基于多源遥感数据的乌鲁木齐河源1号冰川平衡线高度研究

Study on the Equilibrium Line Altitude Based on Multi-source Remote-Sensing Data of Urumqi Glacier No.1 in Tianshan

以我国天山乌鲁木齐河源1号冰川(以下简称1号冰川)为例,基于Landsat TM/ETM/OLI和Sentinel-2A MSI数据,利用归一化差异积雪指数(NDSI)和阈值法提取该冰川2002-2015年的平衡线高度,并利用站点实测的冰川ELA数据和气象数据对提取的平衡线高度进行了验证。结果表明,2002-2015年遥感获取的平衡线高度呈总体上升的趋势,与实测的平衡线具有高度相关性(r=0.9);ELA与年物质平衡序列高度相关,物质平衡波动的平均解释率可高达69%;与气象要素(温度和降水)年际变化的相关性也很高,约有59%的冰川ELA变化可以用夏季气温和降水来解释。因此,利用遥感数据可以提取高精度的冰川平衡线高度数据,对无站点数据冰川的平衡线高度以及物质平衡研究具有一定的借鉴意义。

Taking the Urumqi Glacier No.1 in Tianshan in China as an example,based on Landsat and Sentinel-2 A MSI images,the glacier equilibrium line altitude was derived from the Normalized Difference Snow Index(NDSI)method and threshold setting degree.ELA was verified by using the measured glacier ELA data and meteorological data.The results showed that during 2002-2015,the overall trend of ELA derived from remote-sensing data was generally increasing,which was highly correlated with the ELA obtained from ground measurements(r=0.9).ELA had a high correlation with the annual mass balance sequence,and the average interpretation rate of the mass balance fluctuation could be as high as 69%;correlation with the inter-annual variability of meteorological elements(temperature and precipitation)was also high,and about 59%of glacial ELA changes could be explained by summer temperature.Therefore,remote sensing data can be used to extract the glacier equilibrium line altitude,and then used to estimate the equilibrium line altitude and mass balance of glaciers where no ground measurements exist,it has certain reference significance.