10.7 Sensitivity of HWRF Forecasts to Cumulus Parameterizations

Biswas, Mrinal K., National Center for Atmospheric Research, Ligia R Bernardet, CIRES,NOAA/ESRL/GSD, Shaowu Bao, CIRES,NOAA/ESRL/GSD

Previous research has documented that tropical cyclone forecasts generated with both global and regional models are highly sensitivity to the choice of cumulus parameterizations. They have shown significant impact on the hurricane track, intensity and wind structure. In this study, the Hurricane WRF (HWRF) model with 27/9/3 km resolution is used to assess the impact of different cumulus parameterization schemes for Atlantic and Eastern Pacific storms. Our study shows cumulus parameterizations affect both the large- and storm-scale fields, impacting track and intensity forecasts. Additionally, the storm structures are significantly different when different schemes are used. 

To accomplish this work, the Developmental Testbed Center (DTC) and the NCAR Mesoscale and Microscale division have collaborated to make more  cumulus schemes available to run with the HWRF model. A greater availability of schemes offers the possibility of more extensive research by the community and the HWRF developers to evaluate the impact of the convective parameterizations. These additional physics schemes can be used for physics-diversity ensemble forecasting as well as for exploring alternative physics for the operational model.