Analysis on the Evolvement of Dryness/wetness in Aksu Prefecture in Recent 45 Years

In this paper,the decadal,annual and seasonal changes of dryness/wetness in Aksu Prefecture in recent 45 years are analyzed using the annual and seasonal air temperature and precipitation data observed by the meteorological stations in Aksu Prefecture in recent 45 years based on the dryness/wetness values at the stations.The results reveal that the increase of annual air temperature is higher than that of precipitation,and both annual temperature and precipitation increases occur mainly in winter,especially the air temperature in summer and precipitation in autumn in the regions near the deserts are slightly decreased.The dryness/wetness values reveal that the wetness becomes gradually towards the dryness from the mountainous region to the deserts,and the dryness/wetness value in the mountainous region is about 30% lower than that in the marginal zone of the deserts because of the precipitation difference.The wetting rate is continuously increased in the north mountainous region and the west low-mountain zone but decreased gradually in the east plain.Humidity increase in Aksu Prefecture in recent 20 years is directly related to the increase of precipitation,but aridity occurs in some regions.