摘要
Using the in-situ precipitation and NCEP/NCAR daily reanalysis data, we foundby studies of change of moisture flux and its effect that the northward water vapor transportrepresented by moisture flux in East China tends to retreat southward, and the eastward water vaportransport tends to weaken with weakening of the intensity of moisture flux. The north boundary ofmeridional moisture flux (50 kg m^(-1)s^(-1)) retreats 2.8 degrees in latitude per decade during1968-2003. The weakening of water vapor transport implies the weakening and southward retreat ofEast Asian monsoon, which leads to the tendency of decrease in moisture flux convergence over NorthChina and the middle and lower reaches of the Yellow River, and the tendency of decrease inprecipitation over those regions, but on the contrary the enhanced water vapor transport convergenceover the middle and lower reaches of the Yangtze River implies the tendency of increase inprecipitation to some extent. Indeed the long-term variability of precipitation in East China has aclose relation with that of atmospheric moisture flux.
Using the in-situ precipitation and NCEP/NCAR daily reanalysis data, we foundby studies of change of moisture flux and its effect that the northward water vapor transportrepresented by moisture flux in East China tends to retreat southward, and the eastward water vaportransport tends to weaken with weakening of the intensity of moisture flux. The north boundary ofmeridional moisture flux (50 kg m^(-1)s^(-1)) retreats 2.8 degrees in latitude per decade during1968-2003. The weakening of water vapor transport implies the weakening and southward retreat ofEast Asian monsoon, which leads to the tendency of decrease in moisture flux convergence over NorthChina and the middle and lower reaches of the Yellow River, and the tendency of decrease inprecipitation over those regions, but on the contrary the enhanced water vapor transport convergenceover the middle and lower reaches of the Yangtze River implies the tendency of increase inprecipitation to some extent. Indeed the long-term variability of precipitation in East China has aclose relation with that of atmospheric moisture flux.
基金
Supported by the National Natural Science Foundation of China under Grant No. 40575038.
