Analyses of Variation Characteristics and Abruptness of Temperature-Precipitation of Typical Basin in Jiaodong Peninsula Hilly Watersheda——Case Study of the Dagujia River

Based on the long-term data(1966~2003) of the annual and monthly temperature and precipitation obtained from the hydrological stations of the Dagujia River basin,the annual and seasonal characteristics of climate change trend and abruptness were analyzed by using the linear trend estimation and Mann-Kendall methods.The results showed that,①in recent 40 years,the annual mean temperature presented an evident increasing trend,while the precipitation decreased obviously.The climate change rates were 0.20℃/10a and-42.17 mm/10a,respectively.②The seasonal mean temperatures of spring,summer and winter had an increasing trend,while the autumn decreased;the temperature change rate of spring and winter(0.216 ℃/10a and 0.583℃/10a) was higher than that of annual mean temperature,and the summer change rate(0.01 ℃/10a) was lower than that of annual mean temperature;seasonal precipitation trend was similar to that of annual,but the decreasing scope was obviously lower than that of the annual temperature.The precipitation of summer and autumn decreased rapidly,while it decreased slowly.The change rates of precipitation in summer,autumn,spring and winter were-21.76mm/10a,-15.52 mm/10a,-2.52 mm/10a and-2.25 mm/10a,respectively.③Except the winter,the seasonal and annual mean temperature abruptness occurred in 1972 or so,and the second abruptness appeared in summer of 1994.The autumn had more abruptness points compared with other seasons.Most of the precipitation abruptness took place in the beginning of 1970s and 1980s.