Relationships between summer rainfall over China and ocean temperatures in the tropical western Pacific

Aspects of the associations between summer (June-August) rainfall over China and ocean temperatures in the 'warm pool' region in the tropical western Pacific have been examined. This has been achieved with precipitation records for 160 stations and sea surface temperature data from the GOADS covering the 40-year period 1951-90. The spatial distribution of the rainfall-SST correlations were found to vary considerably according to location of the SST target area. There were significant positive associations between the interannual variation of summer rainfall in the lower part of the Yangtze River valley and SST in the 10-20 degrees N, 120-130 degrees E Marsden square. To the north: over the Huaihe River valley, the correlations assumed opposite signs. When the SST over the Marsden square to the southeast (i.e., 0-10 degrees N, 130-140 degrees E) was considered, the correlations became very small and were not significant. For the period considered here, there appears to be little synchronous connection between the Southern Oscillation Index and summer station precipitation in China. Our results differ from those that have been obtained with data periods shorter than we use here. The findings suggest that the nature of the association between summer rainfall and 'warm pool' temperatures exhibit multi-decadal variability and, in particular, underwent a change in about 1970.