Based on the historical and RCP8.5 runs of the multi-model ensemble of 32 models participating in CMIP5, the present study evaluates the formation mechanisms for the patterns of changes in equatorial Pacific SST under...Based on the historical and RCP8.5 runs of the multi-model ensemble of 32 models participating in CMIP5, the present study evaluates the formation mechanisms for the patterns of changes in equatorial Pacific SST under global warming. Two features with complex formation processes, the zonal E1 Nifio-like pattern and the meridional equatorial peak warm- ing （EPW）, are investigated. The climatological evaporation is the main contributor to the E1 Nifio-like pattern, while the ocean dynamical thermostat effect plays a comparable negative role. The cloud-shortwave-radiation-SST feedback and the weakened Walker circulation play a small positive role in the E1 Nifio-like pattern. The processes associated with ocean dynamics are confined to the equator. The climatological evaporation is also the dominant contributor to the EPW pattern, as suggested in previous studies. However, the effects of some processes are inconsistent with previous studies. For example, changes in the zonal heat advection due to the weakened Walker circulation have a remarkable positive contribution to the EPW pattern, and changes in the shortwave radiation play a negative role in the EPW pattern.展开更多
This paper analyzes the differences in the characteristics and spatio–temporal variabilities of summertime rainfall and water vapor transport between the East Asian summer monsoon（EASM） and South Asian summer mons...This paper analyzes the differences in the characteristics and spatio–temporal variabilities of summertime rainfall and water vapor transport between the East Asian summer monsoon（EASM） and South Asian summer monsoon（SASM） systems. The results show obvious differences in summertime rainfall characteristics between these two monsoon systems. The summertime rainfall cloud systems of the EASM show a mixed stratiform and cumulus cloud system, while cumulus cloud dominates the SASM. These differences may be caused by differences in the vertical shear of zonal and meridional circulations and the convergence of water vapor transport fluxes. Moreover, the leading modes of the two systems＇ summertime rainfall anomalies also differ in terms of their spatiotemporal features on the interannual and interdecadal timescales. Nevertheless, several close links with respect to the spatiotemporal variabilities of summertime rainfall and water vapor transport exist between the two monsoon systems. The first modes of summertime rainfall in the SASM and EASM regions reveal a significant negative correlation on the interannual and the interdecadal timescales. This close relationship may be linked by a meridional teleconnection in the regressed summertime rainfall anomalies from India to North China through the southeastern part over the Tibetan Plateau, which we refer to as the South Asia/East Asia teleconnection pattern of Asian summer monsoon rainfall. The authors wish to dedicate this paper to Prof. Duzheng YE, and commemorate his 100 thanniversary and his great contributions to the development of atmospheric dynamics.展开更多
Variations of winter Arctic sea ice bordering on the North Atlantic are closely related to climate variations in the same region. When winter North Atlantic Oscillation (NAO) index is positive (negative) anomaly phase...Variations of winter Arctic sea ice bordering on the North Atlantic are closely related to climate variations in the same region. When winter North Atlantic Oscillation (NAO) index is positive (negative) anomaly phase, Icelandic Low is obviously deepened and shifts northwards (southwards). Simultaneously, the Subtropical High over the North Atlantic is also intensified, and moves northwards (southwards). Those anomalies strengthen (weaken) westerly between Icelandic Low and the Subtropical High, and further result in positive (negative) sea surface temperature (SST) anomalies in the mid-latitude of the North Atlantic, and increase (decrease) the warm water transportation from the mid-latitude to the Barents Sea, which causes positive (negative) mixed-layer water temperature anomalies in the south part of the Barents Sea. Moreover, the distribution of anomaly air temperature clearly demonstrates warming (cooling) in northern Europe and the subarctic regions (including the Barents Sea) and cooling展开更多
By means of monthly mean NCEP/NCAR data analyses, this note investigates the lag influences of winter circulation conditions in the tropical western Pacific on South Asian summer monsoon through the methods of composi...By means of monthly mean NCEP/NCAR data analyses, this note investigates the lag influences of winter circulation conditions in the tropical western Pacific on South Asian summer monsoon through the methods of composite, correlation and statistical confident test. The results indicate clearly that winter climate variations in the equatorial western Pacific would produce significant influences on the following South Asian summer monsoon, and with the lapse of time the lag influences show clearly moving northward and extending westward features. When winter positive (negative) sea level pressure anomalies occupy the equatorial western Pacific, there is an anticyclonic (cyclonic) circulation anomaly appearing in the northwestern Pacific. With the lapse of time, the anticyclonic (cyclonic) circulation anomaly gradually moves to northeast, and its axis in the west-east directions also stretches, therefore, easterly (westerly) anomalies in the south part of the anticyclonic (cyclonic) circulation anomaly展开更多
Over the past few decades,extreme tropical cyclone(TC)events have become more common.During the 2019 typhoon season in the western North Pacific(WNP),7 super typhoons hit East Asia.Super Typhoon Lekima(2019)caused eco...Over the past few decades,extreme tropical cyclone(TC)events have become more common.During the 2019 typhoon season in the western North Pacific(WNP),7 super typhoons hit East Asia.Super Typhoon Lekima(2019)caused economic loss of at least RMB 51.53 billion yuans and 56 fatalities in the China's Mainland.展开更多
基金supported by the National Basic Research Program of China (Grant Nos. 2014CB953903 and 2012CB955604)the National Natural Science Foundation of China (Grant Nos. 41575088 and 41461164005)
文摘Based on the historical and RCP8.5 runs of the multi-model ensemble of 32 models participating in CMIP5, the present study evaluates the formation mechanisms for the patterns of changes in equatorial Pacific SST under global warming. Two features with complex formation processes, the zonal E1 Nifio-like pattern and the meridional equatorial peak warm- ing （EPW）, are investigated. The climatological evaporation is the main contributor to the E1 Nifio-like pattern, while the ocean dynamical thermostat effect plays a comparable negative role. The cloud-shortwave-radiation-SST feedback and the weakened Walker circulation play a small positive role in the E1 Nifio-like pattern. The processes associated with ocean dynamics are confined to the equator. The climatological evaporation is also the dominant contributor to the EPW pattern, as suggested in previous studies. However, the effects of some processes are inconsistent with previous studies. For example, changes in the zonal heat advection due to the weakened Walker circulation have a remarkable positive contribution to the EPW pattern, and changes in the shortwave radiation play a negative role in the EPW pattern.
基金supported jointly by the National Key Research and Development Program(Grant No.2016YFA0600603)the National Basic Research of China(Grant No.2013CB430201)the National Natural Science Foundation of China(Grant Nos.41605058,41375065,41461164005,41230527,and 41375082)
文摘This paper analyzes the differences in the characteristics and spatio–temporal variabilities of summertime rainfall and water vapor transport between the East Asian summer monsoon（EASM） and South Asian summer monsoon（SASM） systems. The results show obvious differences in summertime rainfall characteristics between these two monsoon systems. The summertime rainfall cloud systems of the EASM show a mixed stratiform and cumulus cloud system, while cumulus cloud dominates the SASM. These differences may be caused by differences in the vertical shear of zonal and meridional circulations and the convergence of water vapor transport fluxes. Moreover, the leading modes of the two systems＇ summertime rainfall anomalies also differ in terms of their spatiotemporal features on the interannual and interdecadal timescales. Nevertheless, several close links with respect to the spatiotemporal variabilities of summertime rainfall and water vapor transport exist between the two monsoon systems. The first modes of summertime rainfall in the SASM and EASM regions reveal a significant negative correlation on the interannual and the interdecadal timescales. This close relationship may be linked by a meridional teleconnection in the regressed summertime rainfall anomalies from India to North China through the southeastern part over the Tibetan Plateau, which we refer to as the South Asia/East Asia teleconnection pattern of Asian summer monsoon rainfall. The authors wish to dedicate this paper to Prof. Duzheng YE, and commemorate his 100 thanniversary and his great contributions to the development of atmospheric dynamics.
基金the National Natural Science Foundation of China (Grant No. 49905003).
文摘Variations of winter Arctic sea ice bordering on the North Atlantic are closely related to climate variations in the same region. When winter North Atlantic Oscillation (NAO) index is positive (negative) anomaly phase, Icelandic Low is obviously deepened and shifts northwards (southwards). Simultaneously, the Subtropical High over the North Atlantic is also intensified, and moves northwards (southwards). Those anomalies strengthen (weaken) westerly between Icelandic Low and the Subtropical High, and further result in positive (negative) sea surface temperature (SST) anomalies in the mid-latitude of the North Atlantic, and increase (decrease) the warm water transportation from the mid-latitude to the Barents Sea, which causes positive (negative) mixed-layer water temperature anomalies in the south part of the Barents Sea. Moreover, the distribution of anomaly air temperature clearly demonstrates warming (cooling) in northern Europe and the subarctic regions (including the Barents Sea) and cooling
基金This work was supported by the National Key Basic Research Program (Grant No. G1998040900).
文摘By means of monthly mean NCEP/NCAR data analyses, this note investigates the lag influences of winter circulation conditions in the tropical western Pacific on South Asian summer monsoon through the methods of composite, correlation and statistical confident test. The results indicate clearly that winter climate variations in the equatorial western Pacific would produce significant influences on the following South Asian summer monsoon, and with the lapse of time the lag influences show clearly moving northward and extending westward features. When winter positive (negative) sea level pressure anomalies occupy the equatorial western Pacific, there is an anticyclonic (cyclonic) circulation anomaly appearing in the northwestern Pacific. With the lapse of time, the anticyclonic (cyclonic) circulation anomaly gradually moves to northeast, and its axis in the west-east directions also stretches, therefore, easterly (westerly) anomalies in the south part of the anticyclonic (cyclonic) circulation anomaly
基金supported by the National Natural Science Foundation of China (Grant No. 41875117)the Youth Innovation Promotion Association CAS (Grant No. 2017106)
文摘Over the past few decades,extreme tropical cyclone(TC)events have become more common.During the 2019 typhoon season in the western North Pacific(WNP),7 super typhoons hit East Asia.Super Typhoon Lekima(2019)caused economic loss of at least RMB 51.53 billion yuans and 56 fatalities in the China's Mainland.
