1960—2012年西藏林芝气温和降水变化

Wavelet Analysis and Mann-Kendall Test of Mean Air Temperature and Annual Precipitation in Linzhi, Tibet, China from 1960 to 2012

基于1960—2012年日平均气温和日降水量数据,利用小波分析和Mann-Kendall突变分析方法,分析了西藏林芝气温和降水的变化特征。结果表明:林芝年平均气温增长速率0.028℃·a^(-1);年平均气温受3～4 a尺度波动的影响,无明显主周期;年平均气温序列有3个突变点,分别是1972—1973年、1975—1976年和1977—1978年。年降水量增长率1.218 mm·a^(-1);年降水量受4 a、10 a和20 a尺度波动的影响;有两个主周期,分别为2 a、19 a;年降水量序列有4个突变点,分别为1960—1961年、1965—1966年、1977—1978年、1982—1983年。

After making trend analysis, morlet wavelet analysis and Mann-Kendall test were used in this study for analyzing air temperature and precipitation annual variabilityfrom 1960 to 2012 in Linzhi Sta- tion, Tibet, China. It is found that there existed a increasing trend with 0.028℃ a^-1 and characteristic pe- riods of 3-4 years for mean air temperature, but there was no obvious main period for mean air temper- ature, and there were three abrupt changes for mean air temperature, which were the years of 1972-- 1973, 1975--1976 and 1977--1978. There existed a slowly increasing trend for annual precipitation with 1.1218 mm a^-1, there also existed characteristic periods of 4 years, 10 years and 20 years for annual pre- cipitation, and there were two main periods of 2 and l0 years for precipitation, there were four abrupt changes for precipitation, which were the years of 1960-1961, 1965-1966, 1977-1978 and 1982-1983. Key words： Linzhi; Wavelet analysis; Mann-Kendall test; air temperature; precipitation