Study On Variation Character Of Water Cycle Elements Basing On Different Methods In Hotan Oasis

Water gestate and maintain the full life in the Earth, water is the important resource to humanity production and living, each several part of nature is contacted by water cycle, forming a organic integer. Owing to influence of human activities and climatic change on water cycle, it is concerned by hydrologists for the moment. Hotan oasis is in a certain natural condition, precipitation is rare, evaporation is big, and it is most drought and aridity in the oasis. In the irrigation and environment protect project (phase II) supported by the World Bank, the Hotan subproject area includes Hotan, Moyu and Luopu Counties, with the total area of 3592 km2 , accounting to 31.98% of the whole prefecture. This study is on the background of the irrigation and environment protect project (phase II), the variation rule of water cycle elements of Hotan oasis is investigated by methods wavelet analysis, spectrum analysis and so on, which may be significance to the prediction of hydrological elements and then the efficient utilization of water resources.Based on data collection and analysis, with the methods of Mann-Kendall and Spearman rank correlation test, wavelet analysis, spectrum analysis and so on, the main results were obtained as follows:(1) Annual air temperature and evaporation have obvious increasing trend. Annual precipitation have indistinctive increasing trend. Annual humanity, annual runoff of Tongguziluoke gauging station and Wuluwati gauging station have indistinctive degressing trend.(2) Annual air temperature have 18 years scale, 8 years scale, 3 years scale period, which are the first, second and third main period respectively. 4 years scale period is the first mainperiod and 15 years scale period the second main period for annual precipitation. 14 years scale period is the first main period; 7 years period and 3 years scale period are the second and third main period in turn of annual evaporation. 15 years scale period, 11 years period, 4 years period are the first, second and third main period in turn of annual humanity. Annual runoff of Tongguziluoke gauging station have 18 years scale period, 8 years scale period, 5 years scale period, 3 years scale period. Annual runoff of Wuluwati gauging station has 5 years scale period and 7 years scale period.(3) Precipitation and air temperature have influence on evaporation, and precipitation, air temperature and evaporation have influence on humanity.(4)It is shown by the investigation that using combined method of wavelet analysis and Mann-Kendall rank correlation test may analyze the trend pattern in reason and practically.(5) It is shown by the investigation that calculating the main period with wavelet analysis has superiority, and the results are more reasonable.