Evaluation of modifications to the convective initiation function in the Kain-Fritsch cumulus parameterization

Recent studies in the literature have shown that accounting for the effects of moisture advection in determining the temperature perturbation of the convective parcel can improve the simulation of weak convection. Modifications to the Kain-Fritsch scheme proposed by Ma and Tan (2009) were added to the Coupled Ocean Atmosphere Mesoscale Prediction System (COAMPS®*) and tested over a variety of conditions. Model results were verified against gridded precipitation observations collected over the continental United States. Multiple verification metrics were used, including new neighborhood-based methods that account for near misses by considering model performance at multiple scales.

*COAMPS® is a registered trademark of the Naval Research Laboratory.

Reference: Tan, L-M, and Z. Tan, 2009: Improving the behavior of the cumulus parameterization for tropical cyclone prediction: Convection trigger, Atmos Res