A Preliminary Analysis on the Climatic Changes in the Drainage Area of Urumqi River from Tree Ring
Kang Xingcheng ( Lanzhou Institute of Glaciology and Geocryology, Acudcmia Sinica )
Based on six tree ring samples collected in the drainage area of Urumqi River in Augest, 1982, the author analyzed the cold warm spell changes since500Y.B.P. and the dry-wet spell changes since 350 Y. B. P. .It was shown that there were 6 cold spells and 7 warm spells since 500 Y. B. P. . From the early 16th century to the early 18th century, climatic cold and warm alternative changes were frequent; while from the middle period of 18th century to present, it was stable relatively. It was also found that there were 4 cold- warm changing periods which were 302, 151,82 and 62 years respectively and 3 dry-wet changing periods which were 115, 46 and 38 years respectively. These results were in keeping with those of neigh-bouring regions.