本文基于Hadley中心的海表温度资料、全国160站气温资料以及National Centers for Environmental Prediction/National Center for Atmospheric Research(NCEP/NCAR)的再分析资料,运用经验正交函数(empirical orthogonal function,EOF)...本文基于Hadley中心的海表温度资料、全国160站气温资料以及National Centers for Environmental Prediction/National Center for Atmospheric Research(NCEP/NCAR)的再分析资料,运用经验正交函数(empirical orthogonal function,EOF)分解和相关分析等多种统计方法,研究了1951~2020年秋季(9~11月)北大西洋海温年际异常的主要特征及其对初冬(12月)我国气温异常的影响。结果表明:秋季北大西洋海温异常EOF的第一模态是纽芬兰岛东南部海温为负(正)距平,北大西洋副极地和副热带及其东部海温为正(负)距平的马蹄型海温模态,方差贡献率为20.5%。研究表明,秋季北大西洋马蹄型海温异常与我国大部分地区初冬气温异常有显著的正相关关系,即秋季北大西洋马蹄型海温模态呈正位相时,我国大部分地区初冬气温偏高,反之,我国大部分地区初冬气温偏低。进一步分析表明,秋季北大西洋马蹄型海温异常能够持续到初冬。当秋季北大西洋马蹄型海温呈正(负)位相时,初冬北大西洋副极地和副热带海温异常通过加热(冷却)异常能够引起局地对流层上层的辐散(辐合)运动,并且激发出南、北两支Rossby波列。其中,北支波列由北大西洋副极地向东北方向传播至巴伦支海附近,然后沿西伯利亚向东南方向传播至我国上空;南支波列由北大西洋副热带向东传播至我国上空。在南、北支波列的影响下,我国上空对流层上层出现异常辐合(辐散),与之伴随的异常下沉(上升)运动使得我国上空云量减少(增加),到达地表的短波辐射增加(减少),同时地表向低层大气传输的长波辐射增加(减少),在非绝热加热的作用下,我国大部分地区气温偏高(偏低)。利用NCAR Community Atmosphere Model version 5.3(CAM5.3)模式模拟了北大西洋马蹄型海温异常对初冬大气环流、辐射强迫和气温的影响,模拟结果与观测资料统计分析结果基本一致,进一步表明该海温�展开更多
A strong （weak） East Asian summer monsoon （EASM） is usually concurrent with the tripole pattern of North Atlantic SST anomalies on the interannual timescale during summer, which has positive （negative） SST anoma...A strong （weak） East Asian summer monsoon （EASM） is usually concurrent with the tripole pattern of North Atlantic SST anomalies on the interannual timescale during summer, which has positive （negative） SST anomalies in the northwestern North Atlantic and negative （positive） SST anomalies in the subpolar and tropical ocean. The mechanisms responsible for this linkage are diagnosed in the present study. It is shown that a barotropie wave-train pattern occurring over the Atlantic-Eurasia region likely acts as a link between the EASM and the SST tripole during summer. This wave-train pattern is concurrent with geopotential height anomalies over the Ural Mountains, which has a substantial effect on the EASM. Diagnosis based on observations and linear dynamical model results reveals that the mechanism for maintaining the wave-train pattern involves both the anomalous diabatic heating and synoptic eddy-vorticity forcing. Since the North Atlantic SST tripole is closely coupled with the North Atlantic Oscillation （NAO）, the relationships between these two factors and the EASM are also examined. It is found that the connection of the EASM with the summer SST tripole is sensitive to the meridional location of the tripole, which is characterized by large seasonal variations due to the north-south movement of the activity centers of the NAO. The SST tripole that has a strong relationship with the EASM appears to be closely coupled with the NAO in the previous spring rather than in the simultaneous summer.展开更多
The effect of solar wind（SW） on the North Atlantic sea surface temperature（SST） in boreal winter is examined through an analysis of observational data during 1964-2013.The North Atlantic SSTs show a pronounced mer...The effect of solar wind（SW） on the North Atlantic sea surface temperature（SST） in boreal winter is examined through an analysis of observational data during 1964-2013.The North Atlantic SSTs show a pronounced meridional tripolar pattern in response to solar wind speed（SWS） variations.This pattern is broadly similar to the leading empirical orthogonal function（EOF） mode of interannual variations in the wintertime SSTs over North Atlantic.The time series of this leading EOF mode of SST shows a significant interannual period,which is the same as that of wintertime SWS.This response also appears as a compact north-south seesaw of sea level pressure and a vertical tripolar structure of zonal wind,which simultaneously resembles the North Atlantic Oscillation（NAO） in the overlying atmosphere.As compared with the typical low SWS winters,during the typical high SWS winters,the stratospheric polar night jet（PNJ） is evidently enhanced and extends from the stratosphere to the troposphere,even down to the North Atlantic Ocean surface.Notably,the North Atlantic Ocean is an exclusive region in which the SW signal spreads downward from the stratosphere to the troposphere.Thus,it seems that the SW is a possible factor for this North Atlantic SST tripolar mode.The dynamical process of stratosphere-troposphere coupling,together with the global atmospheric electric circuit-cloud microphysical process,probably accounts for the particular downward propagation of the SW signal.展开更多
This study employed proxy data to investigate the phase relationship between the North Atlantic deep-level temperature and the Qinghai-Tibet Plateau(TP)surface air temperature(TP temperature)and its evolution at the m...This study employed proxy data to investigate the phase relationship between the North Atlantic deep-level temperature and the Qinghai-Tibet Plateau(TP)surface air temperature(TP temperature)and its evolution at the millennial scale since the Last Interglaciation.The results indicate the alternation of in-phase and anti-phase relationships since the Last Interglaciation,with the in-phase relationships showing a shorter duration than the anti-phase relationships.Alternations between the in-phase and antiphase relationships occurred more frequently during the Last Interglaciation than during the Last Glaciation.The phase relationship between the North Atlantic deep-level temperature and the TP temperature was broadly illustrated by that between the North Atlantic temperature(based on oxygen isotope data from the Greenland ice core)and TP temperature.Furthermore,the North Atlantic deep-level temperature and the TP temperature may be connected through the North Atlantic sea surface temperature.展开更多
文摘本文基于Hadley中心的海表温度资料、全国160站气温资料以及National Centers for Environmental Prediction/National Center for Atmospheric Research(NCEP/NCAR)的再分析资料,运用经验正交函数(empirical orthogonal function,EOF)分解和相关分析等多种统计方法,研究了1951~2020年秋季(9~11月)北大西洋海温年际异常的主要特征及其对初冬(12月)我国气温异常的影响。结果表明:秋季北大西洋海温异常EOF的第一模态是纽芬兰岛东南部海温为负(正)距平,北大西洋副极地和副热带及其东部海温为正(负)距平的马蹄型海温模态,方差贡献率为20.5%。研究表明,秋季北大西洋马蹄型海温异常与我国大部分地区初冬气温异常有显著的正相关关系,即秋季北大西洋马蹄型海温模态呈正位相时,我国大部分地区初冬气温偏高,反之,我国大部分地区初冬气温偏低。进一步分析表明,秋季北大西洋马蹄型海温异常能够持续到初冬。当秋季北大西洋马蹄型海温呈正(负)位相时,初冬北大西洋副极地和副热带海温异常通过加热(冷却)异常能够引起局地对流层上层的辐散(辐合)运动,并且激发出南、北两支Rossby波列。其中,北支波列由北大西洋副极地向东北方向传播至巴伦支海附近,然后沿西伯利亚向东南方向传播至我国上空;南支波列由北大西洋副热带向东传播至我国上空。在南、北支波列的影响下,我国上空对流层上层出现异常辐合(辐散),与之伴随的异常下沉(上升)运动使得我国上空云量减少(增加),到达地表的短波辐射增加(减少),同时地表向低层大气传输的长波辐射增加(减少),在非绝热加热的作用下,我国大部分地区气温偏高(偏低)。利用NCAR Community Atmosphere Model version 5.3(CAM5.3)模式模拟了北大西洋马蹄型海温异常对初冬大气环流、辐射强迫和气温的影响,模拟结果与观测资料统计分析结果基本一致,进一步表明该海温�
基金jointly supported by the National Basic Research Program of China (Grant Nos. 2010CB950404, 2013CB430203, 2010CB950501 and 2012CB955901)the National Natural Science Foundation of China (Grant No. 41205058)+1 种基金the China Postdoctoral Science Foundation (Grant No. 2012M510634)the National Science and Technology Support Program of China (Grant No. 2009BAC51B05)
文摘A strong （weak） East Asian summer monsoon （EASM） is usually concurrent with the tripole pattern of North Atlantic SST anomalies on the interannual timescale during summer, which has positive （negative） SST anomalies in the northwestern North Atlantic and negative （positive） SST anomalies in the subpolar and tropical ocean. The mechanisms responsible for this linkage are diagnosed in the present study. It is shown that a barotropie wave-train pattern occurring over the Atlantic-Eurasia region likely acts as a link between the EASM and the SST tripole during summer. This wave-train pattern is concurrent with geopotential height anomalies over the Ural Mountains, which has a substantial effect on the EASM. Diagnosis based on observations and linear dynamical model results reveals that the mechanism for maintaining the wave-train pattern involves both the anomalous diabatic heating and synoptic eddy-vorticity forcing. Since the North Atlantic SST tripole is closely coupled with the North Atlantic Oscillation （NAO）, the relationships between these two factors and the EASM are also examined. It is found that the connection of the EASM with the summer SST tripole is sensitive to the meridional location of the tripole, which is characterized by large seasonal variations due to the north-south movement of the activity centers of the NAO. The SST tripole that has a strong relationship with the EASM appears to be closely coupled with the NAO in the previous spring rather than in the simultaneous summer.
基金Supported by the National(Key)Basic Research and Development(973)Program of China(2012CB957804)National Natural Science Foundation of China(41490642 and 41375069)
文摘The effect of solar wind（SW） on the North Atlantic sea surface temperature（SST） in boreal winter is examined through an analysis of observational data during 1964-2013.The North Atlantic SSTs show a pronounced meridional tripolar pattern in response to solar wind speed（SWS） variations.This pattern is broadly similar to the leading empirical orthogonal function（EOF） mode of interannual variations in the wintertime SSTs over North Atlantic.The time series of this leading EOF mode of SST shows a significant interannual period,which is the same as that of wintertime SWS.This response also appears as a compact north-south seesaw of sea level pressure and a vertical tripolar structure of zonal wind,which simultaneously resembles the North Atlantic Oscillation（NAO） in the overlying atmosphere.As compared with the typical low SWS winters,during the typical high SWS winters,the stratospheric polar night jet（PNJ） is evidently enhanced and extends from the stratosphere to the troposphere,even down to the North Atlantic Ocean surface.Notably,the North Atlantic Ocean is an exclusive region in which the SW signal spreads downward from the stratosphere to the troposphere.Thus,it seems that the SW is a possible factor for this North Atlantic SST tripolar mode.The dynamical process of stratosphere-troposphere coupling,together with the global atmospheric electric circuit-cloud microphysical process,probably accounts for the particular downward propagation of the SW signal.
基金supported by the Special Foundation for the National Science and Technology Major Project of China(2011FY120300)the National Natural Science Foundation of China(41001058)
文摘This study employed proxy data to investigate the phase relationship between the North Atlantic deep-level temperature and the Qinghai-Tibet Plateau(TP)surface air temperature(TP temperature)and its evolution at the millennial scale since the Last Interglaciation.The results indicate the alternation of in-phase and anti-phase relationships since the Last Interglaciation,with the in-phase relationships showing a shorter duration than the anti-phase relationships.Alternations between the in-phase and antiphase relationships occurred more frequently during the Last Interglaciation than during the Last Glaciation.The phase relationship between the North Atlantic deep-level temperature and the TP temperature was broadly illustrated by that between the North Atlantic temperature(based on oxygen isotope data from the Greenland ice core)and TP temperature.Furthermore,the North Atlantic deep-level temperature and the TP temperature may be connected through the North Atlantic sea surface temperature.
