Datasets on multiparameter glacier change dynamics for the Jankar Chhu Watershed, Lahaul Himalaya, India

Characterization of glacier changes in the surface area, terminus, equilibrium line altitude (ELA), elevation, and velocity was worked out for the Jankar Chhu Watershed (JCW) of Lahaul Himalaya using freely available satellite remote sensing data and the limited number of field observations. We studied changes using Corona (1971), Landsat (1993‒2017), Sentinel 2A (2016), the SRTM Digital Elevation Model (DEM; 2000), and the global TanDEM‒X DEM (2014). Our results showed that changes in glacier area (‒14.7 ± 4.3 km²), terminus (‒4.7 ± 0.4 m a¯¹), and ELA (~ 20 m rise) between 1971 and 2016 are smaller than previously reported. Glacier lake area increased by ~0.3 km² during 1971‒2016. An intricate pattern of mass changes across the JCW was observed, with surface lowering on an average of ‒0.7 ± 0.4 m a¯¹ which equates to a geodetic mass balance of ‒0.6 ± 0.4 m w.e. a¯¹ during 2000‒14. The computed glacier surface velocities (1971‒2017) reveal nearly stagnant debris-covered ablation zone but the dynamically active main trunk. The present study provides valuable insights into the recent multiparameter glacier variations, which are of critical importance to assess the future glacier dynamics on a regional scale in areas like the present one.

本研究基于公开免费的卫星遥感数据与有限的实地观测资料，对拉霍尔喜马拉雅（Lahaul Himalaya）地区的江卡尔曲流域（Jankar Chhu Watershed, JCW）内冰川的表面积、末端位置、平衡线高度（equilibrium line altitude, ELA）、高程以及运动速度的变化特征开展了系统刻画与分析。本次研究所用数据源涵盖1971年的Corona影像、1993—2017年的Landsat系列影像、2016年的Sentinel 2A影像、2000年的航天飞机雷达地形测绘任务数字高程模型（SRTM Digital Elevation Model, DEM）以及2014年的全球TanDEM-X DEM。研究结果表明，1971至2016年间该流域冰川面积变化量为-14.7±4.3 km²、冰川末端退缩速率为-4.7±0.4 m·a⁻¹，平衡线高度上升约20米，上述变化幅度均小于既往研究的报道结果。1971—2016年间，流域内冰川湖面积增加约0.3 km²。2000—2014年间，江卡尔曲流域内冰川物质变化呈现复杂的空间分布格局：冰川表面平均高程降低速率为-0.7±0.4 m·a⁻¹，对应大地测量物质平衡为-0.6±0.4 米水当量·a⁻¹。通过反演得到的1971—2017年冰川表面运动速度显示，覆盖冰碛物的消融区几乎处于停滞状态，但冰川主主干段仍处于活跃的动态运动状态。本研究为近期多参数冰川变化特征提供了极具价值的科学认知，对于评估类似本研究区域的区域性未来冰川动力学变化具有关键的参考意义。