Temporal and Spatial Variation of Lake Ice Phenology and Its Influencing Factors in the Tibetan Plateau

To clarify the lake ice phenology of the Tibetan Plateau and its response to dimate change, taking 40 lakes with larger area (>100km ²) in the Tibetan Plateau as the research subject, using threshold method with MODIS10 data, the phenology of lake ice in the Tibetan Plateau was obtained from 2000 to 2015, and the spatial-temporal variations of lake ice and its relationship were analyzed with climate change. Results show that the freeze onset (FO) of lakes ice generally appears in early November to mid December, the freeze up (FU) of lakes ice appears in the middle of November to the early January of next year, the break onset (BO) of lakes ice appears in the middle of march to early may, and the break up (BU) of lakes ice appears in the middle of April to early June. The mean ice duration (ID) are 176 days, the mean completely ice duration (CID) are around 130 days. There are obvious regional differences in the lake ice phenology of the Tibetan Plateau, the FO of the north lakes is the earliest, the BU of the north lakes is the latest, and the ID of the north lakes is the longest; the FO of the south lakes is the latest, the BU of the south lakes is the earliest, and the ID of the south lakes is the shortest. The trend of lake ice phenology change of most lakes is not significant. CID and ID change is large in northern lakes, CID and ID change is small in the southern and eastern lakes during 2000—2015. The temporal and spatial changes of lake ice phenology are mainly affected by temperature, precipitation and wind speed. The temperature is the main influence factor, the increase of the temperature and rainfall will cause the freezing period to be shortened, and the wind speed has a certain impact on the lake ice phenology.