孟加拉湾深对流加热对东亚季风环流系统的影响

利用40年逐日NCEP/NCAR再分析资料、ReynoldsSST资料和R42L9GOALS模式,研究孟加拉湾深对流加热对东亚副热带季风环流系统的影响及其与ENSO的关系。结果表明:孟加拉湾东岸季风于26候开始爆发,其深对流加热的旋转经验正交函数(REOF)分析表明,其激发的东传Rossby波在中高纬度地区具有相当正压结构。数值试验证实孟加拉湾降水增多,其东侧南海到长江以南区域降水明显减少。分析发现季风环流强度指数极小值和Walker环流强度指数极大值的出现对SSTA转折均具超前性,因此,季风环流的变化对预报ElNino减弱或LaNina结束及SSTA变化趋势具有一定的指示意义。

EFFECT OF BOB DEEP CONVECTION HEATING ON EAST ASIAN MONSOON CIRCULATION

In terms of NCEP/NCAR daily reanalysis data sets, outgoing long-wave radiation (OLR) data, Reynold SST data and the R42L9 GOALS model, The effect of Bay of Ben gal (BOB) deep convection heating with East Asian monsoon circulation and the re lationship with ENSO were analyzed. Results show that east coast of BOB is the earliest onset region of Asian summer monsoon in the 26th pentad, the deep convec tion activity may be possible key tache between South Asian monsoon and East Asi an monsoon. REOF of BOB heating depicts that the excitated Rossby wave transmits eastward along with mid-high latitude, conducing the increase of anti-cyclone circulation over East Asian subtropical region. Numerical experiments validate that the precipitation should be decreased between South China sea and low-midd le reaches of Yangtze river while the BOB deep convection heating decreasing. Monsoon circulation index and Walker circulation index have good relationship with El Ni o weaken and La Nina ended in respectively.