Abstract:

The research on the heavy rainfall causing the flood Huaihe River basin during May to August in 2007 was focused on, using NCEP/NCAR reanalysis day-to-day data, the distribution and propagation features of multi-time scale precipitation over Huaihe River basin in the summer of 2007 were investigated. Morlet wavelet analysis results showed that there existed periodic change phenomenon of precipitation in quasi-35 days, quasi-18 days and quasi-8 days oscillaation. Periodic low frequency precipitation of quasi-35 days was from southwest propagation to the south of Huaihe River basin, and on the other hand from northwest propagation to the south central Huai River Basin; it was aslo clear that Nanhai was the propagation source of low frequency precipitation. The more short period of precipitation, the propagation features was not obvious. It was a very good corresponding relation that between horizontal divergence balance of from 200 hPa with 850 hPa and precipitation, horizontal divergence balance>0 corresponding to precipitation area, and horizontal divergence balance<0 to no precipitation area. The propagation of precipitation was mainly accord to horizontal divergence balance. The between horizontal divergence balance of from 200 hPa with 850 hPa was predictor of multi-time scale precipitation.