Snow cover monitoring in Baspa basin using IRS WiFS data

Abstract

Seasonal snow cover monitoring was carried out in the Baspa river basin using IRS 1C, 1D and P3 WiFS data. In the study, a period between October and June for years starting from 1996-97 to 2001-2002 was used. A total of 57 scenes were analyzed.  Systematic analysis of changes in snow cover suggests that extent of snow cover in early winter, i.e. October to January of 2001-2002 and mid December to mid February 2000-2001 is substantially lower than year 1997-98 and 1998-99.  This low snow cover is caused due to lower snowfall in the early part of winter and abnormally high temperature.  On the other hand snow accumulation pattern in year 2000-2001 is completely different. Overall snow cover is very high in the month of November-December. However, from the beginning of December snow cover started to reduce and this trend continues up to middle of February. The melting of snow cover in the peak of winter, i.e. January and February is very unusual observation. In addition, overall snow extent is almost 30 % less than average of four years. This has also affected snow depletion pattern, for example, at the beginning of May 1998 approximately 85 percent basin was covered by snow and in the year 1999 only 74 % of basin was covered by snow. Melting and retreat of snow cover was analyzed using depletion curves. Snow depletion curve suggests an altitude zone between 3000 to 3600 m is free of snow by beginning of May and altitude between 3600 and 4200 m is cleared by beginning of June and higher attitude zone between 4200 to 4800 m is cleared by middle of June.