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| 青藏高原昆仑山木孜塔格冰川反照率变化特征及其与粉尘的关系 | |
| 其他题名 | Spatiotemporal variations and the relationship between the albedo and the dust on Tibetan Plateau Kunlun Mountains |
| 毛瑞娟 | |
| 出版年 | 2013 |
| 学位类型 | 硕士 |
| 导师 | 王宁练 |
| 学位授予单位 | 中国科学院大学 |
| 中文摘要 | 冰川反照率变化对融水径流以及气候变化的影响，已成为国际冰雪界研究的焦点问题之一。冰川融水为中国西部生态经济的发展提供了宝贵的淡水资源。在全球变暖的大背景下，中国西部冰川出现不同程度的退缩趋势，评估冰川变化对水资源的影响已成为我国冰冻圈科学研究的热点。冰川反照率发生变化，会导致冰川接收到太阳净辐射量发生变化，净辐射为冰川消融提供能量，因此，冰川上反照率变化会导致冰川消融状况发生变化，影响到冰川水文过程。因此，面对未来水资源危机和我国西部可持续发展，有必要开展对冰雪反照率时空变化特征和影响因素的研究，探讨地形、气候等因素对其变化的影响，为冰川物质平衡和寒区水资源变化研究提供科学依据。卫星遥感资料因其容易获取，时间跨度长，反照率反演技术相对成熟，成为研究冰川表面反照率时空变化的有效数据源。 本研究以landsat TM/ETM+影像反照率反演结果、MOD10A1逐日反照率产品为主要数据源，首先基于实测数据得到landsat TM/ETM+影像反照率反演结果，而后用landsat TM/ETM+影像反照率对MOD10A1逐日反照率产品进行验证，最后利用这两种遥感数据资料对木孜塔格冰川表面反照率的时空变化特征进行分析，并探讨了反照率与粉尘的关系和对反照率影响因素进行了综述。主要结论如下： （1）反照率遥感产品的精度验证 本文通过木孜塔格冰川短时间内实测反照率数据建立反射率窄波段向宽波段转换的公式将landsat TM/ETM+影像反演的反射率转成反照率，这样大大提高了landsat TM/ETM+反照率反演精度，然后将landsat TM/ETM+影像反照率上升尺度到MODIS像元尺度上，以此对MOD10A1反照率产品的数据精度进行验证。结果表明，与同时期Landsat影像反照率反演结果的相关系数均能达到0.9以上，故该产品能够适用于冰川反照率时空变化特征研究。 （2）木孜塔格冰川反照率空间变化特征 本文根据夏季成像的Landsat TM影像反照率反演结果分析木孜塔格表面反照率在夏季的空间分布特征。结果表明，冰川表面反照率具有明显的空间变化特征，以100米为间隔，划分为若干个海拔高度带，并对各个高度带的反照率进行均值统计，其数值介于0.508-0.637，总体上随着海拔升高而增大，在海拔6000m以上，由于有裸岩的存在，以及较大坡度、坡向产生遮蔽效应导致反照率开始下降。 （3）木孜塔格冰川反照率时间变化特征 从年际变化上看，在2000-2009年间木孜塔格冰川反照率年际变化波动较大，并呈微弱的上升趋势，速率约为0.0025?a-1 ，积累区、消融区反照率也有逐年上升的趋势，速率分别为0.0019?a-1 、0.0034?a-1。通过与气温、降水资料分析发现，反照率的年际变化主要与夏季温度和年降水量变化相关性较高。 从季节变化上看，冰川表面反照率的季节变化特征较为一致，即在秋冬季反照率最大，经由冬春季逐渐减少，到夏季反照率达到最小。有些年份出现异常，这与气温、降水异常和污化物有关。并发现夏季反照率年际变化主要与受夏季温度影响较大，与夏季降水的相关性较小。 （4）反照率与粉尘的关系 沙尘天气过程、人类活动所产生的气溶胶、冰雪消融所导致的粉尘物质在表面的积累过程等，均可造成冰雪反照率的变化。木孜塔格冰川北依塔里木盆地，塔里木盆地拥有我国第一大流动沙漠-塔克拉玛干沙漠，是我国沙尘暴天气最为频发的地区之一。尘埃含量对高原北部冰川反照率影响较大，特别是中国西北春季沙尘高发季节。本文在分析反照率其他影响因素的基础上，特别就冰雪中粉尘第一大流动沙漠-塔克拉玛干沙漠，是我国沙尘暴天气最为频发的地区含量对反照率的影响进行分析，结果为反照率与微粒个数呈现负相关关系，相关系数r=-0.664，显著性水平在0.01内。本研究由于粉尘样品有限，只简单初步探讨了反照率与粉尘的关系。由于木孜塔格钻取的冰芯，微粒测量结果已经完成，但是定年结果还没完成，在下一步工作中，可以通过反照率长时间序列的年际变化结合冰芯中各年层测量的微粒数据，定量的分析反照率与微粒的关系。 |
| 英文摘要 | Glacier albedo changing meltwater runoff and climate change , has become the focal point of one of the International Ice and Snow. Glacial runoff provides a sustaining freshwater resource for the eco-economic development in western China. The glaciers in western China have been retreating continuously under the background of global warming in recent decades. Glacier albedo is a critical parameter which controls the process of surface energy budget, with the significant spatiotemporal variations, the accuracy of which is the key factor that restricts the development of a distributed glacier energy and mass balance model. Glacier albedo change will cause glaciers to changes in net solar radiation received , net radiation to provide energy for the melting of glaciers , glacier albedo change will lead to change melting of glaciers and affect glacier hydrological processes. In the face of the water crisis and sustainable development in western China, it is necessary to carry out the study of snow albedo spatial and temporal variation characteristics and influencing factors .Remote sensing sensors, acquiring the images over entire glacier regions at regular intervals, have provided the convenient and effective datasets to the research on the glacier albedo for the long period. In this research, the albedo datasets retrieved from Landsat TM/ETM+ images and MOD10A1 daily albedo product as the main date source, the first two albedo remote sensing data accuracy verification on Muztagh glacier , and then based on these two remote sensing data temporal and spatial variation of surface albedo analysis Finally, we discuss the relationship between the albedo and dust .The main conclusions can be shown as following. 1) In this paper, Muztagh glacier albedo measured reflectance data to establish a narrow band to wide-band conversion formulas. It greatly improves the Landsat TM / ETM + albedo retrieval accuracy. The accuracy of MOD10A1 daily albedo product has been assessed using the retrieved albedo values from Landsat TM images, by the method of spatial scale transformation. The results show the correlation coefficients between MOD10A1 albedo values and the derived albedo values from Landsat images on the different glaciers are all above 0.9, Thus, the accuracy of Landsat-derived albedo can be applied to the research on the spatial variation of albedo on a single glacier. 2) Surface albedo on a single glacier during the ablation period veries significantly in spatial, the values of which range from 0.508 to 0.637. albedo on the Muztag glacier increases with altitude, ranging from 0.508-0.637,Overall aldedo increases with altitude, 5950m above sea level , due to the existence of bare rock albedo began to decline. 3) During the period of 2000-2009, albedo of the glacier appeared an obvious fluctuation, and increased slowly, with a rate of 0.0025a-1. High , low altitude albedo also an increasing trend , the rates were 0.0019 ? a-1 , 0.0034 ? a-1 . Although global warming gradually , but due to Muztagh glaciers at higher elevations , the global temperature rise is small glaciers may forward trend . Judging from the seasonal variation, Seasonal variations of performance is more consistent. Albedo maximum in the autumn and winter, Gradually reduced through the winter and spring , the summer minimum albedo 4) Dust weather process , aerosols generated by human activity , caused by the melting ice and snow dust material in the surface of the accumulation process , can be caused by changes in the ice and snow albedo . Albedo and particle number are negatively related , that the correlation coefficient r = -0.664 , P <0.01 . This study was to explore the relationship between albedo and dust. In the next step , The quantitative analysis of the relationship between the albedo and the fine particles . |
| 中文关键词 | 反照率 ; 昆仑山木孜塔格冰川 ; 遥感反演 ; 时空变化 ; 粉尘 |
| 英文关键词 | albedo Kunlun Mountains Muztagh glacier remote sensing retrieval temporal and spatial variation dust |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源学科分类 | 自然地理学 |
| 来源机构 | 中国科学院西北生态环境资源研究院 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/287242 |
| 推荐引用方式 GB/T 7714 | 毛瑞娟. 青藏高原昆仑山木孜塔格冰川反照率变化特征及其与粉尘的关系[D]. 中国科学院大学,2013. |
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