The Study Of Climate And Forecast Of High-temperature And Summer Drought In Chongqing Province

The data of this article are the surface weather data of 34 meteorological observation stations in Chongqing province and the NCEP reanalysis data.By using the M-K change analysis, EOF decompound and morlet wavelet methods etc,the spatial and temporal features, circulation characters of high temperature and summer drought are studied. Lastly with the temperature variation method and BP neural network method, the forecast of the high temperature and the summer drought means are studied. Then we get the results.The place of the surface especially high temperature of Chongqing is in Qijiang, Wanshen, Banan, Jiangjin, which are located in the south-west of Chongiqng, and the place of the minimum value surface high temperature of Chongqing is in Youyang which is located in the south-east of Chongiqng.The temperature are 44℃and 38.1℃respectively.There is a close relation between the surface temperature and sky temperature in Chongqing, and the strength of the relation decreases with the altitude increasing. There is a trend of decreasing-increasing in the surface and sky temperature, but the change year is not obvious. There is an evolutional trend of increasing with the surface and sky temperature from 1990s, and the trend in the sky is earlier than on the ground.There are four regions with more high temperature days in Chongqing. The largest value of general, serious and special serious high temperature days is 21d/a,14d/a and 2d/a respectively. The high temperature day occurs mainly in July and August, and there are much more high temperature days in August than in July. In last 50 years, the high temperature days have an evolutional trend of increasing-decreasing-increasing and the variation tendency is especially obvious about serious high temperature days.There is a high prevalence area of summer drought in Fulin, Fengdu and Jiangjin, and a low prevalence area in Wanshen, Chenkou. The most of summer drought start time is early July, and there are 56.6% summer drought start time in July. The trend of summer drought is increasing-decreasing-steady from 1970s to 1990s in Chongqing, but there are more serious and especially serious summer drought from 1990s. The change time of summer drought is 1979 in Chongqing. The summer drought decreasing of Yubei and Wusan are very fast from 1970s to 1980s, and the summer drought increasing of Yubei, Tongliang, Wushan are extremely fast from 1980s to 1990s.The trend of Chenkou summer drought is increasing-decreasing, and the trend is different from the other place of Chongqing.The high temperature and summer drought indexes are defined by using meteorological elements. The high temperature and summer drought prediction model based on BP neural network is es tablished too. The results show that the variations of high temperature and summer drought in Chongqing contain obvious periodic features. The model is a superior an d useful method for the actual operational forecasting.