Mapping Snowmelt Progression in the Upper Indus Basin With Synthetic Aperture Radar
Mapping Snowmelt Progression in the Upper Indus Basin With Synthetic Aperture Radar
复制标题
DOI：
10.3389/feart.2019.00318
复制
发表时间：
2020-01
期刊：
影响因子：
--
通讯作者：
J. Lund;R. Forster;S. Rupper;E. Deeb;H. Marshall;M. Hashmi;E. Burgess
中科院分区：
文献类型：
--
作者：
J. Lund;R. Forster;S. Rupper;E. Deeb;H. Marshall;M. Hashmi;E. Burgess
对于生活在巴基斯坦、印度、中国和阿富汗的数百万人来说，印度河是粮食安全、生态系统服务、水电和经济的重要资源。来自高海拔喜马拉雅山、喀喇昆仑山脉和兴都库什山脉的冰川和融雪是印度河上游盆地 (UIB) 流量的最大驱动因素，并对印度河流量做出了重大贡献。复杂的气候和地形，加上这些崎岖山脉的实地研究和气象测量的挑战，在预测季节性径流以及冰冻圈对气候变化的响应方面引起了显着的不确定性。在这里，我们利用Sentinel-1合成孔径雷达（SAR）图像来跟踪2015年至2018年巴基斯坦喀喇昆仑山脉希格尔流域湿雪消融季节的发展。我们利用适当的局部图像采集时间来突出湿雪雷达指示的日间差异，并检查2015年、2017年和2018年消融季节雷达日间差异的空间和时间背景。每个消融季节的雷达分类显示了空间和时间模式，表明干燥的冬季积雪正在经历昼夜表面融化-再冻结循环，过渡到白天和晚上都保持湿润的表面积雪，最后融化后出现无雪状态。每日不同的 SAR 信号可能有助于了解融化前重要的积雪能量平衡过程，这可以为偏远高山流域的冰川质量平衡建模和径流预测提供有用的约束。
The Indus River is a vital resource for food security, ecosystem services, hydropower, and economy for millions of people living in Pakistan, India, China, and Afghanistan. Glacier and snowmelt from the high altitude Himalaya, Karakoram, and Hindu Kush mountain ranges are the largest drivers of discharge in the upper Indus Basin (UIB), and contribute significantly to Indus flows. Complex climatology and topography, coupled with the challenges of field study and meteorological measurement in these rugged ranges, elicit notable uncertainties in predicting seasonal runoff as well as cryospheric response to changes in climate. Here we utilize Sentinel-1 synthetic aperture radar (SAR) imagery to track ablation season development of wet snow in the Shigar Watershed of the Karakoram Mountains in Pakistan from 2015 to 2018. We exploit opportune local image acquisition times to highlight diurnal differences in radar indications of wet snow, and examine the spatial and temporal contexts of radar diurnal differences for 2015, 2017, and 2018 ablation seasons. Radar classifications for each ablation season show spatial and temporal patterns that indicate a dry winter snowpack undergoing diurnal surface melt-refreeze cycles, transitioning to surface snow that remains wet both day and night, and finally snow free conditions following melt out. Diurnally differing SAR signals may offer insights into important snowpack energy balance processes that precede melt out, which could provide useful constraints for both glacier mass balance modeling and runoff forecasting in remote alpine watersheds.