A statistical approach to estimate equilibrium line altitude (ELA) and its trend analysis on Naradu Glacier, Himachal Himalaya

Abstract

The Equilibrium Line Altitude (ELA) is a significant indicator of the changing climate and glacial dynamics. Trend of equilibrium line altitude has been analysed for the period of 1979/80 to 2012/13 in Naradu Valley, western Himalaya. The clear effect of valley’s increased temperature can be seen on ELA trend. The temperature, precipitation and few years ELA data have been used as an input parameters to develop a multiple linear regression equation. By using the developed equation, ELA of thirty four years has been reconstructed. Mann-Kendall and Spearman Rank Correlation tests have been applied to analyse the significance level. The reconstructed ELA data shows, a significant positive trend with a magnitude of 96.73 m for the entire period. The monthly and seasonal analysis shows that the trend was positive. The magnitude of increased seasonal ELA was 4.02 m/year, 3.24 m/year, 2.84 m/year, and 2.04 m/year for post-monsoon, pre-monsoon, winter and monsoon respectively.