Association of the Rainy Season Precipitation with Low-Level Meridional Wind in the Yangtze River Valley and North China

Abstract

his study first used measurements to establish the association between the rainy season precipitation in the Yangtze River valley (YRV) and north China (NC) and the 850-hPa meridional wind, and then evaluated the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4) models? simulations of both the associations and precipitation amount. It is shown that there exists a statistically significant positive correlation in the June?July precipitation and wind gradient over the YRV, and in the July?August precipitation and wind over NC. These associations are robust at daily, monthly, and interannual scales. Although many models are found to be capable of simulating the associations, the precipitation amount is still quite inadequate when compared with observations, thus raising the issue of the importance of lower-level wind simulations.