Numerical Simulation of Falling‐Snow Deposition Pattern Over 3D‐Hill

Abstract

AbstractSnow distribution over complex terrain is an important input quantity for hydrological modeling. Earlier numerical studies on falling‐snow deposition pattern mostly focused on two‐dimensional (2D) hills. This is simulated over a three‐dimensional (3D) hill using a large‐eddy simulation model. It is shown that for both 2D and 3D cases, the hill blocking effect leads to the formation of a snow accumulation zone on the windward slope. For the 3D case, the maximum snow deposition occurs on the leeward toe, but not for the 2D case under the same background conditions. The main reason for these differences is that the spanwise terrain change in the 3D case weakens this hill blocking effect and concurrently generates terrain‐scale vortices which cause spatially variable snow depositions. It is found that an additional snow accumulation zone forms on the leeward slope of the 3D‐hill due to the presence of a horseshoe vortex there. The low wind velocity regime bracketed by the vorticity streamers forms another large snow accumulation zone on the leeward toe. While the results here are only applicable to small hills in a mountain chain, they provide the necessary information for the parameterization of large‐scale snow patterns for hydrological modeling.