The Study Of Dendroclimatology In Aksu River Basin, Southern Slope Of Tianshan Mountains

In this paper, the tree ring samples of Picea schrenkiana Fisch.et Mey collected from six sites in Aksu River Basin, southern slope of Tianshan Mountains in 2005, are used to development six tree ring width chronolgies using standard dendrochronological methods. Compared some statistics parameters of the six tree-ring standardized chronologies from ARSTAN program, found that the Xiaokuzibayi and Ying'atehe chronologies contents more climatic information. Single correlation calculation indicated, using precipitation of Aksu Meteorological station from last August to April and tree-ring standardized chronologies can be better reconstructed recent 610 years'precipitation of Aksu River Basin, using temperature of Aksu Meteorological station from February to March and tree-ring standardized chronologies can be better to rebuild the region recent 378 years'temperature from February to March, and using dusty days of Aksu Meteorological station from April to July and tree-ring standardized autoregressive chronologies can be better reconstructed the region recent 611 years'dusty days. Each has obvious significance of the tree physiology, and through various test results of the reconstruction are credible.Through analysis, in Aksu River Basin, precipitation is primary limiting factor of tree radial growth, and temperature affect is is the worst. Analyse the characteristics that precipitation,temperature, and dusty days of historical period we found:On the 0.05 significance level, the precipitation over past 610a in Aksu River Basin, southern slope of Tianshan Mountains had 2-2.5a,12-13a,45a,50a and 58a changing cycle, in the past 378a,February-March average temperature had 3.5-3.6a,42a and 50.4a period,and the dusty days over past 611a had 2.3a,4.1a,5a,6.8a,8.8a,10.7a,45.1a and 50.7a quasi-periodic changes.The precipitation series had abrupt change in 1584,1615,1685,1722 and 1753, is stable in 15^th,19^th and 20 th.The temperature from February to March series had abrupt change in1719 and 1827. The dusty days series had abrupt change in 1434,1685,1721,1752,1776,1798 and 1865, is stable in 16th and 20th . The abrupt change in 1685 and 1721 of dusty days series correspond with the precipitation series,but the opposite direction.The precipitation reconstructed series has nine dry and nine wet stages, the most drought stage is 1722-1752 , the year 1894 to 1911 is the most humid stage, the average rainfall is up to 72.5% partial. The temperature reconstructed series has nine warm and nine cold stages, the year 1911 to 1922,which is the coldest stage, lower than average 1℃above, and the year of 1640 to 1651 is the warmest stage, higher than the average 1℃.The dusty days reconstructed series has nine more stages and ten less stages, in the stage of 1752-1775,appeared the least sand and dusty weather, ,and appeared the most dusty weather in the stage of 1547-1559.There was a negative correlation between the dusty days change stage and the precipitation change stage,the precipitation can restrain dust and sand strom occur.From the scale of a century,arid year more than humid year in every century, the precipitation of 15^th ,19^th and 20^th century is relatively stable. The climate in the Basin of Aksu River turn to wet, the 15^th and 17^th century is relatively drought,each of the early century (25) compared to other time slots are manifested humid. The trend of precipitation interannual change is uneven, natural disasters (water, drought, snowstorm) frequent. From 15^th to 17^th ,the dusty days significantly increase, then reduce.Comparative analysis precipitation that the southern and the northern slope of Tianshan Mountains over the past 235 years we found: The precipitation that the southern and the northern slope of Tianshan Mountains is a huge difference,but the changes in the trend have better synchronization,and Wet and dry stage counterparts is better.