利用美国国家环境预测中心与国家大气研究中心(NCEP/NCAR)逐日再分析资料,针对北大西洋多年代际振荡(AMO)两个不同位相,对逐候200 h Pa经向风异常进行EOF分析,发现在AMO正、负位相期间,欧亚副热带波列的季节内活动存在明显差异。利用超...利用美国国家环境预测中心与国家大气研究中心(NCEP/NCAR)逐日再分析资料,针对北大西洋多年代际振荡(AMO)两个不同位相,对逐候200 h Pa经向风异常进行EOF分析,发现在AMO正、负位相期间,欧亚副热带波列的季节内活动存在明显差异。利用超前—滞后回归,对比了不同AMO位相下副热带波列及其相联系的印度夏季降水的季节内活动演变特征,分析有关的大气环流,探究波列影响降水的机制。结果表明:在AMO负位相期间,由格陵兰岛以南北大西洋经大不列颠岛、地中海、黑海—里海向南亚北部传播的副热带波列的季节内演变,在印度中部引起下沉,导致中部及西北部季节内降水减少,波列负位相相反;在AMO正位相期间,副热带波列西起冰岛以南北大西洋经丹麦南部、俄罗斯西部、中亚向南亚东北部传播,对应该波列的季节内演变,辐合上升区在印度中部和东西两侧,使得该区域季节内降水增加,波列负位相相反。于是,AMO通过调制夏季欧亚副热带波列的季节内活动,可以对印度夏季降水的季节内变化空间型及演变发挥显著影响。展开更多
本文基于地面观测资料和NCEP/NCAR再分析数据,利用经验正交函数分析、线性回归分析等方法对1960—2016年夏季(6—8月)长江流域的极端高温(Extreme High Temperature,EHT)事件的强度、暖昼、暖夜发生日数的年代际特征及其对应大气环流进...本文基于地面观测资料和NCEP/NCAR再分析数据,利用经验正交函数分析、线性回归分析等方法对1960—2016年夏季(6—8月)长江流域的极端高温(Extreme High Temperature,EHT)事件的强度、暖昼、暖夜发生日数的年代际特征及其对应大气环流进行分析,并探讨了EHT事件与大西洋多年代际振荡(Atlantic Multidecadal Oscillation,AMO)的关系。结果表明,中国夏季长江流域的极端高温事件存在明显的年代际变化特征,其中1960—1970年和2002—2016年为暖时期,1971—2001年为冷时期。相较于冷时期,暖时期在高温强度、暖昼和暖夜的发生日数方面均明显偏暖。针对于该极端高温年代际特征的成因,研究结果表明,暖时期位于长江流域北部的对流层中高层异常反气旋和偏北偏西的西太平洋副高有利于该地区下沉运动的增强,进而有利于极端高温的出现。同时,在对流层低层,位于中国东部的异常反气旋将低纬地区的暖湿气流携带至长江流域,这也有利于长江流域EHT事件的发生。此外,进一步分析表明,AMO与长江流域夏季EHT事件在年代际尺度上存在明显的关系,AMO超前中国夏季长江流域的EHT事件6~8 a,这对预测中国长江流域极端高温事件具有一定的指示作用。展开更多
海洋热浪是发生在海洋上的极端高温事件,对海洋环境和生态系统具有破坏性影响。文章采用1960—2020年第五代欧洲中期天气预报中心再分析资料(European centre for medium-range weather forecasts reanalysis v5,ERA5)和英国气象局哈德...海洋热浪是发生在海洋上的极端高温事件,对海洋环境和生态系统具有破坏性影响。文章采用1960—2020年第五代欧洲中期天气预报中心再分析资料(European centre for medium-range weather forecasts reanalysis v5,ERA5)和英国气象局哈德来中心全球海冰和海洋表面温度资料集(Hadley centre global sea ie and sea surface temperature,HadISST)以及地球系统模式(community Earth system model,CESM1)北大西洋理想试验数据等,通过相关、合成分析等多种统计方法,研究了厄尔尼诺–南方涛动(El Niño-Southern Oscillation,ENSO)与次年初夏西太平洋海洋热浪年际关系的变化特征,并进一步探讨了二者关系发生年代际变化的可能成因。研究结果表明:1)ENSO与次年初夏西太平洋海洋热浪月数的年际关系具有明显的年代际变化特征,北大西洋多年代际振荡(Atantic multidecadal oscillation,AMO)是二者年际关系发生年代际变化的主要成因。当AMO处于正位相时,ENSO与次年初夏西太平洋海洋热浪存在显著的正相关关系,而当AMO处于负位相时,上述二者相关关系不再显著;2)AMO主要通过调控ENSO事件的强度进而影响西北太平洋大气环流的异常响应,从而进一步影响ENSO与次年初夏西太平洋海洋热浪之间的关系。当AMO处于负(正)位相时,相对较强(弱)的ENSO事件通过强(弱)风–蒸发–海温正反馈过程,使得ENSO事件次年初夏西北太平洋地区产生位置相对偏东(西)、强度相对偏强(弱)的异常反气旋/气旋。异常反气旋/气旋的位置和强度导致初夏西太平洋海洋热浪的分布在AMO正、负位相存在显著差异。展开更多
The interdecadal circumglobal teleconnection （ID-CGT） pattern is the dominant circulation mode over the NH during boreal summer on the interdecadal time scale. Its temporal evolution is synchronous with that of the ...The interdecadal circumglobal teleconnection （ID-CGT） pattern is the dominant circulation mode over the NH during boreal summer on the interdecadal time scale. Its temporal evolution is synchronous with that of the Atlantic Multidecadal Oscillation （AMO）. In this study, through analyzing the results of sensitivity experiments using five AGCMs driven by specified AMO-related SST anomalies （SSTAs） in the North Atlantic, the authors investigate whether the ID-CGT is excited by the AMO. Two out of the five models simulate the barotropic stationary wave pattern located along the westerly jet, suggesting that the ID-CGT pattern should be excited, at least partially, by the AMO- related SSTAs. Model results suggest that the ID-CGT pattern plays a role in linking the AMO and NH summer land SAT perturbations on the interdecadal time scale.展开更多
The internal modes of the North Pacific can lead to climatic oscillations through ocean-atmosphere interactions and induce global climate responses.The best example is the Pacific Decadal Oscillation, but this fails t...The internal modes of the North Pacific can lead to climatic oscillations through ocean-atmosphere interactions and induce global climate responses.The best example is the Pacific Decadal Oscillation, but this fails to explain many climate phenomena. Here, another multidecadal variability over the North Pacific is described, found by analyzing reconstructed data covering the past 140 years. It is named the Pacific Multidecadal Oscillation （PMO）, with anomalously high/low SSTs over the northeastern Pacific, and a quasi-60-year cycle. Related to this low-frequency variability of SST, the global mean temperature and precipitation present significant interdecadal differences. More importantly, the PMO index leads the global mean surface air temperature and SST by one to three years. The Arctic Oscillation pattern and atmospheric circulations are shown to change substantially with the transition of the PMO mode from positive to negative phases. This multidecadal oscillation improves the prospect for a long-term forecast of the global warming trend, since the PMO bears a remarkable relationship with global temperature.展开更多
文摘利用美国国家环境预测中心与国家大气研究中心(NCEP/NCAR)逐日再分析资料,针对北大西洋多年代际振荡(AMO)两个不同位相,对逐候200 h Pa经向风异常进行EOF分析,发现在AMO正、负位相期间,欧亚副热带波列的季节内活动存在明显差异。利用超前—滞后回归,对比了不同AMO位相下副热带波列及其相联系的印度夏季降水的季节内活动演变特征,分析有关的大气环流,探究波列影响降水的机制。结果表明:在AMO负位相期间,由格陵兰岛以南北大西洋经大不列颠岛、地中海、黑海—里海向南亚北部传播的副热带波列的季节内演变,在印度中部引起下沉,导致中部及西北部季节内降水减少,波列负位相相反;在AMO正位相期间,副热带波列西起冰岛以南北大西洋经丹麦南部、俄罗斯西部、中亚向南亚东北部传播,对应该波列的季节内演变,辐合上升区在印度中部和东西两侧,使得该区域季节内降水增加,波列负位相相反。于是,AMO通过调制夏季欧亚副热带波列的季节内活动,可以对印度夏季降水的季节内变化空间型及演变发挥显著影响。
文摘海洋热浪是发生在海洋上的极端高温事件,对海洋环境和生态系统具有破坏性影响。文章采用1960—2020年第五代欧洲中期天气预报中心再分析资料(European centre for medium-range weather forecasts reanalysis v5,ERA5)和英国气象局哈德来中心全球海冰和海洋表面温度资料集(Hadley centre global sea ie and sea surface temperature,HadISST)以及地球系统模式(community Earth system model,CESM1)北大西洋理想试验数据等,通过相关、合成分析等多种统计方法,研究了厄尔尼诺–南方涛动(El Niño-Southern Oscillation,ENSO)与次年初夏西太平洋海洋热浪年际关系的变化特征,并进一步探讨了二者关系发生年代际变化的可能成因。研究结果表明:1)ENSO与次年初夏西太平洋海洋热浪月数的年际关系具有明显的年代际变化特征,北大西洋多年代际振荡(Atantic multidecadal oscillation,AMO)是二者年际关系发生年代际变化的主要成因。当AMO处于正位相时,ENSO与次年初夏西太平洋海洋热浪存在显著的正相关关系,而当AMO处于负位相时,上述二者相关关系不再显著;2)AMO主要通过调控ENSO事件的强度进而影响西北太平洋大气环流的异常响应,从而进一步影响ENSO与次年初夏西太平洋海洋热浪之间的关系。当AMO处于负(正)位相时,相对较强(弱)的ENSO事件通过强(弱)风–蒸发–海温正反馈过程,使得ENSO事件次年初夏西北太平洋地区产生位置相对偏东(西)、强度相对偏强(弱)的异常反气旋/气旋。异常反气旋/气旋的位置和强度导致初夏西太平洋海洋热浪的分布在AMO正、负位相存在显著差异。
基金supported by the National Basic Research Program of China[grant number 2012CB955202]the National Natural Science Foundation of China[grant numbers 41005040 and 41023002]the R&D Special Fund for Public Welfare Industry(Meteorology)[grant number GYHY201506012]
文摘The interdecadal circumglobal teleconnection （ID-CGT） pattern is the dominant circulation mode over the NH during boreal summer on the interdecadal time scale. Its temporal evolution is synchronous with that of the Atlantic Multidecadal Oscillation （AMO）. In this study, through analyzing the results of sensitivity experiments using five AGCMs driven by specified AMO-related SST anomalies （SSTAs） in the North Atlantic, the authors investigate whether the ID-CGT is excited by the AMO. Two out of the five models simulate the barotropic stationary wave pattern located along the westerly jet, suggesting that the ID-CGT pattern should be excited, at least partially, by the AMO- related SSTAs. Model results suggest that the ID-CGT pattern plays a role in linking the AMO and NH summer land SAT perturbations on the interdecadal time scale.
基金supported by the National Natural Science Foundation of China[grant number 41421004],[grant number41130103]
文摘The internal modes of the North Pacific can lead to climatic oscillations through ocean-atmosphere interactions and induce global climate responses.The best example is the Pacific Decadal Oscillation, but this fails to explain many climate phenomena. Here, another multidecadal variability over the North Pacific is described, found by analyzing reconstructed data covering the past 140 years. It is named the Pacific Multidecadal Oscillation （PMO）, with anomalously high/low SSTs over the northeastern Pacific, and a quasi-60-year cycle. Related to this low-frequency variability of SST, the global mean temperature and precipitation present significant interdecadal differences. More importantly, the PMO index leads the global mean surface air temperature and SST by one to three years. The Arctic Oscillation pattern and atmospheric circulations are shown to change substantially with the transition of the PMO mode from positive to negative phases. This multidecadal oscillation improves the prospect for a long-term forecast of the global warming trend, since the PMO bears a remarkable relationship with global temperature.
