Spatio-Temporal Analysis of Early Twenty-First Century Areal Changes in the Kabul River Basin Cryosphere

Abstract

Climate change is a common concern globally and the Kabul River Basin, a transboundary basin between Pakistan and Afghanistan, is no exception. Rising temperatures cause snow and glaciers to melt rapidly, which increases the variability of river flows that may affect the water resource management between the two countries. For this purpose, it is necessary to study snow and glaciers, the main source of river flow. The goal of this research is to assess and analyze the basin-scale and elevation-zonal variation in the areal extent of snow and glacier cover for the years 2001–2016, on daily, monthly, seasonal and yearly basis. The basin was distributed into eight elevation zones; and snow cover for the whole basin and each elevation zone was then extracted by utilizing the Moderate Resolution Imaging Spectroradiometer (MODIS), Onboard TERRA Satellite, 8-daily, 500 m resolution images. As per average climatology of the basin, snow cover is minimum in August because of higher summer temperatures and maximum in February owing to lower winter temperatures and higher westerly precipitation in solid form. Based on the basin-scale analysis of changes in the daily snow-covered areal extents, it is found that snow cover significantly increases in the three lowest elevation zones, whereas in the mid elevation zones (Zone 4 and 5) and the highest elevation zone (Zone 8) a negligible decreasing trend is found. Moreover, non-significant but decreasing trend in Zone 8 may hint either at decrease in solid precipitation in the high elevation region or a slight retreat of the glaciers which may become significant in the coming years. In addition, there is a significant decreasing trend of snow covered area in Zones 6 and 7 which gives a similar indication. Our seasonal and annual analysis indicates that there is an overall slight increasing trend in the basin for all analyzed seasons and also on annual basis. The results concluded that a detailed hydro-climate modeling analysis should be carried out for this basin to find the changes in water availability under the future climate scenarios.