East Asian Summer Monsoon And Drought In Northwest China Relations Analysis

Using monthly mean rainfall and temperature data in North-west of China (NWC), the characteristics of rainfall anomaly at rainy season in NWC and the inter-annual varieties of drought/flood are diagnosed by means of EOF, REOF and wavelet analysis et al. And the NCEP/NCAR monthly reanalyzed data are employed to analyse the evolution character of water vapor flux and it's divergence flux, 500hPa height and u, v wind field. Results show that (a) The space distribution of rainfall anomaly can be separated into seven climate sensitive areas, the first and the third region have the same rought/flood trend . (b) The precipitation is effected by the East Asian summer monsoon on regions of east of 100?E. (c) Vapour flux is transported from west and southwest forward.(d) In the weak monsoon year, NWC lies in the northwest airflow region, west and south wind, as well as moisture transportation are remarkably reduced.except part of the first field ,there is vapour flux divergenceon in NWC(e) In the strong monsoon years, the height field is low on the west and high on the east, west and south wind, and it's vapor flux transportation, are evidently boosted up.There is vapour flux conflurnce in the he first and sixth region.