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The Dendroclimatological Study On The East Part Of The Northern Slope Of Tianshan Mountain,Xinjiang Province

Posted on:2010-06-22Degree:MasterType:Thesis
Country:ChinaCandidate:X J ChenFull Text:PDF
GTID:2120360278961826Subject:Physical geography
Abstract/Summary:PDF Full Text Request
According to tree-ring width samples of the east in the northern slopes of Tianshan mountains,Xinjiang. Correlation calculation indicates that the correlations were significant between the tree-ring chronologies with the precipitation(from July last year to June current year )and temperature (Summer June) of the East of the Northern Slopes of Tianshan Mountains in Xinjiang, with the greatest single correlation coefficient is 0.597(Sign. Level:0.000006) and -0.437(Sign. Level:0.001). Using the tree-ring width standardized chronologies of SBG t+1,SBG t,CTG t , the long-term sequence of precipitation was reconstructed, with an explained variance of 45.0%; at the same time, using the tree-ring width standardized chronolologies of ZDG t+1,ZDG t+2,BYX t+1,XHG t,DDG t+2, the long-term sequence of temperature was reconstructed, with an explained variance of 43.5%. 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 East of the Northern Slope of Tianshan Mountain in Xinjiang is intensively limited by the precipitation(from July last year to June current year )and temperature (Summer June). The result has distinct physiological significance. the reconstructed equation was stable by crossing-test.(2) In the 301 years, the precipitation of the East of the Northern Slope of Tianshan Mountain in Xinjiang has 7 wet stages and 6 dry stages. And there were 160 dry years, more than wet years. The longest drier stages:1730—1776, less 6.2%, the longest wetter stages:1869—1906, more 5.8%. The driest year is 1944, less 40.2%, the wettest year is 1791,more 48.0%. The wettest stages:1777—1804, more 9.6%, the driest stages: 1841—1868, less 9.0%.In the 158 years, the mean minimum temperature of June in the East of the Northern Slope of Tianshan Mountain in Xinjiang has 118 normal years (74.7%); warmer years: 19(12.0%); cooler years: 18(11.4%); cold summer: 2(1.3%); hot years: 1(0.6%); According to the extreme value of mean minimum temperature of colder years in this stages, the least value of mean minimum temperature occurs in 1849, 11.19℃, lower 2.19℃; the maximum value occurs in 1851,15.80℃, higher2.42℃. The longest warmer stages is 1918—1935, the mean minimum temperature is 14.04℃, higher 0.66℃; the longest cold Spring stages is 1936—1962, the mean minimum temperature is 12.93℃, lower 0.45℃. The long-term change periods of precipitation and temperature are greatly similar to that of the changing trend of Xinjiang and China's north-western, and there are some inherent and intricate relationships and responses between them.(3) The reconstructed long-term precipitation sequence had 2.0a,2.8a,3.6a,3.7a,11.1a,50.0a,66.7a,100.0a changing periods. The reconstructed precipitation had abrupt change in 1741,1764,1804,1869,1905. The reconstructed long-term temperature sequence had 2.0a changing periods. The reconstructed precipitation had abrupt change in 1907,1936.
Keywords/Search Tags:tree-ring chronology, East of the northern slope in Tiantian maintain, reconstruction of precipitation and temperature, climate change, analysis of characteristic
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