Correlations of Stream Flow and Climatic Variables for a Large Glacierized Himalayan Basin

Abstract

Streamflow represents the integrated response of a watershed to climatic variables, particularly precipitation and air temperature. In this study, relationships between discharge and hydro meteorological parameters near the snout of Gangotri Glacier were investigated. The auto correlations and multi day influence of temperature and rainfall on discharge can provide valuable information about the Glacier response which can be helpful for estimating discharge in data scarce regions. The data for eight continuous ablation seasons (2000-2007) were used investigating correlations, lag cross correlations and multivariate regression analysis between daily mean discharge, daily mean temperature and daily rainfall, whereas last four years data (2008-2011) was used to simulate the daily discharge from the established relations. Snowmelt discharge varies during the rise in the annual temperature cycle in response to the combination of temperature variation and the amount of water held in the evolving snowpack. The discharge and temperature is highly auto correlated. It was found that discharge of a particular day (Q i ) is well represented by the regression equation having Q i-1 , T i , and R i . Such developed regression equation can be used for computing discharge once its input variables are available. The regression equation developed using the eight year data i.e . Q i = 2.962 + 1.011Q i-1 - 0.422T i + 0.203R i is used for forecasting of discharge. For all the years discharge was computed with high accuracy (R 2 - 0.93).