Characteristic Analysis on Evaporation in Hotan City for Recent 40 Years
Based on the evaporation data of Hotan weather station from 1961 to 2000, the Climate changes, such as annual, seasonal, monthly and the inter-decadal changes, sudden changes and so on, of the evaporation are completely analyzed. The results indicate that the seasonal and monthly evaporation present different up-trend in recent 40 years, but annual evaporation is increasing at the trend rate of 48.52mm/10a, and the increases mainly occur in spring and autumn, especially in May. in 1960s, total annual evaporation is relatively less and more in 1980s. Total annual evaporation is tested using the methods of standard Morlet wavelet analysis and accumulative anomaly curve. It indicates that there is a sudden change in 1978. There are about 4 to 6-year, 11-year or 22-year of the periods in the evaporation changes.