Abstract:In this paper, a northern-ward neutercance (8509) in its developing process was analysed using the full ω-equation. The result was compared with another typhoon (8406) whose early path and intensity were similar with 8509. The results show. (1) In the stage of tropical cyclone, the cumulus convective heating and large-scale latent heating are the main factors to maintain its vertical motion. (2) Temperature advection is the main cause and prior-condition to the reutercance. (3) cumulus convective heating also makes its important contribution to the reuter-cence, and has evident suppliment and strengthening effectness to the precipitation of typhoon rain area.

Abstract:Two precipitation processes, occured on 25 May and 12 May 1987 respectively in Wuhan area, were analysed quantitatively by means of variation and average adjustment technique using digital radar echo and rainfall data collected with auto-raingagues.The results have shown that the average adjustment technique, would reduce errors of radar measurement, but the peak values of precipitation were smoothed out. The variation technique is used to fit the distribution measured by radar into that by .auto-raingagues but keep the precipitation detected by radar in. its original pattern. The relative error is less than 10%.

Abstract:In this paper, some abrupt changes of the air temperature and precipitation from 1873 to 1989 in Shanghai and Beijing have been tested using Mann-Kendall method. It is showed that the temperature series in Shanghai and Beijing contained abrupt changes from cool to warm in 1932 and 1919, respectively. Meanwhile, it is found that the abrupt change of precipitation in Shanghai occurred in 1906, hereafter the precipitation become more. The abrupt change of precipitation in Beijing occurred in 1903 which was a turn from wet to dry. In addition, other methods have also been used to vertify the points of abrupt changes.

Abstract:When a tropical cyclone enters the prognostic range, the lastest 6 samples similar with it will be picked up from 150 historical ones and the relative precipitation processes will be weighted according to their tracks respectively, thus, getting the expected value as the forecast value for the total precipitation of the newly coming tropical cyclone. Man-computer interactive method is adopted through the course and the equipluves chart of the total precipitation over Zhejiang Province is produced finally.