【作者】 田洪阵；

【导师】 杨太保；

【作者基本信息】 兰州大学 ， 生物地理学， 2013， 博士

【摘要】 祁连山地处我国西北干旱半干旱地区,是我国重要的生态屏障,是亚大陆型冰川与极大陆型冰川的过渡地带,是我国现代冰川研究的发祥地。祁连山冰川变化研究不仅具有重要的科学意义,同时也具有重要的生态意义和社会意义。本文利用Landsat卫星TM、ETM+影像,在数字高程模型和第一次中国冰川编目数据的辅助下提取了1990年、2000年和2010年三个时段的整个祁连山区的冰川边界信息,并对其空间分布特征和空间变化特征进行了分析。另外结合我们提取的其它山系的冰川面积信息和已发表的研究成果,通过数据整合,我们计算得到了我国冰川约半个世纪以来的变化信息,并对其时空变化特征进行了分析。同时我们还分析了气温、降水和零度层高度在1961年至2010年间变化的时空特征。结合气候变化的时空特征,我们分析了冰川变化的控制因素,利用该分析结果,我们分析了冰川变化对温度变化的时间滞后性。根据滞后性分析的结果,我们建立了温度与冰川变化之间的经验模型,最后以气候模式的预测结果作为输入,利用该经验模型预测了未来冰川变化。本文的主要结论如下：(1)祁连山区冰川面积的分布特征：a、在高程上,冰川的分布形态类似正态分布,其峰值出现在海拔5,000米左右；b、冰川主要分布在朝北的坡向；c、冰川分布随冰川规模增大面积变大；d、祁连山西部地区冰川分布面积大于东部地区。(2)冰川面积的变化特征：a、1990年至2010年祁连山区冰川面积缩小了22.8±3%,2000年至2010年相对1990年至2000年退缩速度有所加快；b、祁连山区低海拔的冰川退缩速度高于高海拔地区,以海拔5,000米为大致分界点,近十年冰川在高海拔地区退缩速度减慢；c、在祁连山区,在南向的坡向的冰川退缩速度大于北向坡向的退缩速度,而南向坡向中又以西南坡向的退缩速度最大；d、在祁连山区,小规模的冰川退缩速度快,而大规模的冰川退缩速度慢,且不同规模的冰川均表现出2000年至2010年间的退缩速度较1990年至2000年间的退缩速度加快；e、祁连山区东部的冰川退缩速度快于西部；f、1956年至2010年间祁连山区的冰川整体处于退缩状态,面积减小了30.36%,年均退缩率为0.56%,1963年至2010年,我国冰川整体处在退缩状态,面积减小了15.7%,年均退缩速率为0.33%；g、在过去约半个世纪里,青藏高原周缘地区冰川退缩比例大于高原腹地。(3)冰川变化的控制因素：a、温度对1956年至2010年祁连山区冰川的退缩特征和1963年至2010年我国西部冰川的退缩特征起到了控制性作用；b、祁连山区在消融区加速消融,温度增加起了重要贡献；而积累区消融减缓,降水增加起到了重要的补偿作用；c、祁连山东部冰川海拔较低、规模较小、大部分属于亚大陆型冰川,致使其在1990年至2010年间退缩速度快于西部的冰川；d、以温度为主导的多种因素叠加导致了在过去约半个世纪里,青藏高原周缘地区冰川退缩比例大于高原腹地。(4)冰川变化对温度变化的滞后性：a、祁连山地区冰川面积变化约滞后于年平均气温变化10年；b、全国冰川面积变化约滞后于年平均气温8至10年。(5)冰川变化预测：a、至2030年祁连山地区冰川面积相对于2010年,退缩比例为17%；b、至2050年祁连山地区冰川面积相对于2010年,退缩比例为37%；c、至2030年我国西部地区冰川面积相对于2010年,退缩比例为14%；b、至2050年我国西部地区冰川面积相对于2010年,退缩比例为29%。更多还原

【Abstract】 The Qilian Mountains are located in the arid and semiarid regions of northwestern China. It is an important ecological barrier, a transition zone between subcontinental glaciers and extreme continental glaciers, and the birthplace of modern glacier research in China. Studying glaciers in this area not only has a scientific significance, but also has ecological and social importance.Landsat TM, ETM+images were used with the help of digital elevation models and the first Chinese Glacier Inventory data to delineate the outlines of glaciers in the whole area in1990,2000and2010. Spatial distribution and variation characteristics of the glaciers were analyzed. Combined with our own results and previously published results, we calculated glacier area change information in China during the past half century. Then we analyzed the spatial and temporal characteristics of glacier area changes in China, and the trends in temperature, precipitation and freezing level from1961to2010. We also analyzed controlling factors of glacier area changes and time lag between glacier area changes and temperature changes. Based on the results of time lag analysis, we established an empirical model to predict glacier area changes. Finally, using the empirical model, we projected glacier area changes in the future. The main conclusions are as follows:(1) Characteristics of glacier distribution in the Qilian Mountains:the pattern of glacier area distribution with elevation was similar to the shape of normal distribution and the peak was at approximately5,000m; glaciers were distributed mainly in the north-facing aspect; glacier areas increased relative to their size class; more glaciers were distributed in the western portion than in the eastern portion of the study area.(2) Characteristics of glacier changes:glaciers shrank22.38±3%in the Qilian Mountains from1990to2010and the shrinkage accelerated during the second decade; glaciers shrank faster at lower elevations than at higher elevations; glacier shrinkage accelerated below5,000m and slowed down above5,000m; glaciers shrank faster in the south-facing aspect than in the north-facing aspects while maximum shrinkage occurred in the southwest aspect; smaller glaciers shrank faster than larger ones, and the shrinkage accelerated among all the size classes from2000to2010; glacier shrank faster in the eastern portion than in the western portion of the study area; glaciers shrank30.36%with an annual change rate of0.56%in the Qilian Mountains from1956to2010; glaciers shrank15.7%with an annual change rate of0.33%in China from1963to2010; glaciers shrank faster in the peripheral areas than internal areas of the Tibetan Plateau during the past half century.(3) Controlling factors of glacier area change:temperature was the main controlling factor of glacier area change in the Qilian Mountains during the period of1956-2010; temperature was the main controlling factor of glacier area change in China during the period of1963-2010; increasing temperature played an important role in accelerating glacier area shrinkage in ablation zones from2000to2010, while increasing precipitation compensated for melting caused by increasing temperature, resulting in reduced shrinkage in accumulation zones; since glaciers in the eastern portion of the Qilian Mountains were small, at low elevation and subcontinental type, they shrank faster than in the western portion; rising temperature accompanied by other factors caused faster glacier shrinkage in the peripheral areas than in the internal areas of the Tibetan Plateau in China during the past half century.(4) Time lag between glacier area change and temperature change:glacier area change lagged10years behind temperature change in the Qilian Mountains; glacier area change lagged between8to10years behind temperature change in China.(5) Prediction of glacier changes:glaciers in the Qilian Mountains are projected to shrink at an average rate of17%by2030and37%by2050compared to2010; glaciers in China are projected to shrink at an average rate of14%by2030and29%by2050compared to2010.更多还原