THE EFFECTS OF SEA SURFACE TEMPERATURE OVER THE EQUATORIAL WESTERN PACIFIC AND THE INDIAN OCEAN ON THE ASIAN SUMMER MONSOON

In this paper, the p-σ five layer primitive equation model segmented by mountains and physicalparameterizations including short wave radiation; long wave radiation; large-scale and convective condensation;heat and moisture transport from surface to the first model level is used. The horizonial resolution is 5°lat. ×5° long. with the integration region from 25°S to 55°N and from 5°W eastward to 175°W. Themodel was spun up with perpetual June boundary conditions and forcing starting with June zonal meanheights and geostrophic wind field. In order to investigate the effects of SST (sea surface tempefuture) over the equatorial Western Pacificand the Indian Ocean on the Asian summer monsoon, four sets of numerical experments with positiveanomalies over the equatorial Western Pacific, and positive and negative anomalies over the Western IndianOcean, and zonal mean SST (the control case) are performed. The experimental results show that theSouth Asian low in the lower troposphere and the anticyclone over the South Asia in the uppet troposphereintensified when positive SST anomalies over the equatorial Western Pacific is included. A statistical testmethod for simulations is proposed. Finally, the influence mechanism of the SST anomalies over the equatorial oceans is discussed. It isworth stressing that the effects of the SST over the equatorial oceans on the Asian summer monsoon canarise as a result of interaction of SST anomalies, atmospheric flow field and heat sources and sinks in theatmosphere.