树轮宽度指示的川西色达7月平均最高气温变化

Change of Mean Maximum Temperature in July during 1506-2008 in Seda of West Sichuan Plateau According to Reconstructed Tree-ring Series

利用采自川西高原热基沟地区的树木年轮样本,建立了该地1506—2008年树轮宽度标准化年表。年表与川西高原色达和壤塘气象站前一年10月至当年9月的气候资料的相关分析结果显示,该年表与色达气象站7月平均最高气温相关较好,呈显著正相关关系,相关系数达0.63。利用该年表重建了该地区1506年以来的7月平均最高气温序列,通过＂逐一剔除法＂进行交叉检验,发现重建方程稳定可靠,方差解释量为39.7%。重建序列显示：暖期时段有5个,为1512—1548、1577—1590、1612—1660、1670—1687年和1704—1784年;冷期时段有7个,为1549—1579、1591—1611、1688—1703、1785—1828、1837—1856、1863—1902年和1962—1998年。同时,利用功率谱和小波分析法进行周期信号检测,发现重建序列存在着显著的周期振荡,主要有80~130年、24~33年、7~16年和2~3年左右的振荡周期。

Tree-ring chronologies during 1506-2008 was constructed by tree-ring samples from Rejigou in West Sichuan Plateau. Correlation analysis indicated that the correlation were significant among tree-ring chronologies and mean maximum temperature in July at Seda meteorological station in West Sichuan Plat- eau, so a mean maximum temperature series in July during 1506-2008 at Seda was well reconstructed by the tree-ring chronology series and its explain variance was 39.7%. It was verified that the reconstructed series was reliable by leave-one-out cross-validation. The reconstructed series indicated there were five warm periods, which were 1512-1548, 1577-1590, 1612-1660, 1670-1687 and 1704-1784, and seven cold periods, which were 1549-1579, 1591-1611, 1688-1703, 1785-1828, 1837-1856, 1863-1902 and 1962-1998. Wavelet analysis showed that periods of the mean maximum temperature change in July were 80-130 years, 24-33 years, 7-16 years and 2-3 years.