Variation Characteristics of Temperature and Precipitation in the North of Tianshan Mountains in Recent 50 Years

Based on the data of daily maximum temperature,daily minimum temperature,daily mean temperature and daily precipitation at 8 meteorological stations in the north of Tianshan Mountains from 1961to2010,the climate change was analyzed by linear trend analysis,sliding average method,Mann-Kendall test method,Hurst index method and so on.Results showed that the average annual temperature and precipitation increased in the north of Tianshan Mountains in recent 50years.The linear increase trends were 0.26℃/decade and 15.67mm/decade,respectively.The warming trend was obvious in winter,showing a rate of about 0.49℃/decade,followed by autumn with a rate of 0.35℃/decade.Precipitation increment was about5.44mm/10ain summer which was largest in all seasons.The abrupt examination indicated that the annual mean temperature and precipitation had the discontinuous ascension in 1996and 1983,respectively.The future temperature and precipitation would present a trend of increase on the whole.The extreme high temperature indices increased and the extreme low temperature indices decreased.Among the extreme precipitation indices,the longest continuous days without precipitation and the days without precipitation presented diminishing trend with different degrees,while one-day maximum precipitation and extreme rainfall days presented increasing trend with a ratio of 1.36mm/decade and 1.81d/decade.Meanwhile,the differences in their spatial distributions were significant.The extreme temperature indices correlated with annual mean temperature,and extreme precipitation indices correlated with annual precipitation too.