Based on precipitation from 280 meterological stations in west China and NCEP reanalysis data of OLR，the relationship between autumn precipitation anomaly and OLR in western China was analyzed using EOF，correlation analysis method．The main results are as follows:(1)The high value area of autumn OLR corresponded to the low value area of autumn precipitation，and the autumn OLR and precipitation had the remarkable opposite tendency，which indicated the increase((reduction)of autumn OLR would cause the reduction(increase)of autumn precipitation;(2)There was a large remarkable inverse correlative region between autumn OLR and precipitation in west China，especially in northwest and southeast area of west China，and in September inverse correlative area was biggest;(3)By the EOF analysis，the autumn OLR was most sensitive in the southern Xinjiang basin and northeast of Qinghai plateau，in Septemper the abnormal increase(decrease)of the autumn OLR in Turpan of Xingjiang，the autumn precipitation in southwest Xinjiang，north region of Qinghai plateau，Gannan plateau and middle Gansu was more(few)，but in the Tibet and western Sichuan plateau was few(more);In October the autumn OLR’s abnormity in west Inner Mongolia Xinjiang would resulted in remarkable inverse change of autumn precipitation in Xinjiang，north Shaanxi，north Sichuan and west Guangxi;In November the autumn OLR’s abnormity in Taklimakan desert would resulted in remarkable oppositive change of autumn precipitation in Shaanxi．The influence of OLR abnormity in sensitive area on autumn precipitation was maily in December of last year，April to June and August;(4)The low value center of OLR over the Qinghai－Tibet Plateau moved to southeast from winter to summer．In September the plateau OLR low value ascension was propitious to increase of precipitation in Tibet Plateau but decrease in the northeast side of the plateau．In October，the low value ascension of OLR was in favor of precipitation increase(reduction)in the plateau(middle Hexi Corridor)．In November both autumn OLR and autumn precipitation had no obvious correlation．The influence of OLR abnormity on autumn precipitation was maily in January，March and June．
Based on the monthly mean data of North Pacific Sea Surface Temperature(SST)and the ten－day precipitation data from 131 observational stations in Northwest China during 1961－2000，the impact of SST anomaly on precipitation of Northwest China from July to the first ten days of September are analyzed by using Singular Value Decomposition(SVD)method．The results show that the precipitation of Northwest China from July to the first ten days of September was closely related to the north Pacific SST anomaly in cor- responding period，the former spring and winter，which can be used as a good reference for prediction of precipitation from July to the first ten days of September in Northwest China．
The different level rainy days and its homologous precipitation quantity are obtained by using the daily precipitation data from May to September ( 1960 － 2004) of 17 stations in the Qilian Mountain area，thus，we know the daily precipitation intensity of light rainfall and moderate rainfall( and more) at each station． Based on regional mean value of the different level rainy days and rainfall intensity in Qilian Mountain area，the tendency of the different level rainy days and rainfall intensity was analyzed using linear trend coefficient and 5 levels main value function． The results show that both precipitation and different level rainy days from May to September in Qilian Mountain area presented more in the west side and less in the east side in the same latitude area，and more in the east and less in the west part of Qilian Mountain． In recent 45 years，the light rainfall days was descending，but the moderate rainfall days was ascending． The precipitation intensity of light rainfall and moderate rainfall ( and more) presented ascending trend too from May to September in Qilian Mountain area． The morlet wave analysis show that the light rainfall days had a period of five years，but the period of the moderate rainfall ( and more) days was more complex．
Over the past 50 years, temperature in the Northwest China p resented a significant rising trend, while p recip itation change was different in different p lace. Warming and drying trend is evident in the whole Northwest China, but the local appearswarming and wetting phenomenon. With the global warming, glaciers retreat and snow line rises, permafrost melts, wetlands degradation, lakes shrink, river flows decrease, water resource becomes scarcer, and eco - environmental degradation. According to IPCC forecast results, the climate warming trend in this region in the future will be more p ronounced. The countermeasures to p rotect the ecological environment, imp rove the comp rehensive climate change monitoring system, launch specific research on the key regional climate changep rocesses, and other suggestionswere put forward.
The app lication of K drought index for droughtmonitor operation in Gansu was introduced in this paper, and the mainly analysiswas as follows: the definition, grades, criterion, app lication of K drought index, and the comparison between monitor results of K drought index and actual drought situation. Results indicate that there is a good effect in droughtmonitorwith K index compared to actual drought situation in sp ring, May, June, July to August, and Sep tember in 2008 in Gansu p rovince.
The mainly research development over Qilian Mountain region in recent ten years is reviewed in this paper. The most research work focused on climate change and water resource. There are a lot of results about the paleoclimate and the interannual variability of neoteric climate and water resource over the QilianMountain region. The exp loitation and utilization of airwater resource over QilianMountain has been focused in recent years, which should be a way to mitigate water shortage in arid and semi - arid region in northwest China.
Based on the radar dense data of convectional cloud on June 12，2004 in Yongdcng county, choosing two similar convectional clouds as seeding and non一seeding cloud，the remarkable changes of radar echo parameters of the seeding cloud compared with the non一seeding cloud were discussed in this paper, and the rain enhancement effect was evaluated primarily with ground observational rainfall data. "hhc results show that many aspects of the seeding cloud，such as precipitation，life characteristic and vertical characteristic parameters change of radar echo, had remarkable differences compared with the non一seeding cloud，and about }0 min after seeding() .6 mm precipitation produced，while the non一seeding cloud experienced a short period from development to dissipation and didri t produce any precipitation in the ground，which can conclude this rainfall cnhanccment experiment reached some prospective effect.
By using the data of monthly surface runoff of Shule，Heihe and Xiying rivers，and spring wheat yields in Zhangye，Jiuquan and Wuwei regions more than 40 years，the impacts of the surface runoff of inland rivers on the spring wheat yields in Hexi region were analyzed.The results show that the spring wheat yieldis increasing fluctuatly due to the development of irrigation，agricultural technology and improved variety，additionally，it’s also impacted by the source of irrigation.The difference of runoff in spring could lead to annual fluctuation of spring wheat yield，short-term fluctuation of annual runoff impacts on yield is small butlong-term fluctuation is larger，especially the long tendency of runoff in spring decides measuring the amount of water inreservoirs，so it shows that agricultural production is impacted by climate change.
Using the data of aircraft artificial precipitation enhancement operation from 1991 to 2002 in Cransuprovince，the situation of it was analyzed statistically in late spring and early summer. According to the characteristic of weather system of Cransu，making use of sounding data and basing `discriminant model'，we can educe three types of high一level circulation of precipitation. These types were straight but some fluctuant，southwest and northwest air current weather system，respectively. Among the types，the straight but somefluctuant air current weather system emerged morefrequently. The typesof weather system of aircraft artificialprecipitation enhancement operation were sorted by `discriminant model'，result showed that the main type of aircraft artificialprecipitation enhancement operation was straight but some fluctuant air current weather system also，and the next type was southwest air current weather system.
