Studies Of Forecasting Methods On The Summer Drought And Flood As Well As Phased Drought In Chifeng Area Of Inner Mongolia Autonomous Region

Researches on the evolution characteristics of summer precipitation, the developing characteristics and circulation pattern of summer drought and flood(SDF) and phased drought as well as the effects of climate warming on the SDF have been made by using the data of precipitation and temperature from ten weather stations in Chifeng area of Inner Mongolia Autonomous Region, the synoptic charts and other products disseminated by National Climate Center. The emphases were put on the main elements that were affected the summer precipitation, especially the SDF, such as factors of climate, sunspot and atmosphere general circulation. The relations between Mongolia cold vortex, sub-tropical high, mid-latitude circulation and SDF were studied in the atmosphere general circulation part. Selected elements integrated through different contributions and influence types were used to form a SDF prediction model in order to improve such extreme climate events prediction of SDF. The integrated multi-indices method was used in the prediction of phased drought, it predicted monthly rainfall in summer and then determined phased drought type by taking into account the summer total rainfall prediction.The researched results show that the summer precipitation cycle exists in Chifeng area, there are 4 distinct dry and wet phases.The climate factors affecting on the SDF are as follows: The first, the cycle of flood are different. The cycle of flood years is 10 years during the dry phase of summer precipitation, on the contrary, the cycle is 5 years. The second, the low-grade drought and drought years often occurred during the dry phase of summer precipitation, the frequency is about 90.9%, thereinto drought years the frequency was about 70.0%. For drought years, but less than 10% for the flood years, on the contrary, flood years often occurred during the wet phase, the frequency is about 25% for the flood years, but less than 27% for the drought years. The third, SDF alternate, and that the flood years are series and the drought years are not.