the evolution of redox conditions in the Ross Sea’s deep waters since the LGM.The results show that the deep waters have remained oxygen-rich since the LGM,with significant changes in four stages.Stage 1(24.7–15.7 cal ka BP):Strong oxidizing conditions,likely due to enhanced formation of Ross Sea bottom water(RSBW),increasing oxygen levels.Stage 2(15.7–4.5 cal ka BP):Weakened oxidizing conditions as temperatures rose and ice shelves retreated,increasing primary productivity and depleting oxygen.Stage 3(4.5–1.5 cal ka BP):Continued decline in oxidizing conditions,possibly linked to high primary productivity and oxygen consumption.Stage 4(1.5 cal ka BP to present):A rapid recovery of oxidizing conditions,likely driven by temperature drops,increased RSBW formation,and decreased productivity.
基金supported by the National Key R&D Program of China(Grant No.2021YFC2802504)the National Outstanding Youth Grant(Grant No.41925027)+1 种基金the National Natural Science Foundation of China(Grant No.42206251)the Innovation Group Project of the Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(Grant No.311021008).
文摘Antarctic coastal polynyas play a vital role in atmosphere-ocean interactions and local ecosystems.This study investigates the interannual variability of springtime coastal polynyas over the Ross Sea based on satellite-retrieved sea-ice concentration(SIC)data from 1992 to 2021.Firstly,the springtime coastal polynya areas display large interannual variability as well as a positive trend of about 2000 km^(2)(10 yr)^(-1) over the 30 years.Secondly,based on composite analysis,in spring,we find that a deepened Amundsen Sea Low(ASL)induces stronger meridional winds over the eastern Ross Sea,leading to stronger sea-ice advection and expansion of coastal polynya areas.This is accompanied by more solar radiation absorption in early summer(about 16 W m^(2)),resulting in upper-ocean warming(~0.4℃)and significant sea-ice loss in late summer(~50%SIC).Additionally,the physical processes are validated by 500-year piControl simulations of a state-of-the-art Earth system model.Based on the same composite analysis,the results show that the sea-ice decline is consistent with the deepening of the ASL and the increase of the meridional sea-ice advection of the preceding spring,which is highly consistent with that of observations.This further confirms the circulations-polynyas-sea-ice physical linkages.Since the springtime ASL is strongly modulated by the tropical Pacific variability and the stratospheric polar vortex,changes in the polynya areas of the Ross Sea can be traced back to remote regions.
基金supported by the National Natural Science Foundation of China (Grant nos. 41941014 and 41930532)financially supported by National Polar Special Program “Impact and Response of Antarctic Seas to Climate Change”(Grant no. IRASCC 01-01-02E)。
文摘During the 36th Chinese National Antarctic Research Expedition,aerosol samples were gathered from the Ross Sea in Antarctic to assess the climatic impact of the Australian fires that occurred in 2019-2020.The chemical compositions,including levoglucosan(Lev)and its isomers,galactosan(Gan)and mannosan(Man),were analyzed.Principal component analysis helped identify the potential sources of these chemical components.By combining backward trajectories with the ratios of CLev/CMan and CMan/CGan,it was further inferred that Australia might be the potential source region for biomass burning.The radiative forcing resulting from biomass burning was evaluated using the Santa Barbara DISORT Atmospheric Radiative Transfer(SBDART)model,which revealed that black carbon emitted from biomass burning could slightly warm the atmosphere(+0.52 W·m^(-2))while causing slightly cooling at the surface(-0.73 W·m^(-2))and the top of the atmosphere(-0.22 W·m^(-2))over the Ross Sea.
