The characteristics and influence of the serious drought event lasting eleven years ( 1922 － 1932) in the Yellow River valley
was analyzed in this paper． The result shows that this serious drought event occurred at least once in two hundred years． It happened in
the relatively warmer period under the background of a century － scale drought，which was characterized by long time，wide area，and
heavy damage． During the period of 1922 － 1932，the natural disasters such as drought，locusts，earthquakes，pestilence intertwined
with the man － made disasters ( banditry and war) ，which led to a terrible calamity in the Yellow River valley，the entironment and agricultural
productivity suffered great devastation，and the people underwent all kinds of hardships．

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 extreme drought eventoccurred in Sichuan and Chongqing region during the period of1935-1937 was analyzed. Itwas an extreme drought event thatmeet in one hundred years in warmer climate period, itpersisted long time and disserved severely, and people’s life and wealth suffered bigness harm. The low ability ofdefence droughtdisaster resulted in seriouse calamity. People in Sichuan and Chongqing regionmust strengthen defence drought and reduction disasterwork under the back ground ofglobal climatewarming.

Based on theM ICAPS, T213 mathematical forecast p roducts, aerological observations from 34 stations in forecast key area and p ressure, p recip itation data for different time in Baiyin, the weather patterns of p recip itation over 10 mm in Baiyin are generalized by analyzing the synop tic character, and according to them an objective quantification group ing ismade. Some indices and p rediction factorswith physical significance on p recip itation over 10 mm are selected, and a short - period forecastmodel for p recip itation over 10 mm is built by using the PP numerical interp retable and app lied method. Finally, a forecast test from June to August in 2007 ismade, it shows a excellent results that the average forecast accuracy reaches 66. 7%.

11he climatic variation feature of the first and tIIe last dates for thunderstorm occurring and thunderstorm days in tIIe middle part  of Gansu province was analyzed by using observations of4 stations in Baiyin from 1958 to 2005 based on statistics methods of linear tend-encv estimate and wavelet analysis．Results show that the first dates of tIIunderstorm presented a delay trend(2．7 d／10 a)in the north plain：the last dates were ahead(一2．6 d／lO a)in tIIe north plain and presented parabola change in tIIe soutII mountain area．The first date variation of thunderstorm in the north plain Was steadier than that in tIIe south mountain 81"PAl，whereas tIIe last date variation of thun -derstorm in the south mountain area was steadier than that in the north plain，an d the first date change Was steadier than that of the last date of thunderstorm．Th e corresponding threshold of5一da y average temperature Was 9℃ and ll℃ in tIIe north plain for the first and last dates．respectively，and 6℃ in the south mountain．Thunderstorm days were more in tIIe soutII and less in the north，the period of8—10 vears was remarkable before the middle of the 1980s and the general trend of thunderstorm days Was decreasing．

11he climatic variation feature of the first and tIIe last dates for thunderstorm occurring and thunderstorm days in tIIe middle part of Gansu province was analyzed by using observations of4 stations in Baiyin from 1958 to 2005 based on statistics methods of linear tendencv estimate and wavelet analysis．Results show that the first dates of tIIunderstorm presented a delay trend(2．7 d／10 a)in the north plain：the last dates were ahead(一2．6 d／lO a)in tIIe north plain and presented parabola change in tIIe soutII mountain area．The first date variation of thunderstorm in the north plain Was steadier than that in tIIe south mountain 81"PAl，whereas tIIe last date variation of thun derstorm in the south mountain area was steadier than that in the north plain，an d the first date change Was steadier than that of the last date of thunderstorm．Th e corresponding threshold of5一da y average temperature Was 9℃ and ll℃ in tIIe north plain for the first and last dates．respectively，an d 6℃ in the south mountain撇．Th understorm days were more in tIIe soutII and less in the north，the period of8—10 vears was remarkable before the middle of the 1980s and the general trend of thunderstorm days Was decreasing．

Based on meteorological data and social - economy data，the paper analyzed the characteristic of meteorological disasters occurred in Gansu province，the fact of climate change during recent 50 years was also observed. The results show that the ecological environment has been significantly affected by global warming and unreasonable human activities in Gansu province. The adaptive policies of climate change and sustainable development were also discussed in the paper.