Variations of Drought and Influencing Factors in Lancang River Basin
Based on the daily data of 10 meteorological stations in the Lancang River Basin from 1961 to 2010, the annual and monthly humid indexes are calculated by Penman-Monteith model with the extreme drought frequency. According to the calculated data, the spatial and temporal characteristics of the arid climate have been analyzed, as well as its impact factors. The results indicate that there is an obvious decreasing trend in annual precipitation and humid index, with the precipitation trend rate of 2. 095 mm per 10a and the humid index 0. 006 per 10a respectively; inversely, the annual temperature and potential evaporation have an increasing trend with the temperature trend rate of 0. 276 degrees centigrade per 10a and the potential evaporation 6. 231 mm per 10a; from 1961 to 2010,the Lancang River Basin experiences five stages, namely comparatively cold dry, cold humid, cold dry, warm humid and warm dry; it is extremely obvious in winter and spring;the average humid indexes gradually increase from upstream to downstream;the humid indexes in the upper-middle reaches show an increasing trend but it decreases in the down reaches; the frequency of extreme arid events declines from 1961 to 2010 in the Lancang River Basin while it increases in the lower reaches with the rate of 0. 010 3 per year; in the 1960s, extreme arid events occurred frequently in the Lancang River Basin; the precipitation and sunshine durations were the key factors for affecting humid index.
humid indexextreme arid eventsmeteorological elementLancang River Basin
NETL
NSTL
万方数据
维普
