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Reconstruction Of Climate Change In West Sichuan With Tree-ring Data

Posted on:2014-04-05Degree:MasterType:Thesis
Country:ChinaCandidate:D M XiaoFull Text:PDF
GTID:2250330401980795Subject:Journal of Atmospheric Sciences
Abstract/Summary:PDF Full Text Request
The purpose of the article is to study the history of climate change in WestSichuan. Tree rings sampled from West Sichuan was employed and their characteristicsas well as their respond to climate change were analyzed. Then the chronology wasestablished. Correlation analysis indicates that the correlation between tree-ringchronology and climatic elements in West Sichuan is significant. There are4reconstructed series. Analyzing the reconstructed series show that:(1)Tree rings sampled from West Sichuan was employed, and then the chronologywas established. The study found that the growth of tree-ring has good synchronizationin the region of the11sample points, the sample reflect the climatic characteristics ofthe region. The correlation analysis indicates: the sample points can be used to extracthistorical information on climate change, but each sample point response to climaticelements there are differences. Overall, in West Sichuan, the temperature is the limitingfactor of the growth of the forest line, and rainfall is not.(2) There are4reconstructed series:The first series. A mean July-September temperature series extending back to1506was reconstructed by tree-ring samples which found in West Sichuan. In the past505years, there were69very warm years and54very cold years, six coldperiods(1511~1526,1530~1548,1577~1590,1612~1659,1677~1688,1704~1784)and nine warm periods(1549~1576,1591~1611,1689~1703,1785~1828,1836~1856,1864~1899,1902~1931,1934~1951,1962~1997). Empirical modedecomposition analysis and wavelet analysis shows that periods of temperature inJuly-September have2~5、7~11、12~26、35~48and120years.The second series. The tree rings standardized chronology series (TRSC) of173years was established based on the tree-ring-width data of Songpan Plateau. Thecorrelations between the TRSC and meteorological elements were analyzed usingpartial correlation methods. It is found that the TRSC responses to precipitation in thetime of May is the most sensitive, so the precipitation of May in Songpan Plateau were reconstructed. Furthermore, the change character of precipitation were analyzed, theresults suggest that, in the past162years, the May precipitation in the Songpan Plateauexperienced4wet periods(1879~1889、1920~1939、1941~1959、1992~2005) and3dry periods(1862~1878、1890~1907、1960~1991). It is found that the periodiccycles about8~10、10~20、32~50and60~80years are significant.The third series. Tree-ring chronologies during1506~2008in West Sichuan wasconstructed by tree-ring samples. Correlation analysis indicated that the correlationwere significant among tree-ring chronologies of Rejigou and temperature in July atSeda and Rangtang stations in West Sichuan, a mean maximum temperature series inJuly of1506-2008at Seda station was well reconstructed. It was verified that thereconstructed series was reliable by leave-one-out. The reconstructed series indicates:there were five warm periods, which were1512~1548、1577~1590、1612~1660、1670~1687and1704~1784,and seven cold periods, which were1549~1579、1591~1611、1688~1703、1785~1828、1837~1856、1863~1902and1962~1998.Power spectrum analysis and wavelet analysis shows that periods of temperaturein July have80~130、24~33、7~16and2~3years.The fourth series. Tree rings of Picea schrenkiana sampled from Jingchuan wasemployed and their characteristics as well as their respond to climate change wereanalyzed. Then the chronology was established. Correlation analysis indicates that thecorrelation between tree-ring chronology and mean temperature in June at Jinchuanstations in West Sichuan is significant. And a mean temperature series in June of1713~2010at Jinchuan station was well reconstructed. According to the meantemperature series reconstructed, the mean temperature is18.24℃. The reconstructedseries indicates: there were three warm periods, including1825~1839,1854~1892and1951~1961,and four cold periods, including1792~1804,1842~1853,1864~1893and1911~1924.Power spectrum analysis and wavelet analysis shows thatperiods of temperature in June have2~3、7~8、20~30、32~64and70~130years.(3)Our reconstruction was validated by other temperature reconstructions fromthe surrounding area and documented climate disaster events, and the reconstructionwork is successful.
Keywords/Search Tags:West Sichuan, climatic reconstruction, climate change, tree-ring, temperature, precipitation
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