SLM_Polar

Modified simplifid versions, recoded in Python, of the Noah Land Surface Model used in conjunction with the Mellor-Janjic-Yamada surface layer scheme (Noah MYJ) and the Noah MultiPhysics scheme (Noah-MP) from the WRF 4.5.1 meso-scale model.

Modifications are used to correct the fact that original WRF schemes place strong limits on the turbulent collapse, leading to lower surface temperature gradient at low wind speeds. Modified versions show a better performance in reproducing positive temperature gradients over forested areas in the Arctic winter.

Noah-MP is found to perform better than Noah-LSM–MYJ because the former is a 2-layer model which explicitly takes into account the effect of the forest canopy. Indeed a non-negligible temperature gradient is maintained below the canopy at high wind speeds, leading to overall larger gradients than in the absence of vegetation.