西藏林芝地区近350a来降水变化及突变分析

Variation and Abrupt Change of Precipitation in Nyingchi Prefecture of Tibet Autonomous Region in Past 350 Years

利用树轮δ13 C序列 ,重建了公元 16 5 0年以来林芝地区秋季降水量序列 ,分析了近 35 0a来降水的阶段性变化和趋势 .用小波分析的方法探讨了不同时间尺度降水变化周期的复杂性 ,结果表明 :降水变化在不同层次和时段上存在显著 2～ 3a、13a和 36a左右周期 .突变分析发现 ,林芝地区秋季降水存在明显的突变年份 ,随时间尺度的变短 ,发生突变的次数增加 ,体现了气候变化的层次性 .

Reconstruction of autumn precipitation from stable carbon isotope series in Nyingchi Prefecture of Tibet Autonomous Region, together with the trend and phase analyses of past 350 years precipitations by method of wavelet, it is found that there are about 2～3 years, 13 years and 36 years cycles in precipitation series. The complex of precipitation period and abrupt change at different time-scale using the methods of wavelet and moving-t is analyzed. Finally the possibility due to abrupt climate change is discussed. The shorter the time-scale, the more abrupt change occurs.