Formation of snow cover trends in October over the Tibetan plateau during 1980-2019

The present study investigated the snow cover trend and its causes in October over the Tibetan Plateau during 1980-2019. Both the snow cover and snow cover increment show a significant increasing trend in October over the central-eastern Tibetan Plateau due to the increase in snow accumulation. The increasing precipitation plays a dominant role in the snow accumulation increase. The direct contribution of rising temperature to the snow accumulation trend is small. However, the increasing precipitation is attributed to the combined effect of evaporation and the thermodynamic contribution associated with the change in specific humidity, both of which are associated with the increasing temperature. Therefore, the increasing temperature makes an indirect positive contribution to the increase in snow cover over the central-eastern Tibetan Plateau in October. The increasing trend of snow cover in November over the central-eastern Tibetan Plateau is attributed to the persistence of abnormal snow cover in the preceding October rather than the snow accumulation change in November. Therefore, it is not appropriate to attribute changes in November snow cover to changes in climatic parameters during the same month.