Variations in seasonal snow surface energy exchange during a snowmelt period: an example from the Tianshan Mountains, China

The energy exchange on a snow surface is important for snowmelt and sublimation. Furthermore, a comparison of the snow surface energy exchange between different years at the same location is beneficial for understanding the influence of climate change on snowmelt. In the present study, based in the Tianshan Mountains, China, meteorological factors and the snowmelt rate were measured using an automatic weather station and snow lysimeter during the snowmelt period in a normal snowfall year (2009), an abnormally light snowfall year (2012) and two abnormally heavy snowfall years (2010 and 2013). The energy exchange was calculated according to these meteorological data sets. The climate during the snowmelt periods in 2010 and 2013 was warmer and wetter than that in 2009 and 2012. For all years, net short wave radiation and sensible heat flux were positive, and net long wave radiation and latent heat flux were negative. The maximum difference in the snow surface energy exchange for each of the different years is given as net turbulence. The snowmelt periods in 2010 and 2013 were 15-20days longer than those in 2009 and 2012. The snowmelt rates in 2010 and 2013 were higher than those in 2009 and 2012, especially during the latter days of the snowmelt period. Against the background of a warming and more humid climate in the western Tianshan Mountains, the snowmelt rate will inevitably increase, especially towards the end of the snowmelt period.