Tintinnid ciliates are important pelagic microplankton.Most studies previously conducted in the Amundsen Sea have covered a relatively small latitude range and provided minimal information about tintinnid species comp...Tintinnid ciliates are important pelagic microplankton.Most studies previously conducted in the Amundsen Sea have covered a relatively small latitude range and provided minimal information about tintinnid species composition and distribution.The present study was conducted to investigate tintinnid assemblages from the Antarctic zone(AZ)northward through the polar front(PF)to the subantarctic zone(SAZ).A total of 17 tintinnid species belonging to seven genera were collected,and 16 were identified.Results show that nine of the species are endemic to the Southern Ocean and they mainly inhabit the AZ near Antarctic continent with an abundant proportion exceeding 60%of total tintinnid.According to the tintinnid abundance distribution,the species were divided into four groups:Group I includes Acanthostomella norvegica,Codonellopsis glacialis,C.pusilla and Cymatocylis antarctica and mainly occurs in the northern boundary of the PF;Group II includes Cymatocylis convallaria forma calyciformis,an unidentified species,and Amphorellopsis quinquealata and mainly inhabits the PF;Group III includes Salpingella costata,Cymatocylis vanhoeffeni,C.convallaria forma cristallina,C.convallaria forma drygalskii,C.convallaria,Codonellopsis gaussi,and Laackmanniella naviculaefera and mainly occurs in the AZ near the Antarctic continent;and Group IV,which comprises Salpingella sp.and inhabits all zones.The new species of tintinnid(belonging to Group II)primarily inhabit the AZ but also are distributed in the PF,and they have large lorica-oral-diameter(LOD).The distribution ranges of tintinnid assemblages from the AZ to PF were determined,in addition to the different assemblages mixed in the PF.The information provided in this study increases our understanding of tintinnid assemblages from the Antarctic continent in the Antarctic Circumpolar Current and Antarctic waters.展开更多
The variation of the East Asian jet stream （EAJS） associated with the Eurasian （EU） teleconnection pattern is investigated using 60-yr NCEP-NCAR daily reanalysis data over the period 1951-2010.The EAJS consists of...The variation of the East Asian jet stream （EAJS） associated with the Eurasian （EU） teleconnection pattern is investigated using 60-yr NCEP-NCAR daily reanalysis data over the period 1951-2010.The EAJS consists of three components：the polar front jet （PFJ）; the plateau subtropical jet （PSJ）; and the ocean subtropical jet （OSJ）.Of these three jets over East Asia,the EU pattern exhibits a significant influence on the PFJ and OSJ.There is a simultaneous negative correlation between the EU pattern and the PFJ.A significant positive correlation is found between the EU pattern and the OSJ when the EU pattern leads the OSJ by about 5 days.There is no obvious correlation between the EU pattern and the PSJ.The positive EU phase is accompanied by a weakened and poleward-shifted PFJ,which coincides with an intensified OSJ.A possible mechanism for the variation of the EAJS during different EU phases is explored via analyzing the effects of 10-day high-and low-frequency eddy forcing.The zonal wind tendency due to high-frequency eddy forcing contributes to the simultaneous negative correlation between the EU pattern and the PFJ,as well as the northward/southward shift of the PFJ.High-and low-frequency eddy forcing are both responsible for the positive correlation between the EU pattern and the OSJ,but only high-frequency eddy forcing contributes to the lagged variation of the OSJ relative to the EU pattern.The negative correlation between the EU pattern and winter temperature and precipitation anomalies in China is maintained only when the PFJ and OSJ are out of phase with each other.Thus,the EAJS plays an important role in transmitting the EU signal to winter temperature and precipitation anomalies in China.展开更多
During the 25th Chinese National Antarctic Research Expedition, GPS radiosondes were launched to detect the atmos- pheric vertical structure over the southeast Indian Ocean frontal region. Some low-level characteristi...During the 25th Chinese National Antarctic Research Expedition, GPS radiosondes were launched to detect the atmos- pheric vertical structure over the southeast Indian Ocean frontal region. Some low-level characteristics along the cruise are studied based on in-situ observation. The observations reveal that vertical distributions of the low-level wind field and air temperature field on both sides of the Subantarctic Front are very different. A stronger （weaker） vertical gradient is on the cold （warm） side, which demonstrates that the mid-latitude ocean-atmosphere interaction is active in the southeast Indian Ocean frontal region. A low-level jet is observed over the Subantarctic Front, with speed up to 14 m＇s-1. For the Antarctic polar front, low-level wind speed near the sea surface is greater than that aloft, in contrast with the situation of the Subantarctic Front. Comparing satellite remote sensing data and widely-used reanalysis datasets with our in-situ observations, differences of varying magnitudes are found. Air temperature from Atmospheric Infrared Sounder （AIRS） data has a limited difference. The European Center for Medium Range Weather Forecasts Interim Re-Analysis （ERA Interim） dataset is much more consistent with the observations than the National Centers for Environmental Prediction/National Center for Atmospheric Research （NCEP/NCAR） Reanalysis 1 in the southeast Indian Ocean frontal region.展开更多
冬季乌拉尔山地区阻塞高压(以下简称乌山阻高)是引发东亚地区寒潮天气的重要天气系统,研究其动力机制可为实际业务工作中的极端低温事件的预测提供更多的理论参考。本文利用美国国家环境预测中心-能源部(National Centre from Environme...冬季乌拉尔山地区阻塞高压(以下简称乌山阻高)是引发东亚地区寒潮天气的重要天气系统,研究其动力机制可为实际业务工作中的极端低温事件的预测提供更多的理论参考。本文利用美国国家环境预测中心-能源部(National Centre from Environmental Prediction-Department of Energy,NCEP-DOE)的再分析数据,采用天气学方法从1979-2018年40个冬季中甄选出21次短中(生命期5~7天)及14次长生命期(生命期等于或大于8天)乌山阻高,对比分析两类阻高过程中定常热(v*T*)、动量(u*v*)通量的输送特征,结果表明:(1)冬季长生命期阻高期间60°N附近v*T*的辐合量及u*v*输送量显著大于短中生命期的,说明定常热、动量输送对阻高的长时间维持有重要作用。且长生命期阻高期间对流层上层(300~150 hPa)20°N-40°N区域u*v*向北输送,短中生命期的则向南输送,说明副热带急流向中纬度输送u*v*为阻高长时间维持提供动量补充。同时冬季长生命期阻高期间70°N极锋急流偏弱,为阻高延长生命期,扩大范围提供有利条件。(2)定常热、动量通量在对流层中上层各层次上的分布也有显著不同。各层次上的v*T*及u*v*的输送都是通过阻高激发的Rossby波波列完成的。对流层中上层(500~300 hPa)乌山阻高关键区西北-东南域定常动量通量向极补充输送是阻高长时间维持的关键。展开更多
基金supported by the National Natural Science Foundation of China(No.41576164)the National Natural Science Foundation of China(No.41876217)+4 种基金the CNRS-NSFC Joint Research Projects Program(No.41711530149)the National Key R&D Program of China(No.2017YFC14 04402)the Senior User Project of RV KEXUE(No.KE XUE2018G17)the Chinese Polar Environment Comprehensive Investigation&Assessment Programmes(No.CHINARE2016-01-05)the Scientific and Tech-nological Innovation Project by Qingdao National Laboratory for Marine Science and Technology(No.2015ASK J02)
文摘Tintinnid ciliates are important pelagic microplankton.Most studies previously conducted in the Amundsen Sea have covered a relatively small latitude range and provided minimal information about tintinnid species composition and distribution.The present study was conducted to investigate tintinnid assemblages from the Antarctic zone(AZ)northward through the polar front(PF)to the subantarctic zone(SAZ).A total of 17 tintinnid species belonging to seven genera were collected,and 16 were identified.Results show that nine of the species are endemic to the Southern Ocean and they mainly inhabit the AZ near Antarctic continent with an abundant proportion exceeding 60%of total tintinnid.According to the tintinnid abundance distribution,the species were divided into four groups:Group I includes Acanthostomella norvegica,Codonellopsis glacialis,C.pusilla and Cymatocylis antarctica and mainly occurs in the northern boundary of the PF;Group II includes Cymatocylis convallaria forma calyciformis,an unidentified species,and Amphorellopsis quinquealata and mainly inhabits the PF;Group III includes Salpingella costata,Cymatocylis vanhoeffeni,C.convallaria forma cristallina,C.convallaria forma drygalskii,C.convallaria,Codonellopsis gaussi,and Laackmanniella naviculaefera and mainly occurs in the AZ near the Antarctic continent;and Group IV,which comprises Salpingella sp.and inhabits all zones.The new species of tintinnid(belonging to Group II)primarily inhabit the AZ but also are distributed in the PF,and they have large lorica-oral-diameter(LOD).The distribution ranges of tintinnid assemblages from the AZ to PF were determined,in addition to the different assemblages mixed in the PF.The information provided in this study increases our understanding of tintinnid assemblages from the Antarctic continent in the Antarctic Circumpolar Current and Antarctic waters.
基金supported by the National Natural Science Foundation of China (Grant No. 41130963)the National Basic Research Program of China (973 Program) (Grant No. 2012CB955901)the Jiangsu Collaborative Innovation Center for Climate Change
文摘The variation of the East Asian jet stream （EAJS） associated with the Eurasian （EU） teleconnection pattern is investigated using 60-yr NCEP-NCAR daily reanalysis data over the period 1951-2010.The EAJS consists of three components：the polar front jet （PFJ）; the plateau subtropical jet （PSJ）; and the ocean subtropical jet （OSJ）.Of these three jets over East Asia,the EU pattern exhibits a significant influence on the PFJ and OSJ.There is a simultaneous negative correlation between the EU pattern and the PFJ.A significant positive correlation is found between the EU pattern and the OSJ when the EU pattern leads the OSJ by about 5 days.There is no obvious correlation between the EU pattern and the PSJ.The positive EU phase is accompanied by a weakened and poleward-shifted PFJ,which coincides with an intensified OSJ.A possible mechanism for the variation of the EAJS during different EU phases is explored via analyzing the effects of 10-day high-and low-frequency eddy forcing.The zonal wind tendency due to high-frequency eddy forcing contributes to the simultaneous negative correlation between the EU pattern and the PFJ,as well as the northward/southward shift of the PFJ.High-and low-frequency eddy forcing are both responsible for the positive correlation between the EU pattern and the OSJ,but only high-frequency eddy forcing contributes to the lagged variation of the OSJ relative to the EU pattern.The negative correlation between the EU pattern and winter temperature and precipitation anomalies in China is maintained only when the PFJ and OSJ are out of phase with each other.Thus,the EAJS plays an important role in transmitting the EU signal to winter temperature and precipitation anomalies in China.
基金supported by the National Program on Key Basic Program,Research Program of China(973 Program,Grant nos.2010CB950304 and 2012CB955601)SOA Science Fund for Young Scholars(Grant no.2011244)+2 种基金the Chinese Polar Strategy Fund(Grant no.20072017)the Chinese Polar Investigation Fund(Grant no.CHINARE 2012-01-01)the International Cooperation Fund(Grant no.JD201002)
文摘During the 25th Chinese National Antarctic Research Expedition, GPS radiosondes were launched to detect the atmos- pheric vertical structure over the southeast Indian Ocean frontal region. Some low-level characteristics along the cruise are studied based on in-situ observation. The observations reveal that vertical distributions of the low-level wind field and air temperature field on both sides of the Subantarctic Front are very different. A stronger （weaker） vertical gradient is on the cold （warm） side, which demonstrates that the mid-latitude ocean-atmosphere interaction is active in the southeast Indian Ocean frontal region. A low-level jet is observed over the Subantarctic Front, with speed up to 14 m＇s-1. For the Antarctic polar front, low-level wind speed near the sea surface is greater than that aloft, in contrast with the situation of the Subantarctic Front. Comparing satellite remote sensing data and widely-used reanalysis datasets with our in-situ observations, differences of varying magnitudes are found. Air temperature from Atmospheric Infrared Sounder （AIRS） data has a limited difference. The European Center for Medium Range Weather Forecasts Interim Re-Analysis （ERA Interim） dataset is much more consistent with the observations than the National Centers for Environmental Prediction/National Center for Atmospheric Research （NCEP/NCAR） Reanalysis 1 in the southeast Indian Ocean frontal region.
文摘冬季乌拉尔山地区阻塞高压(以下简称乌山阻高)是引发东亚地区寒潮天气的重要天气系统,研究其动力机制可为实际业务工作中的极端低温事件的预测提供更多的理论参考。本文利用美国国家环境预测中心-能源部(National Centre from Environmental Prediction-Department of Energy,NCEP-DOE)的再分析数据,采用天气学方法从1979-2018年40个冬季中甄选出21次短中(生命期5~7天)及14次长生命期(生命期等于或大于8天)乌山阻高,对比分析两类阻高过程中定常热(v*T*)、动量(u*v*)通量的输送特征,结果表明:(1)冬季长生命期阻高期间60°N附近v*T*的辐合量及u*v*输送量显著大于短中生命期的,说明定常热、动量输送对阻高的长时间维持有重要作用。且长生命期阻高期间对流层上层(300~150 hPa)20°N-40°N区域u*v*向北输送,短中生命期的则向南输送,说明副热带急流向中纬度输送u*v*为阻高长时间维持提供动量补充。同时冬季长生命期阻高期间70°N极锋急流偏弱,为阻高延长生命期,扩大范围提供有利条件。(2)定常热、动量通量在对流层中上层各层次上的分布也有显著不同。各层次上的v*T*及u*v*的输送都是通过阻高激发的Rossby波波列完成的。对流层中上层(500~300 hPa)乌山阻高关键区西北-东南域定常动量通量向极补充输送是阻高长时间维持的关键。
