Parameterized convective momentum adjustment

What is the net influence of organized convection on the environmental momentum field? The interaction between organized convection and the environmental wind field is complex, but its representation is critical to accurate weather and climate prediction. Some model convective parameterization (CP) schemes neglect momentum adjustment, owing more to difficulties in its accurate parameterization than to unimportance.

Here, we utilize a modified version of the Weather Research and Forecasting (WRF) model in which momentum tendencies are passed to the solver from the Kain-Fritsch CP scheme. Comparisons are made, using simulations of an idealized MCS, between high-resolution explicit convection runs, and lower resolution runs with and without the parameterized momentum adjustment. Two different formulations of the adjustment are investigated and evaluated.

Results demonstrate the importance of this process, even for shorter-term simulations. The relevance of the formulations tested here is discussed, with implications for broader applicability to NWP and climate models.