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.