Mass balance and morphological changes of Dokriani Glacier (1992–2013), Garhwal Himalaya, India

Glacier mass balance measurements is an important element in understanding the processes of accumulation and ablation over a period of time that depend on the climatic conditions and geometry of the glacier. Glacier change can be through field, ground and aerial photographic measurements and high-resolution remote sensing at local, regional and global scale. In this study we presents a long time series ground observations of the mass balance and length change of Dokriani Glacier for the period 1992–2013. A medium sized glacier (6.6 km2) characterised by large accumulation area with narrowing ablation is located in the monsoon dominated zone of Central Himalaya, India. The spatial variability in the mass balance gradient profile of the two different study periods (i.e. 1992-2000 and 2007–2013) show consistency, but has shift upwards in the recent year. The glacier has higher value of AARn (67%) which attributed to a flat and broader accumulation area. Although, having a larger accumulation area compared to the ablation area, the glacier has strong mass wasting with an average annual ablation of −1.85 m w. e. a−1 as compared to the residual average annual accumulation of 0.44 m w. e. a−1. The recession rate of 21 m a−1 during 2007–2013 slightly higher than the retreat rate of 18 m a−1 during 1992–2000 and 16 m a−1 during 2000–2007. In addition, the state of Dokriani Glacier, based on accumulation-area ratio (i.e. AARn and AAR0) suggests that glacier in disequilibrium having decrease its accumulation area. The progressive retreat rate and continuous negative mass balance of the glacier affects its extension and volume. The overall morphological changes that includes reduction ∼14% of total glacier area and enhancement of debris over the ablation zone (∼4%) during the study period is significant. The present study is a part of long ground based observations on retreat of glacier in the Himalayan region.