What caused the spatial heterogeneity of lake ice phenology changes on the Tibetan Plateau?

As the Third Pole of the Earth, the Tibetan Plateau has numerous lakes with seasonal ice cover. The ice phenology of these lakes has undergone remarkable changes in recent years. We obtained the ice phenology records for 71 lakes for the period of 2001 to 2020 and found overall later trends for both freeze-up and break-up dates. As a result, the changes in ice cover duration showed great spatial heterogeneity. Therefore, we analyzed the causes of lake ice phenology changes from two aspects: climate change and lake properties. The results showed that the changes in air temperature dominated the variations in ice phenology, followed by solar radiation. The weakened wind power in the northeastern part of the plateau was favorable for the delay of break-up end dates and the extension of ice cover durations. Furthermore, by changing the lake size and salinity, water balance changes led to aggravated ice phenology changes for some lakes, while for some other lakes, they moderated or even reversed the changes caused by other climatic factors. In general, the spatial inconsistency of changes in multiple climatic factors (especially differences between the northeastern and southwestern parts) during the 20 years was the main reason for the heterogeneity of lake ice phenology changes on the Tibetan Plateau. This study preliminarily summarized some of the effects of climate change and lake properties on lake ice phenology, and the results are important for understanding the physical mechanism of lake ice phenology changes under climate change.