Both correlation analysis and case study indi-cate that Antarctic oscillation (AAO) is closely related withsummer rainfall in eastern China. When AAO is stronger inboreal spring, especially in May, there is more mei-y...Both correlation analysis and case study indi-cate that Antarctic oscillation (AAO) is closely related withsummer rainfall in eastern China. When AAO is stronger inboreal spring, especially in May, there is more mei-yu rain-fall in summer with a longer period along the Yangtze andHuaihe River valley. In contrast, there is less rainfall with ashorter period corresponding to a weaker AAO. Besides, ananomalous AAO changes the position and intensity of severalcirculation systems, which are important to summer rainfallalong the Yangtze and Huaihe River valley. Furthermore, theAntarctic sea ice is negatively correlated with the intensity ofAAO with a 6-month leading time. The result in this studyprovides a new method for the prediction of mei-yu.展开更多
Relationship between the Antarctic oscillation (AAO) and the western North Pacific typhoon number (WNPTN) in the interannual variability is examined in this research. The WNPTN is correlated with the AAO in June-July-...Relationship between the Antarctic oscillation (AAO) and the western North Pacific typhoon number (WNPTN) in the interannual variability is examined in this research. The WNPTN is correlated with the AAO in June-July-August-September (JJAS) in 1949-1998 at -0.48 for the detrended time series, statistically significant at 99% level. The tropical atmospheric circulation as well as the sea surface temperature variability over the western Pacific associated with AAO has been analyzed. It follows that a positive phase of JJAS AAO corresponds to the larger magnitude of the vertical zonal wind shear, the anomalous low-lever anticyclonic circulation and anomalous high-level cyclonic circulation, and lower sea surface temperature in the major typhoon genesis region in the western North Pacific, thus providing unfavorable environment for the typhoon genesis, and vice versa.展开更多
The interannual variability of Antarctic Oscillation (AAO) and its influence on East Asian climate during both boreal winter and spring are addressed. The results show that the positive AAO anomaly decreases the cold ...The interannual variability of Antarctic Oscillation (AAO) and its influence on East Asian climate during both boreal winter and spring are addressed. The results show that the positive AAO anomaly decreases the cold activity over East Asia during both boreal winter and spring. AAO-related barotropic meridional teleconnection from Antarctic to Arctic is found through analysis of mean me- ridional circulations. This meridional teleconnection is remarkable over Eurasia during boreal winter and over the Pacific Ocean during boreal spring. The results also show that zonal mean zonal wind at high latitudes in Southern Hemisphere has well positive correlation with that of Eurasia during boreal winter and has negative correlation with Pacific North American teleconnection (PNA) during boreal spring, which again display the meridional teleconnection. Thus, local meridional teleconnection is a possible linkage for interaction of circulations at mid-high latitudes between both hemispheres.展开更多
Based on the NCEP/NCAR reanalysis data set, empirical orthogonal function analysis and correlation analysis have been carried out. Antarctic oscillation index (AOI) is defined as the difference between the zonal-mean ...Based on the NCEP/NCAR reanalysis data set, empirical orthogonal function analysis and correlation analysis have been carried out. Antarctic oscillation index (AOI) is defined as the difference between the zonal-mean monthly sea level pressure departures of 40°S and 65°S. Regional surface temperature and precipitation over the extratropical Southern Hemisphere have a close relationship with AOI.展开更多
In this study, we investigated the features of Arctic Oscillation （AO） and Antarctic Oscillation （AAO）, that is, the annular modes in the extratropics, in the internal atmospheric variability attained through an e...In this study, we investigated the features of Arctic Oscillation （AO） and Antarctic Oscillation （AAO）, that is, the annular modes in the extratropics, in the internal atmospheric variability attained through an ensemble of integrations by an atmospheric general circulation model （AGCM） forced with the global observed SSTs. We focused on the interannual variability of AO/AAO, which is dominated by internal atmospheric variability. In comparison with previous observed results, the AO/AAO in internal atmospheric variability bear some similar characteristics, but exhibit a much clearer spatial structure： significant correlation between the North Pacific and North Atlantic centers of action, much stronger and more significant associated precipitation anomalies, and the meridional displacement of upper-tropospheric westerly jet streams in the Northern/Southern Hemisphere. In addition, we examined the relationship between the North Atlantic Oscillation （NAO）/AO and East Asian winter monsoon （EAWM）. It has been shown that in the internal atmospheric variability, the EAWM variation is significantly related to the NAO through upper-tropospheric atmospheric teleconnection patterns.展开更多
This study examined the relationship between the boreal spring(April?May) Antarctic Oscillation(AAO) and the North American summer monsoon(NASM)(July?September) for the period of 1979?2008.The results show that these ...This study examined the relationship between the boreal spring(April?May) Antarctic Oscillation(AAO) and the North American summer monsoon(NASM)(July?September) for the period of 1979?2008.The results show that these two systems are closely related.When the spring AAO was stronger than normal,the NASM tended to be weaker,and there was less rainfall over the monsoon region.The opposite NASM situation corresponded to a weaker spring AAO.Further analysis explored the possible mechanism for the delayed impact of the boreal spring AAO on the NASM.It was found that the tropical Atlantic sea surface temperature(SST) plays an important role in the connection between the two phenomena.The variability of the boreal spring AAO can produce anomalous SSTs over the tropical Atlantic.These SST anomalies can persist from spring to summer and can influence the Bermuda High,affecting water vapor transportation to the monsoon region.Through these processes,the boreal spring AAO exerts a significantly delayed impact on the amount of NASM precipitation.Thus,information about the boreal spring AAO is valuable for the prediction of the NASM.展开更多
文摘Both correlation analysis and case study indi-cate that Antarctic oscillation (AAO) is closely related withsummer rainfall in eastern China. When AAO is stronger inboreal spring, especially in May, there is more mei-yu rain-fall in summer with a longer period along the Yangtze andHuaihe River valley. In contrast, there is less rainfall with ashorter period corresponding to a weaker AAO. Besides, ananomalous AAO changes the position and intensity of severalcirculation systems, which are important to summer rainfallalong the Yangtze and Huaihe River valley. Furthermore, theAntarctic sea ice is negatively correlated with the intensity ofAAO with a 6-month leading time. The result in this studyprovides a new method for the prediction of mei-yu.
基金Supported by the National Natural Science Foundation of China (Grant Nos. 40631005 and 40620130113)CAS International Partnership Project
文摘Relationship between the Antarctic oscillation (AAO) and the western North Pacific typhoon number (WNPTN) in the interannual variability is examined in this research. The WNPTN is correlated with the AAO in June-July-August-September (JJAS) in 1949-1998 at -0.48 for the detrended time series, statistically significant at 99% level. The tropical atmospheric circulation as well as the sea surface temperature variability over the western Pacific associated with AAO has been analyzed. It follows that a positive phase of JJAS AAO corresponds to the larger magnitude of the vertical zonal wind shear, the anomalous low-lever anticyclonic circulation and anomalous high-level cyclonic circulation, and lower sea surface temperature in the major typhoon genesis region in the western North Pacific, thus providing unfavorable environment for the typhoon genesis, and vice versa.
基金supported by the Key Program of the Chinese Academy of Sciences(Grant No.KZCX3-SW-221)the National Natural Science Foundation of China(Grant Nos.40125014 and 40475037).
文摘The interannual variability of Antarctic Oscillation (AAO) and its influence on East Asian climate during both boreal winter and spring are addressed. The results show that the positive AAO anomaly decreases the cold activity over East Asia during both boreal winter and spring. AAO-related barotropic meridional teleconnection from Antarctic to Arctic is found through analysis of mean me- ridional circulations. This meridional teleconnection is remarkable over Eurasia during boreal winter and over the Pacific Ocean during boreal spring. The results also show that zonal mean zonal wind at high latitudes in Southern Hemisphere has well positive correlation with that of Eurasia during boreal winter and has negative correlation with Pacific North American teleconnection (PNA) during boreal spring, which again display the meridional teleconnection. Thus, local meridional teleconnection is a possible linkage for interaction of circulations at mid-high latitudes between both hemispheres.
文摘Based on the NCEP/NCAR reanalysis data set, empirical orthogonal function analysis and correlation analysis have been carried out. Antarctic oscillation index (AOI) is defined as the difference between the zonal-mean monthly sea level pressure departures of 40°S and 65°S. Regional surface temperature and precipitation over the extratropical Southern Hemisphere have a close relationship with AOI.
基金This work is supported by the National Natural Science Foundation of China(Grant Nos.40475025 and 40221503)Buwen Dong was supported by the ENSEMBLES Project(GOCE-CT-2003-505539)at the UK Natural Environmental Research Council Centres for Atmospheric Science.
文摘In this study, we investigated the features of Arctic Oscillation （AO） and Antarctic Oscillation （AAO）, that is, the annular modes in the extratropics, in the internal atmospheric variability attained through an ensemble of integrations by an atmospheric general circulation model （AGCM） forced with the global observed SSTs. We focused on the interannual variability of AO/AAO, which is dominated by internal atmospheric variability. In comparison with previous observed results, the AO/AAO in internal atmospheric variability bear some similar characteristics, but exhibit a much clearer spatial structure： significant correlation between the North Pacific and North Atlantic centers of action, much stronger and more significant associated precipitation anomalies, and the meridional displacement of upper-tropospheric westerly jet streams in the Northern/Southern Hemisphere. In addition, we examined the relationship between the North Atlantic Oscillation （NAO）/AO and East Asian winter monsoon （EAWM）. It has been shown that in the internal atmospheric variability, the EAWM variation is significantly related to the NAO through upper-tropospheric atmospheric teleconnection patterns.
基金supported by the Key Program of theChinese Academy of Sciences (Grant No. KZCX2-YW-Q03-3)the Special Scientific Research Fund of Meteorological Public Welfare Profession of China (Grant No. GYHY200906018)the Na- tional Basic Research Program of China (Grant No. 2009CB421406)
文摘This study examined the relationship between the boreal spring(April?May) Antarctic Oscillation(AAO) and the North American summer monsoon(NASM)(July?September) for the period of 1979?2008.The results show that these two systems are closely related.When the spring AAO was stronger than normal,the NASM tended to be weaker,and there was less rainfall over the monsoon region.The opposite NASM situation corresponded to a weaker spring AAO.Further analysis explored the possible mechanism for the delayed impact of the boreal spring AAO on the NASM.It was found that the tropical Atlantic sea surface temperature(SST) plays an important role in the connection between the two phenomena.The variability of the boreal spring AAO can produce anomalous SSTs over the tropical Atlantic.These SST anomalies can persist from spring to summer and can influence the Bermuda High,affecting water vapor transportation to the monsoon region.Through these processes,the boreal spring AAO exerts a significantly delayed impact on the amount of NASM precipitation.Thus,information about the boreal spring AAO is valuable for the prediction of the NASM.
