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．

Soil heat flux plays an important role in energy flux exchange between land and atmosphere, especially in arid and semi-arid region. Based on soil heat flux at Zhangye National Climate Observatory, the diurnal variation of soil heat flux and the relationship between that and radiation flux are analyzed under different weather conditions for clear, cloudy and rainy day.The results show that the soil accepted heat from the air on clear day, on the contrary, the output heat of soil exceeded the input on cloudy and rainy day. In addition, most values of soil heat flux are negative in autumn and winter season, and positive in spring and summer .

Based on five - layer wind speed, air temperature, humidity and vapor p ressure of the gradient tower of Zhangye National Climate Observatory built in 2007 from Sep tember 2007 to August 2008, the percentage of missing value was calculated, and the climate characteristics of Zhangye in different seasons were also analyzed. The reliability of data from the gradient towerwas checked by comparing with some other observational stations.

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.