The chosen factors in the temperature and precipitation equations established using HLAFS information in May to September are concluded in order to find out the factors used most frequently. Results show that factors chosen in the temperature forecasting equation for 24 hours are mainly before 24 hours，while in that for 48 hours，the factors are mainly after 24 hours，and the factors in real time are chosen in large probability，which is consistent with forecasterˊs；in precipitation forecasting equations，the first chosen factor is the divergence wind，and then the divergence and vorticity of Q vector. The heavy storm case in Qingyang on 4 July 1999 was used to analyze the real time and forecasting fields using most factors in forecasting equation，and the chosen factors have clear physical meaning，which provides reference basis for selecting precipitation factors in MOS forecast.

The support vector machine(SVM) is a new statistical study theory method which developed in recent years,  by using this method in
hail in the method is this paper',  We analyzed  the classific;ation prediction of hail weather based on summarizing the circulation(harac;teristic;s of hail in east region of Cansu provinc;e} and(ompared with traditional forecast under different weather types.It is confirmed that SVM method is not need to classify weather types and the effect of forecast model being established is better on many samples. This has provided new method and idea for hasin stations nn weather forecast.

Based on the data of 10℃initial dates and upper air temperature of 39 stations in Cansu loess plateau from 1971 to 2004 the(limatic; feature and(irc;ulation background of 10℃initial dates were analyzed in the paper  meanwhile the(limatic; prediction method  WHS  eSCabhShed f01' the I'epl'eSentatlVe  SCatlOn Of  Xlfeng.  1}eSn1tS  S1lOW  that thel'e  al'e 3 earlier and 3 later areas where the dally mean tempel'atm'e  SCeadlly  OVPI'  10℃，which are located in Beidao} Lanzhou} Jingc;huan} and Huajialing}  Dongxiang} Minxian} respec;trvely; and the earliest 10℃initial date is April 14 in Beidao} the latest date is June 5 in Huajialing; and 10℃initial date ocurged later in Dingxi and Lingxia, earlier in Tianshui} Pingliang} Qingyang and Baiyin.  The、hanging trend of the day when the mean temperature steadily over 10℃in Cansu loess parts of the region in 1980s it is earlier in the north plateau has been earlier and earlier since 1990s} and it is part and later in the south part. 500 hPa } 700 hPa height later f;ellls in 1970s in
are(ontrolled by the ridge of high pressure from the north part of Qinghai一Xizang plateau to Xinjiang} and temperature fields、ontrolled by the broad
temperature ridge there and OLR flow fields(ontrolled by positive anomalies on 10℃initial date in earlier years;  on the(ontrary, 500 hPa} 700 hPa height fields a1.e influenced by the deep trough over Tarim Basin temperature 10T:initial fields affected by the broad temperatune trough over Xinjiang} and OLR flow fields influenced by negative anomalies on late in later years

Based on an analysis of ecoclimatic applicability for millet, the climatic yield model was established in different climatic re-
gion. The key meteorological factors affecting yield were confirmed,which included≥10℃accumulated temperature, average temper-
ature from Aug to Sep, precipitation in July, altitude, the rate between investment and yield and so on.An integrated index system of
suitable planting division was given,and the eco-climatic planting division was divided into 5 grades.At the same time,the way to
enhance utilizing efficiency of ecoclimate resources was brought forward.

The drought index is defined by precipitation and evaporation in Longdong region during July and August in this paper，and it is used to denote drought.The drought climate feature is discussed by analyzing its precipitation and the drought index of 15 stations，and it is found 500 hPa mean situation is different in drought and rain yyear.The cause of drought is also discussed by the correlation between drought and Pacific temperature and 500hPa height feild，and finally the forecast model has been established

Based on analysis of phenological features and metorological conditions during the growing period of prosomillet in Gansu province，the main agrometeorological facts that influence on the growth of prosomillet have been found out and discussed.The influences of meterological factors on the yield of prosomillet has been analyzed with statistical methods.The complex in dices system of ecoclimate regionalzation for planting prosomillet in Gansu province has been given，and the suitable regions have been pointed out，the fit
and unfit conditions in different regions have been commented.

It has very intensive particularity in climate simulation on arid area. Climate numerical models are useful means and tools for study the physical mechanism of arid area' s form. Developments on arid climate numerical simulations and experiments were introduced in this paper ,and surface albedo ,soil humidity and parameters of vegetation and their effects on climate were summarized. We also discussed the significance of land一surface process on climate simulation. And then we reviewed numerical studies on climate and weather disasters in arid area. Finally ,it was pointed out that thoroughly studies on land一surface process in arid area and demarcate for parameters of land surface is an important approach to improve numerical simulation in arid area.