Time series analysis of hydrometeorological data for the characterization of meltwater storage in glaciers Garhwal Himalaya

Abstract Integrated long-term hydro-meteorological investigations are not frequently available in Indian Himalaya Region (IHR), especially near the glacier terminus. Collection and analysis of integrated hydro-meteorological observations help in understanding the weather conditions, glacier melting pattern and other flow-generation processes. Changes in local precipitation, snow cover pattern and glacier storage are likely to affect discharge in terms of volume and its variability. Hence, there is a need to establish a linkage between glacio-hydrological processes with the climate. The current study involves a time series analysis of hydro-meteorological records collected near the terminus of some glaciers in Garhwal Himalaya for available consecutive ablation seasons. The time series analysis has been utilized for determining correlations and Auto-correlation (ACF). Changes in correlations between meltwater discharge and meteorological variables are discussed. The analysis suggests a very high discharge auto-correlation for each year and the combined data series of individual glaciers. The substantial storage of meltwater in the glacier body and its delayed response to the runoff is attributed to the high dependency of a particular day’s discharge on its previous day’s discharge. Variations in the physical features of the glacier, weather conditions, precipitation and its distribution with time over the basin account for changes in correlations. A comparison of correlations between discharge and temperature, and discharge and rain shows that temperature has a better correlation with discharge for all the years. In the early stages of the ablation period, poor drainage networks and stronger storage characteristics are observed in the glaciers due to the presence of seasonal snow cover. The impact of such meltwater storage and delaying characteristics of glaciers on hydropower projects being planned and/or developed on glacier-fed streams in Garhwal Himalaya are highlighted.