3.5.1 Weather station data
We obtained air temperature observations from the National Oceanic and Atmospheric Administration (NOAA) Global Historical Climatology Network (Menne et al., 2012). Three stations are located in the study area, all in Kara Ertis basin, namely Altay (737 m a.s.l.), Fuyun (827 m a.s.l.), and Baitag (1186 m a.s.l.). The stations are located south of the Altay Mountains following a northwest-southeast gradient (Fig. 1). Although daily minimum, maximum and average temperatures are available for these stations, we chose to use the latter as the maximum/minimum records are incomplete, often having less than 85% of available data each month. For the same reason, we discarded precipitation and snow depth observations. We chose 2000-2017 as our reference climate period to be consistent with MODIS data; daily mean temperatures were further averaged to obtain monthly, winter (DJF) and spring (MAM) records of mean air temperatures and calculate temperature anomalies relative to the reference period.