This study uses linear regression and composite analyses to identify a pronounced asymmetric connection of sea surface temperature(SST)in the Tasman Sea with the two opposite phases of El Ni?o-Southern Oscillation(ENS...This study uses linear regression and composite analyses to identify a pronounced asymmetric connection of sea surface temperature(SST)in the Tasman Sea with the two opposite phases of El Ni?o-Southern Oscillation(ENSO)during austral summer.In El Ni?o years,the SST anomalies(SSTAs)in the Tasman Sea exhibit a dipolar pattern with weak warmth in the northwest and modest cooling in the southeast,while during La Ni?a years the SSTAs exhibit a basin-scale warmth with greater amplitude.Investigations into the underlying mechanism suggest that this asymmetry arises from a mechanism related to oceanic heat transport,specifically the anomalous Ekman meridional heat transport induced by the zonal wind stress anomalies,rather than the surface heat fluxes on the air-sea interface.Further analysis reveals that the asymmetry of oceanic heat transport between El Ni?o and La Ni?a years is driven by the asymmetric atmospheric circulation over the Tasman Sea stimulated by the asymmetric diabatic heating in the tropical Pacific between the two opposite ENSO phases.展开更多
The ENSO-induced PacificeSouth America(PSA)pattern is an important atmospheric bridge in linking the Antarctic climate to the tropical Pacific.The AGCM simulated PSA-like responses to ENSO are evidently weaker than th...The ENSO-induced PacificeSouth America(PSA)pattern is an important atmospheric bridge in linking the Antarctic climate to the tropical Pacific.The AGCM simulated PSA-like responses to ENSO are evidently weaker than the observed in terms of its intensity due to the lack of airesea coupling processes.The Tasman Sea features active airesea interactions.However,how and to what extent the airesea coupling explains the deficiency of the AGCM responses to ENSO is unclear.In this study,the role of the airesea coupling elsewhere the tropical Pacific in shaping the ENSOeSouth Pacific teleconnection is first estimated by comparing the coupled tropical Pacific pacemaker experiments(PACE)derived from the Community Earth System Model version 1(CESM1)and the parallel Pacific OceaneGlobal Atmosphere experiments(POGA)with the same atmospheric component model of CESM1.Our results suggest that the airesea coupling elsewhere the tropical Pacific greatly intensifies the South Pacific atmospheric response to ENSO.Then the separated impact of airesea coupling over the Tasman Sea is stressed with another set of AGCM experiments forced with the PACE sea surface temperature(SST)outputs in the Tasman Sea.The results show that the atmospheric response to the SST anomalies in the Tasman Sea bears a remarkable resemblance to that due to the airesea coupling elsewhere the tropical Pacific,and explains about 30%of the intensified amplitude.This highlights a substantial contribution of the airesea coupling over the Tasman Sea to intensifying the extratropical South Pacific atmospheric responses to ENSO,and provides a new perspective on the connection between tropical Pacific and Antarctic climate change.展开更多
Southern Hemisphere mid-latitude westerlies contribute to the ventilation of the deep Southern Ocean(SO),and drive changes in atmospheric carbon dioxide(CO2) and the global climate.As the westerlies control directly o...Southern Hemisphere mid-latitude westerlies contribute to the ventilation of the deep Southern Ocean(SO),and drive changes in atmospheric carbon dioxide(CO2) and the global climate.As the westerlies control directly oceanic fronts,the movement of the subtropical front(STF) reflects the westerlies migration.Thus it is important to understand the relationships between STF movement and the weaterlies,ventilation of the deep SO,ice volume and atmospheric CO2.To this end,we use two new high-resolution records from early Marine Isotope Stage(MIS) 20(～800 ka) of sea surface temperature(SST) based on U k' 37 paleo-thermometer and benthic oxygen isotope(δ 18OB) at Ocean Drilling Program(ODP) Site 1170B in the southern Tasman Sea(STS),to construct linkages between the marine records and atmospheric proxies from Antarctic ice-cores.During the last 800 ka,the average SST(10.2℃) at Site 1170B is 1.8℃ lower than today(annual average 12℃).The highest average SST of 11.6℃ occurred during MIS 1,and the lowest average SST of 7.8℃ occurred during MIS 2.The warmest and coldest records of 14.7℃ and 6.2℃ occurred in the MIS 5 and MIS 2,respectively.In the glacial-interglacial cycles of the last 800 ka,variability of reconstructed SST shows that the STF moved northward or southward more than 3° of latitude compared with its present location.In the warmest stage MIS 5,the STF shifted to its southernmost location of ～49°S.In contrast,in the coldest stage MIS 2,the STF moved to its northernmost location of ～43°S.In response to orbital cycles,the westerlies movement led ice volume and atmospheric CO2 changes,but it was in phase with change in Antarctic atmospheric temperature.Ice volume only preceded atmospheric CO2 only a little at the 23-ka precession band,lagged the atmospheric CO2 at the 100-ka eccentricity band,and was in phase with atmospheric CO2 at the 40-ka obliquity band.展开更多
塔斯曼海位于西南太平洋地区,处于印度-澳大利亚板块和西兰板块之间,大地构造背景复杂。该地区是全球油气资源勘探的重点海域之一,但是国内对该地区的研究相当匮乏。本文根据塔斯曼海海域的自由空气重力异常对塔斯曼海海域的构造单元进...塔斯曼海位于西南太平洋地区,处于印度-澳大利亚板块和西兰板块之间,大地构造背景复杂。该地区是全球油气资源勘探的重点海域之一,但是国内对该地区的研究相当匮乏。本文根据塔斯曼海海域的自由空气重力异常对塔斯曼海海域的构造单元进行了划分,前人关于塔斯曼海的研究主要集中在Resolution海岭北部,我们认为塔斯曼海的范围应包括Resolution海岭以南,麦夸里海岭以西,塔斯曼断裂带以东的区域(即南部次盆)。结果显示,塔斯曼海域及邻区包括3个一级构造单元:东澳大利亚陆缘、西兰板块和塔斯曼海盆,且塔斯曼海盆可进一步划分为西部次盆、东部次盆和南部次盆。本文基于塔斯曼海域90 Ma以来的洋壳年龄数据编制了构造演化图,将塔斯曼海的形成演化过程分为4个阶段:(1)中生代陆内裂谷期(90～83 Ma BP);(2)塔斯曼海扩张阶段(83～61 Ma BP);(3)塔斯曼海北部扩张停止阶段(61～52 Ma BP);(4)塔斯曼海南部改造阶段(52 Ma BP至今)。展开更多
基金jointly supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA19070402)the National Natural Science Foundation of China(Grant Nos.41790473 and 41731177)。
文摘This study uses linear regression and composite analyses to identify a pronounced asymmetric connection of sea surface temperature(SST)in the Tasman Sea with the two opposite phases of El Ni?o-Southern Oscillation(ENSO)during austral summer.In El Ni?o years,the SST anomalies(SSTAs)in the Tasman Sea exhibit a dipolar pattern with weak warmth in the northwest and modest cooling in the southeast,while during La Ni?a years the SSTAs exhibit a basin-scale warmth with greater amplitude.Investigations into the underlying mechanism suggest that this asymmetry arises from a mechanism related to oceanic heat transport,specifically the anomalous Ekman meridional heat transport induced by the zonal wind stress anomalies,rather than the surface heat fluxes on the air-sea interface.Further analysis reveals that the asymmetry of oceanic heat transport between El Ni?o and La Ni?a years is driven by the asymmetric atmospheric circulation over the Tasman Sea stimulated by the asymmetric diabatic heating in the tropical Pacific between the two opposite ENSO phases.
基金This work was supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA19070402)the National Natural Science Foundation of China(41790473)the National Key Research and Development Program of China(2019YFC1510105).
文摘The ENSO-induced PacificeSouth America(PSA)pattern is an important atmospheric bridge in linking the Antarctic climate to the tropical Pacific.The AGCM simulated PSA-like responses to ENSO are evidently weaker than the observed in terms of its intensity due to the lack of airesea coupling processes.The Tasman Sea features active airesea interactions.However,how and to what extent the airesea coupling explains the deficiency of the AGCM responses to ENSO is unclear.In this study,the role of the airesea coupling elsewhere the tropical Pacific in shaping the ENSOeSouth Pacific teleconnection is first estimated by comparing the coupled tropical Pacific pacemaker experiments(PACE)derived from the Community Earth System Model version 1(CESM1)and the parallel Pacific OceaneGlobal Atmosphere experiments(POGA)with the same atmospheric component model of CESM1.Our results suggest that the airesea coupling elsewhere the tropical Pacific greatly intensifies the South Pacific atmospheric response to ENSO.Then the separated impact of airesea coupling over the Tasman Sea is stressed with another set of AGCM experiments forced with the PACE sea surface temperature(SST)outputs in the Tasman Sea.The results show that the atmospheric response to the SST anomalies in the Tasman Sea bears a remarkable resemblance to that due to the airesea coupling elsewhere the tropical Pacific,and explains about 30%of the intensified amplitude.This highlights a substantial contribution of the airesea coupling over the Tasman Sea to intensifying the extratropical South Pacific atmospheric responses to ENSO,and provides a new perspective on the connection between tropical Pacific and Antarctic climate change.
基金supported by the National Natural Science Foundation of China (40321603 and 40676030)the National Basic Research Program of China (2007CB815903)the Chinese IPY Program (2007–2009)
文摘Southern Hemisphere mid-latitude westerlies contribute to the ventilation of the deep Southern Ocean(SO),and drive changes in atmospheric carbon dioxide(CO2) and the global climate.As the westerlies control directly oceanic fronts,the movement of the subtropical front(STF) reflects the westerlies migration.Thus it is important to understand the relationships between STF movement and the weaterlies,ventilation of the deep SO,ice volume and atmospheric CO2.To this end,we use two new high-resolution records from early Marine Isotope Stage(MIS) 20(～800 ka) of sea surface temperature(SST) based on U k' 37 paleo-thermometer and benthic oxygen isotope(δ 18OB) at Ocean Drilling Program(ODP) Site 1170B in the southern Tasman Sea(STS),to construct linkages between the marine records and atmospheric proxies from Antarctic ice-cores.During the last 800 ka,the average SST(10.2℃) at Site 1170B is 1.8℃ lower than today(annual average 12℃).The highest average SST of 11.6℃ occurred during MIS 1,and the lowest average SST of 7.8℃ occurred during MIS 2.The warmest and coldest records of 14.7℃ and 6.2℃ occurred in the MIS 5 and MIS 2,respectively.In the glacial-interglacial cycles of the last 800 ka,variability of reconstructed SST shows that the STF moved northward or southward more than 3° of latitude compared with its present location.In the warmest stage MIS 5,the STF shifted to its southernmost location of ～49°S.In contrast,in the coldest stage MIS 2,the STF moved to its northernmost location of ～43°S.In response to orbital cycles,the westerlies movement led ice volume and atmospheric CO2 changes,but it was in phase with change in Antarctic atmospheric temperature.Ice volume only preceded atmospheric CO2 only a little at the 23-ka precession band,lagged the atmospheric CO2 at the 100-ka eccentricity band,and was in phase with atmospheric CO2 at the 40-ka obliquity band.
文摘塔斯曼海位于西南太平洋地区,处于印度-澳大利亚板块和西兰板块之间,大地构造背景复杂。该地区是全球油气资源勘探的重点海域之一,但是国内对该地区的研究相当匮乏。本文根据塔斯曼海海域的自由空气重力异常对塔斯曼海海域的构造单元进行了划分,前人关于塔斯曼海的研究主要集中在Resolution海岭北部,我们认为塔斯曼海的范围应包括Resolution海岭以南,麦夸里海岭以西,塔斯曼断裂带以东的区域(即南部次盆)。结果显示,塔斯曼海域及邻区包括3个一级构造单元:东澳大利亚陆缘、西兰板块和塔斯曼海盆,且塔斯曼海盆可进一步划分为西部次盆、东部次盆和南部次盆。本文基于塔斯曼海域90 Ma以来的洋壳年龄数据编制了构造演化图,将塔斯曼海的形成演化过程分为4个阶段:(1)中生代陆内裂谷期(90～83 Ma BP);(2)塔斯曼海扩张阶段(83～61 Ma BP);(3)塔斯曼海北部扩张停止阶段(61～52 Ma BP);(4)塔斯曼海南部改造阶段(52 Ma BP至今)。
