I need to generate seasonal snow cover area for the past 50 years based on available Snow cover products i.e) Modis, AVHRR, AWIFS data comparing with precipitation and temperature.
As you for sure know there exist several datasets from satellite and ground-based data that you can combine and check depending on your specific need.
Anyway, a possible answer to your question could come from reading the following literature:
Bormann, K. J., M. F. McCabe, and J. P. Evans, 2012: Satellite based observations for seasonal snow cover detection and characterisation in Australia. Rem. Sens. Environ., 123, 57-71.
Nolin, A. W., 2011: Recent advances in remote sensing of seasonal snow, J. Glaciol., 56, 1141-1150.
Notarnicola, C., M. Duguay, N. Moelg, T. Schellenberger, A. Tetzlaff, R. Monsorno, A. Costa, C. Steurer, and M. Zebisch, 2013: Snow Cover Maps from MODIS Images at 250 m Resolution, Part 1: Algorithm Description. Remote Sens., 5, 110-126.
Sirguey, P., R. Mathieu, and Y. Arnaud, 2009: Subpixel monitoring of the seasonal snow cover with MODIS at 250 m spatial resolution in the Southern Alps of New Zealand: Methodology and accuracy assessment. Rem. Sens. Environ., 113, 160-181.