• A Ganju

      Articles written in Journal of Earth System Science

    • Mountain range specific analog weather forecast model for northwest Himalaya in India

      D Singh A Ganju

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      Mountain range specific analog weather forecast model is developed utilizing surface weather observations of reference stations in each mountain range in northwest Himalaya (NW-Himalaya).The model searches past similar cases from historical dataset of reference observatory in each mountain range based on current situation.The searched past similar cases of each mountain range are used to draw weather forecast for that mountain range in operational weather forecasting mode, three days in advance.The developed analog weather forecast model is tested with the independent dataset of more than 717 days (542 days for Pir Panjal range in HP)of the past 4 winters (2003 –2004 to 2006 –2007).Independent test results are reasonably good and suggest that there is some possibility of forecasting weather in operational weather forecasting mode employing analog method over different mountain ranges in NW-Himalaya.Significant difference in overall accuracy of the model is found for prediction of snow day and no-snow day over different mountain ranges, when weather is predicted under snow day and no-snow day weather forecast categories respectively.In the same mountain range,signi ficant difference is also found in overall accuracy of the model for prediction of snow day and no-snow day for different areas.This can be attributed to their geographical position and topographical differences.The analog weather forecast model performs better than persistence and climatological forecast for day-1 predictions for all the mountain ranges except Karakoram range in NW-Himalaya.The developed analog weather forecast model may help as a guidance tool for forecasting weather in operational weather forecasting mode in different mountain ranges in NW-Himalaya.

    • Monitoring of Gangotri glacier using remote sensing and ground observations

      H S Negi N K Thakur A Ganju Snehmani

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      In this study, Gangotri glacier was monitored using Indian Remote Sensing (IRS) LISS-III sensor data in combination with field collected snow-meteorological data for a period of seven years (2001–2008). An overall decreasing trend in the areal extent of seasonal snow cover area (SCA) was observed. An upward shifting trend of wet snow line was observed in the beginning of melt period, i.e., in May and dominant wet snow conditions were observed between May and October. Snow meteorological parameters collected in the Gangotri sub-basin suggest reduction in fresh snowfall amount during winter, increase in rainfall amount during summer, decrease in snowfall days, increase in rainfall days and rising trend of average temperature. The prevailing wet snow condition on glacier has caused scouring of slopes which led the excessive soil/debris deposition on the glacier surface. This was observed as one of the major factor for activating fast melting and affecting the glacier health significantly. Apart from climatic conditions, terrain factors were observed for changing the glacio-morphology. The significant changes on the glacier surface were observed in the regions of abrupt slope change. The above factors affecting the Gangotri glacier health were also validated using high resolution satellite imageries and field visit. A deglaciation of 6% in overall area of Gangotri glacier was observed between the years 1962 and 2006.

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