Amplification of the snow melting effect on the heat wave over the Eurasia by absorbing aerosols

Abstract:

<span" roman"="Roman"" new="New">In this study, we present the potential impact of snow darkening effect on the Eurasian heat wave by absorbing aerosols using the NASA GEOS-5 Model experiments with aerosol tracers and a state-of-the-art snow darkening module for the land surface. Results show that snow darkening effect (SDE) can have a significant influence on not only the intensity but also the duration of heatwave during snow melting season, i.e., late spring season over the mid-western Eurasia and early summer season over the central northern Eurasia. During the early snow melting season surface air temperature is significantly increased by 3-6K due to early snow melting and enhanced solar radiation. Moreover enhanced evaporation induced by surface energy surplus during the early melting season leads to the new equilibrium level with lower soil moisture over the Eurasia since snow melting season, and thereby provide favorable condition for severe droughts and heat wave over the large parts of the Eurasia. <span" roman"="Roman"" new="New">This finding suggests that the SDE may play an important role in amplifying <span" roman"="Roman"" new="New">the <span" roman"="Roman"" new="New">snow melting<span" roman"="Roman"" new="New"> effect on large-scale heat wave over the Eurasia.<span" roman"="Roman"" new="New"> Energy and water balance at the surface supporting this findings are also discussed from evaporation-precipitation recycling point of view.