青海高原地区近250a来年平均气温变化及突变分析

Annual Mean temperature Variation and Analysis on Its Abrupt Change in Recent 250-year in the Qinghai Plateau

用多条树轮重建的青海高原近250 a平均气温序列,利用线性趋势、小波变换分析和突变检测等方法对近250 a青海高原年平均气温的年际变化及突变特征进行了综合分析,结果表明:250多a来青海高原年平均气温波动明显,30 a滑动平均表现出1779～1811年和1934～2006年年平均气温偏高,其中年平均气温最高出现在1998年为1.3℃,1741～1778年和1812～1933年年平均气温偏低,其中年平均气温最低出现在1823年为-1.5℃,年气温总体呈上升趋势;在20 a以上相对大尺度上,年平均气温冷、暖交替的特征明显,经历了7个冷、暖交替阶段,在2～3 a,28 a左右,48 a和110 a时间尺度上的周期变化都比较明显。

Based on the 250 - year annual mean temperature sequence reconstructed by multi - piece of tree - rings in the Qinghai Plateau, the abrupt change characteristics and inter - annual variation of annual mean temperature there are synthetically analyzed by using methods of linear tendency, wavelet analysis and abrupt change test. The result shows that annual mean temperature fluctuated remarkably in recent 250 years in the Qinghai Plateau, and the 30 - year moving - mean presented higher annual mean temperature during 1779 - 1811 and 1934 -2006, and the highest annual mean temperature （ 1.3 ℃ ） in 1998; while lower annual mean temperature during 1740 - 1778 and 1812 - 1933, and the lowest value（ - 1.5 ℃ ） oceurred in 1823, but annual mean temperature generally kept rising. On relatively large scale beyond 20 - year, the seven alternations of coldness and warmness for annual mean temperature appeared obviously. On time scales of two to three years, 28 -year, 48 -year and 110 -year, the cycle variation was comparatively evident.