Recent changes of two parts of Kolahoi Glacier and its controlling factors in Kashmir basin, western Himalaya

Abstract Kolahoi Glacier is a mountain glacier (11 ± 0.11 km 2 ) distributed between Lidder and Sind catchments of Kashmir basin, western Himalaya. In this study, using semi-automated approach based on ASTER GDEM, the mapping of ice/water divide was carried out and subsequently the glacier was separated into two units designated as Kolahoi Glacier 1 (K1) and Kolahoi Glacier 2 (K2) draining into Lidder and Sind catchments respectively. Using OLI Landsat 8 satellite data (2016), the total area of K1 and K2 units were estimated to be 8.09 ± 0.11 km 2 and 2.91 ± 0.07 km 2 with an average length of 4.98 ± 0.05 km and 3.53 ± 0.04 km. From 1979 to 2016, the study indicated an area loss of 11.66 ± 4.3% (30 ± 0.86) m 2 /year for K1 and 18.7 ± 4.2% (19 ± 1.16) m 2 /year for K2 with a combined loss of 13.63 ± 2.3% (1.74 ± 0.02) km 2 at a rate of 48 ± 0.63 m 2 /year for the whole Kolahoi Glacier. Over the same time, the length of K1 and K2 has receded by 780 ± 19 m (22 ± 0.53 m/year) and 390 ± 28 m (11 ± 0.77 m/year). A heterogeneous pattern of area loss and recession is exhibited by K1 and K2 units of the Kolahoi Glacier. The K1 exhibits a higher length and lower area loss compared to K2 which displays a lower length and higher area loss. The disparity in area and length changes of the K1 and K2 units of the Kolahoi Glacier are strongly influenced by the topographic configuration and other local factors. For example, the higher frontal recession of K1 is controlled predominantly by its lower frontal width-length ratio (0.45) and large altitude range (3699–5051 m a.s.l.). Contrary to it, the higher area loss of K2 is predominantly controlled by its steep mean slope, southerly mean aspect, higher mean solar radiation and debris free nature. Noticeably a steep gradient of the frontal termini of K1 and K2 resulted in its higher retreat during a recent decade of 2001–2016. Nevertheless, a higher shift in ELA (~ 170 ± 1.7 m) and lower mean accumulation area ratio (0.36%) of K1 indicated that it is more sensitive to climatic variations than K2.