【作者】 喻树龙；

【导师】 袁玉江；

【作者基本信息】 新疆师范大学 ， 自然地理学， 2011， 硕士

【摘要】 为了研究巩乃斯地区树轮密度对气候响应并重现该区域的历史气候变化,本文利用巩乃斯地区天山云杉树轮资料建立树轮密度年表,分析其年表特征,并由相关和响应面方法分析了树轮密度年表对气候因子的响应。采用多种去趋势法,建立最佳气候响应密度年表,据此重建了伊犁地区东部7条历史气候序列,分析重建气候序列特征,最终得到以下几点结论:⑴在巩乃斯山区,早材平均密度和最小密度的高频气候信息随海拔高度的增加而减少,树轮晚材平均密度和最大密度的同步变化则随之增强,该区域森林上树线的树轮密度年表与天山北坡中部密度年表具有较好的相关性。⑵在生长季以前,森林中下部林缘的早材平均密度与气温呈负相关而与降水为正相关,在生长季则正好相反。中下部林缘的早材平均密度的形成主要受4-8月的降水的影响,晚材平均密度则同时受气温和降水的制约。影响森林上树线树轮晚材平均密度变化的主要气候限制因子是7-8月的气温,这与国际上在湿冷区域树木年轮最大密度与夏季气温有密切的相关性的研究结论相一致。PDSI与早材平均密度和最小密度的相关性是森林中下部林缘好于林中和上树线,而PDSI与晚材平均密度和最大密度的相关则表现为林中要好于中下部林缘和上树线采点,而且林中采点的相关系数绝对值随着月份的推迟而增大。⑶利用由不同去趋势法建立的密度年表重建了4-8月的雪崩站平均气温、降水量、新源站平均气温、最高气温、最低气温、降水量以及PDSI指数,经验证,虽然新源平均气温、最低气温和降水量的重建序列在高频信息上有一定的损失,但重建结果是可信的。在重建序列中,新源平均气温和最高气温的空间代表性最好。⑷在1835-2005年,巩乃斯地区最冷阶段出现在1835-1839年和1950-1959年,最暖阶段在1870-1879年,最干阶段在1860-1869年,最湿阶段在1840-1849年,在19世纪末20世纪初出现的清末冷湿期在北疆的西部和中部均有出现。4条4-8月气温重建序列的主要周期有3a、6a、14-15a,56-57a和84-91a,3条4-8月降水和PDSI重建序列的主要周期有3a,4a,6a,7a,43-59a。巩乃斯地区在1858-1859年、1881-1886年、1944-1948年和1975年左右出现了气温突变,在1856-1857年、1884-1885年和1984-1985年左右发生降水突变。更多还原

【Abstract】 The purpose of the article is for first time to study response relationship between tree-ring density and climatic factors and climate reconstruction in Gongnaisi. Some master ring-density dating chronologies was developed by data of spruce. It analyzed character of statistics among the density chronologies indices and response of climatic factors on tree-ring density through correlation method and response surface method. By means of stepwise regression and different detrending methods, seven climatic series was reconstructed by density chronologies of high sensitivity. Analyzing the reconstructed series show that:(1)The character of statistics that tree-ring density change was aroused by increscent elevation in Gongnaisi region was showed: high frequency information of springwood density and tree-ring minimum density was some decrease and synchronism of summerwood density and tree-ring maximum density was increase when elevation increase. It is best from western and middle of Tianshan mountain in upper forest limit that analysis representation of tree-ring density in circumjacent area.(2)Springwood, summerwood density of the lower forest limit and summerwood density of the upper has regularity to response of climatic change, but springwood density of the upper is different. Precipitation from April to August influences growth of springwood density in the lower limit of regional forest. Limitative factor of tree-ring density development in the upper limit is temperature from July to August. It was same result that is distinct correlation between tree-ring maximum density and summer temperature in the international. Correlation coefficient between density of springwood and minimum and PDSI in the lower limit is better than in the upper and middle region of the forest. it of between density of summer and maximum and PDSI in middle region of forest is more value than in upper and lower and its absolute value increase when late mouth come.(3) Tree-ring density chronologies were developed by different t detrending methods like as smoothing spline function of 60 to 180 step size, regional curve(RCS) and general negative exponential curve. Some high sensitivity density chronologies was selected through correlation coefficients between the chronologies and climatic factor, seven climatic series were reconstructed by the chronologies. The series include average temperature and precipitation of Tianshan mountains snowcover and avalanche station, average temperature, maximum air temperature, minimum air temperature and precipitation of Xinyuan station, and Palmer Drought Severity index of the region from April to August. It is widely validated that the reconstructed series is credible by means of leave-one-out and bootstrap methods. But high frequency information of average temperature, minimum air temperature and precipitation series of Xinyuan station had some loss. Space representative of average temperature and maximum airtemperature of Xinyuan station is best among this series. (4)In 1835-2005, the coldest phase were 1835-1839 and 1950-1959 years, the warmest phase was 1870-1879, the drought phase was 1860-1869 and the wet phase 1840-1849 in Gongnaisi region. Clammy phase at the end of qing dynasty is same exist in central regions and western of Tianshan mountain. The reconstructed long-term temperature series sequence had 3,6,14-15,56-57 and 84-91a changing periods. The series had abrupt change in 1858-1859,1881-1886,1944-1948 and 1975. The reconstructed precipitation and PDSI series had 3,4,6,7 and 43-59a changing periods and had abrupt change in 1856-1857,1884-1885 and 1984-1985 years. The short cycle meanwhile appeared because driving factors of the periods influence temperature and precipitation of the regions at the same time, but the influence impact strength is different at different phase.更多还原