CHARACTERISTICS OF PRECIPITATION AND WATER VAPOR TRANSPORT DURING SPRINGTIME IN THE EASTERN NORTHWEST CHINA

The basic anomalous charact eristics of the precipitation and water vapor transport during springtime in the eastern Northwest China (ENWC) were investigated by using daily precipitation data from NMC and NCEP/NCAR reanalysis data from 1962 to 2002. The analysed results show that, with the significant interannual and interdecadal variability features, the spring time precipitation in ENWC is comparatively concentrative and the water vapor is mostly from the southern monsoon region via three basic approaches including the Qinghai-Tibet Plateau, south, and east directions. Also, the anomalous water vapor is recognized by the west ward transportation from eastern sea area, and the previous northward transport from the Philippines and its neighboring ocean. Furthermore, through decomposition of anomalous water vapor transport find that the averaged water vapor transport induced by general circulation anomaly plays an leading role in most positive precipitation anomaly years and the anomalous water vapor transported previously by the basic general circulation is important to local rainfall. The farther analysis shows that a positive anomaly center of general circulation in height fieldlying in the region of Northeast China helps to the east erly and southerly water vapor transport anomalies in rainy years. At the Rametiine, its also found that air water resource in ENWC has certain petential of compensation and utility, and ENWC is a key region of water vapor transport which keeps air water resource and water cycle process in Northwest China.