Spaceborne Satellite for Snow Cover and Hydrological Characteristic of the Gilgit River Basin, Hindukush⁻Karakoram Mountains, Pakistan.

Dostdar Hussain,Chung-Yen Kuo,Bulbul Jan,Huan-Chin Kao,Abdul Hameed,Moslem Imani,Kuo-Hsin Tseng,Wen-Hau Lan,Nasir Abbas

doi:10.3390/s19030531

Abstract

The Indus River, which flows through China, India, and Pakistan, is mainly fed by melting snow and glaciers that are spread across the Hindukush–Karakoram–Himalaya Mountains. The downstream population of the Indus Plain heavily relies on this water resource for drinking, irrigation, and hydropower generation. Therefore, its river runoff variability must be properly monitored. Gilgit Basin, the northwestern part of the Upper Indus Basin, is selected for studying cryosphere dynamics and its implications on river runoff. In this study, 8-day snow products (MOD10A2) of moderate resolution imaging spectroradiometer, from 2001 to 2015 are selected to access the snow-covered area (SCA) in the catchment. A non-parametric Mann–Kendall test and Sen’s slope are calculated to assess whether a significant trend exists in the SCA time series data. Then, data from ground observatories for 1995–2013 are analyzed to demonstrate annual and seasonal signals in air temperature and precipitation. Results indicate that the annual and seasonal mean of SCA show a non-significant decreasing trend, but the autumn season shows a statistically significant decreasing SCA with a slope of −198.36 km2/year. The annual mean temperature and precipitation show an increasing trend with highest values of slope 0.05 °C/year and 14.98 mm/year, respectively. Furthermore, Pearson correlation coefficients are calculated for the hydro-meteorological data to demonstrate any possible relationship. The SCA is affirmed to have a highly negative correlation with mean temperature and runoff. Meanwhile, SCA has a very weak relation with precipitation data. The Pearson correlation coefficient between SCA and runoff is −0.82, which confirms that the Gilgit River runoff largely depends on the melting of snow cover rather than direct precipitation. The study indicates that the SCA slightly decreased for the study period, which depicts a possible impact of global warming on this mountainous region.

Highlights

The Asian high mountain ranges of Himalaya, Karakoram, and Hindukush (HKH) are collectively termed the “third pole of our planet” [1]
The red dotted dotted line shows the trend while the blue solid line shows snow-covered area (SCA) (%) variability
moderate resolution imaging spectroradiometer (MODIS) snow cover for the study period indicates that the SCA in the Gilgit River Basin has a slightly decreasing trend, the trend is not statistically significant

Summary

Introduction

The Asian high mountain ranges of Himalaya, Karakoram, and Hindukush (HKH) are collectively termed the “third pole of our planet” [1]. These mountains, which provide freshwater to 1.3 billion people in the Indo–Gangatic plains, are called the “Water Towers of Asia” [2]. The river subsequently runs through northern areas of Pakistan and falls into the Arabian Sea. Snow and ice melts, the main sources of the Indus River, play irreplaceable roles in Pakistan’s economy [3]

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