亚大陆型小冰川厚度估算模型研究-以祁连山冷龙岭冰川为例

China has a most mountain glaciers in the global middle and low-latitude. As the climate continues to warm, most mountain glaciers are facing more intense negative balance. Changes in glacier volume are influencing the river runoff and water resource. The accurate estimate of the glacier thickness is the key factor in glacier volume estimate and predicts water resources and other issues. Up to now, there is not a more accurate method to estimate the thickness of the glacier in Tibetan Plateau. The glacier size is relatively small just like the most glaciers in Tibetan Plateau. Furthermore, the glaciers in this region are convenient for observing and measuring. Therefore, the glaciers in Lenglongling Mountains are selected to research. The aerial topographic maps and high-resolution remote sensing images were utilized based on the remote sensing and GIS technology. The Volume-Area scaling, slope-dependent thickness estimations, glacier bed topography and glacier velocity-thickness relationship methods were adopted to estimate the glacier thickness. Compared with the GPR measured glacier thickness, the most suitable estimate glacier thickness methods for the study area can be selected, which can provide the basic data for the calculation of glacier volume and water resource in the study area. Furthermore, validate and forecast data for the changes of river runoff in the Tibetan Plateau and the low-latitude glaciers, which plays a significance meaning in understanding the mechanism of glacier response to climate change.

中国是全球中低纬度山地冰川面积最大的国家，其冰川厚度的准确估算是冰川储量、河川径流、水资源及其未来变化预测的关键，也是冰川水资源保护利用和未来水资源安全利用的基础。但目前，尚缺乏针对不同规模，不同地区冰川厚度估算方法的系统评估和对比研究。祁连山东段冷龙岭地区冰川属于亚大陆型小冰川，易于获得雷达实测的厚度数据，本项目拟以冷龙岭现代冰川为研究对象，以冰川雷达实测厚度资料为基础，结合航测地形图、高分辨率遥感影像，利用遥感和GIS技术，对四种冰川厚度估算方法进行参数改进，综合分析提出适合亚大陆型小冰川厚度估算的准确方法，查明区域冰储量。本研究可提高区域尺度上冰川储量的估算精度，为亚大陆型小冰川储量估算提供方法，提升整个青藏高原冰川储量和水资源未来变化趋势预估的可靠性。

随着全球气候变化，青藏高原大部分冰川都面临着不同程度的退缩。祁连山冷龙岭地区冰川融水作为河西干旱区重要的水资源，近几十年来，冷龙岭地区冰川退缩剧烈，威胁着当地的水资源利用与社会经济发展。本研究基于多源遥感影像和数字高程模型，获得了冷龙岭地区近几十年冰川面积和储量变化，为了对比不同类型冰川对气候变化的响应，我们还获得了贡嘎山和西昆仑主峰地区的冰川变化。结果发现，1972年至2016年，冷龙岭地区冰川总面积减少41.1km2，占第一次冰川编目时期面积39.8%，冰川的平均退缩速率为0.93 km a-1；1972-2016年间，冰川区平均减薄量为18.7±1.2m，减薄速率为0.43±0.03 m a-1。通过对比发现，冷龙岭地区冰川退缩速率较快。此外，基于宁缠河1号冰川多年实地监测资料，构建了冰川表面物质平衡模型，评估了冷龙岭地区冰川变化对水资源的影响。结果显示在冷龙岭地区九条岭流域，冰川面积占整个流域面积1.4%。结果显示，在1972-2013年间，冰川融水占河川径流的4.6%，而在一些特别干旱的年份，冰川融水占河川径流的8%，冰川融水对河川径流起着一定的调节作用。最后，基于遥感影像，通过影像互相关法获得冷龙岭地区冰川表面运动速度，进而利用冰川厚度估算模型，估算冷龙岭地区冰川储量，大约为2974.3m3。本研究可为河西地区冰川变化对水资源估算提供重要基础数据。