Observed linear trend in few surface weather elements over the Northwest Himalayas (NWH) during winter season

Abstract

Linear trends in few surface weather variables such as air temperatures (maximum temperature, minimum temperature), snow and rainy days, snowfall and rainfall amounts, rainfall contribution to seasonal total precipitation amount, seasonal snow cover depth and snow cover days (duration) are examined from winter-time observations at 11 stations located over the Northwest Himalayas (NWH). This study indicates that snowfall tends to show a decline in this region, while the rainfall tends to increase during the winter months. Seasonal snow cover depth and seasonal snow cover days also tend to show a decline over the NWH. Decrease in seasonal snow cover depth and duration have reduced the winter period in terms of availability of seasonal snow cover over the NWH during the last 2–3 decades. Other surface weather variables also exhibited significant temporal changes in recent decades. Observed trends in temperature and precipitation over the NWH in recent decades are also supported by long data series of temperature over the western Himalayas (WH), north mountain India (NMI) rainfall data and reanalysis products.