Zonal propagation of kinetic energy (KE) and convection in the South China Sea (SCS) and Indian summer monsoon areas are examined in present study. Results suggest that the SCS and Indian summer monsoon prevailed regions (5 —15°N) are dominated by the southwesterly wind, however, the disturbances of KE at 850 hPa and convection are observed mainly coming from the western Pacific Ocean (140—150°E), after passing through the SCS, and westward propagated into the Bay of Bengal (90—100°E). In the Indian summer monsoon domain, where the disturbances of KE are found mainly coming from the Arabian Sea (AS) and eastward propagated into the Bay of Bengal. Therefore, the SCS and the Indian summer mon- soon are quite different in zonal propagation of KE and convection. The SCS summer monsoon is mainly affected by the KE and convection coming from the tropical western Pacific. The Indian summer monsoon, however, can be partly influenced by the AS and the SCS summer monsoon. The analysis also suggests that the interaction region between the SCS and the Indian summer monsoon is around 90—95°E, rather than 105°E as proposed by earlier studies.
CHEN Longxun 1 ,GAO Hui 2 ,HE Jinhai 2 ,TAO Shiyan 3 & JIN Zuhui 3 1.Chinese Academy of Meteorological Sciences,Beijing 100081,China
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.
