The splitting of the Northern Hemisphere sub-tropical high (SH) during spring to summer and its possible mechanisms has been analyzed. Results indicate that the splitting of SH occurs over the Bay of Bengal to the Ind...The splitting of the Northern Hemisphere sub-tropical high (SH) during spring to summer and its possible mechanisms has been analyzed. Results indicate that the splitting of SH occurs over the Bay of Bengal to the Indo-China peninsula. However, remarkable contrast exists in the Hadley cell at the lower and upper levels over these sectors during March to May. The land surface sensitive/latent heating both play an important role, and decay the local Hadley cell over the Indo-China peninsula by enhancing the upwelling. In contrast, the dominant land surface sensitive heating over the Bay of Bengal only damages the low-level Hadley cell. Thus, the splitting of SH should occur over the Indo-China peninsula, rather than the Bay of Bengal at lower levels. In addition, the analysis suggests that the faster seasonal snow melting in the east of Indo-China peninsula can enhance the land surface sensitive heating atmosphere and weaken the local Hadley cell, such seasonal change benefits the splitting of the SH.展开更多
1 INTRODUCTIONAs confirmed by many studies, sea surface pressure is of interannual variations in subtropical Southern Hemisphere, which is defined as the Southern-hemisphere Annual Mode （SAM）. It is in fact a seesaw...1 INTRODUCTIONAs confirmed by many studies, sea surface pressure is of interannual variations in subtropical Southern Hemisphere, which is defined as the Southern-hemisphere Annual Mode （SAM）. It is in fact a seesaw effect of sea surface pressure symmetric longitudinally between the South Pole region and austral middle latitudes. SAM is in fact a correction to the Antarctic Atmospheric Oscillation （AAO）. At present, more attention is paid to the structure of SAM and its influence on the climate in mid- and higherlatitudes of SH than to the links between SAM and anomalies of boreal general circulation and climate. This work focuses on the relation among SAM in boreal spring （April - May）, Mei-yu （sustaining rains） in the middle and lower reaches of the Yangtze River and East Asian monsoon.展开更多
基金Project "863" (2002AA135360) Key Project from the National Natural Science Foundation ofChina (40135020)+2 种基金 National Natural Science Foundation of China (40375014) Funding Program for OutstandingYoung Teachers from the Ministry of Education Open Project from LASG of the Institute of AtmosphericPhysics of the Chinese Academy of Sciences
文摘The splitting of the Northern Hemisphere sub-tropical high (SH) during spring to summer and its possible mechanisms has been analyzed. Results indicate that the splitting of SH occurs over the Bay of Bengal to the Indo-China peninsula. However, remarkable contrast exists in the Hadley cell at the lower and upper levels over these sectors during March to May. The land surface sensitive/latent heating both play an important role, and decay the local Hadley cell over the Indo-China peninsula by enhancing the upwelling. In contrast, the dominant land surface sensitive heating over the Bay of Bengal only damages the low-level Hadley cell. Thus, the splitting of SH should occur over the Indo-China peninsula, rather than the Bay of Bengal at lower levels. In addition, the analysis suggests that the faster seasonal snow melting in the east of Indo-China peninsula can enhance the land surface sensitive heating atmosphere and weaken the local Hadley cell, such seasonal change benefits the splitting of the SH.
基金"Research on Subtropical Monsoon and Development of Relevant Forecasting Techniques"from Shanghai Meteorological Bureau
文摘1 INTRODUCTIONAs confirmed by many studies, sea surface pressure is of interannual variations in subtropical Southern Hemisphere, which is defined as the Southern-hemisphere Annual Mode （SAM）. It is in fact a seesaw effect of sea surface pressure symmetric longitudinally between the South Pole region and austral middle latitudes. SAM is in fact a correction to the Antarctic Atmospheric Oscillation （AAO）. At present, more attention is paid to the structure of SAM and its influence on the climate in mid- and higherlatitudes of SH than to the links between SAM and anomalies of boreal general circulation and climate. This work focuses on the relation among SAM in boreal spring （April - May）, Mei-yu （sustaining rains） in the middle and lower reaches of the Yangtze River and East Asian monsoon.
