The Dendroclimatological Study On The West Of Northern Slope Of South Tianshan Mountain In YiLi

Correlation calculation indicates that the correlations were significant between the tree-ring chronologies with the precipitation(from July last year to May current year )and temperature (June to July) of the West of the Northern Slope of South Tianshan Mountain in YiLi,with the greatest single correlation coefficient is 0.622 and -0.588(The significant is more than 99.9%). Using the tree-ring width standardized chronologies of KRKt,XBDt+1,QKSt+2, the long-term sequence of precipitation was reconstructed, with an explained variance of 58.7%; at the same time, using the tree-ring maximum gray value standardized chronolologies of AHYt+1,QLKt+1,ALSt,QKSt , the long-term sequence of temperature was reconstructed, with an explained variance of 55.2%.It is verified that the reconstructed precipitation and temperature were reliable.Analyzing the reconstructed series show that:1) The growth of the alpine timberline spruce on the West of the Northern Slope of South Tianshan Mountain in YiLi is intensively limited by the precipitation(from July last year to May current year )and temperature (June to July).The result has distinct physiological significance. the reconstructed equation was stable by crossing-test.2) In the 235 years, the precipitation on the West of the Northern Slope of South Tianshan Mountain in YiLi has 8 wet stages and 8 dry stages. And there were 92 normal years,23 dryish years,100 dampish years ,2 dry years and 18 wet years; The great wettest periods was 1996-2004 (the mean precipitation was 409.9mm,8.75% higher than that of the recent 44years) ,and the great driest periods was 1854-1868 (the mean precipitation was 328.04 mm, 10.8% lower than that of the recent 44 years).In the 216 years, the spring mean temperature on the West of the Northern Slope of South Tianshan Mountain in YiLi has 8warm stages and 8 cold stages. And there were 153 normal years,18 warmish years,32 coldish years ,8 warm years , 3 cold years, 2 extra-warmer years .The most warm temperature is 15.82℃(1873) ,which is 3.62℃higher than that of recent 46years, and The most cold temperature is 13.48℃(1836) ,which is 2.34℃lower than that of recent 46years,and the longest warmish periods was 1974-2005 (32 years).the longest coldish periods was 1861 -1889(29 years).The long-term change periods of precipitation and temperature are greatly similar to that of the changing trend of Xinjiang, China and the Northern Hemisphere, and there are some inherent and intricate relationships and responses between them. The long-term change periods of precipitation and temperature are greatly similar to that of the change trend of Xinjiang, China and the Northern Hemisphere, and there are some inherent and intricate relationships and responses between them.3) The reconstructed long-term precipitation sequence had 2.1-3.05a,31.2a changing periods. The reconstructed precipitation had abrupt change in 1824,1869,1912and1928.The reconstructed long-term temperature sequence had 2a,10~11a,48a,72a changing periods. The reconstructed precipitation had abrupt change in1887,1918 and 1935The periods of precipitation and temperature were varied with time, and the 50a low frequency cycle was the most obvious among them.At the same time the high-frequency cycle of temperature had very weak performance in the 20th century.