GC43A-0683:
Improved solar irradiance forecast with Weather Research and Forecasting model: A Sensitivity test of shallow cumulus clouds to the turbulence process

Thursday, 18 December 2014
Chang Ki Kim1, Eric A Betterton1, Michael Leuthold1, William Holmgren2 and Alex Cronin2, (1)University of Arizona, Department of Atmospheric Sciences, Tucson, AZ, United States, (2)University of Arizona, Department of Physics, Tucson, AZ, United States
Abstract:
Accurate forecasts of solar irradiance are required for electric utilities to economically integrate substantial amounts of solar power into their power generation portfolios. A common failing of numerical weather models is the prediction of shallow cumulus clouds which are generally difficult to be resolved due to complicated processes in the planetary boundary layer. The present study carried out the sensitivity test of turbulence parameterization for better predicting solar irradiance during the shallow cumulus events near the state of Arizona by using the Weather Research and Forecasting model. The results from the simulations show that increasing the exchange coefficient leads to enhanced vertical mixing and a deeper mixed layer. At the top of mixed layer, an adiabatically ascending air parcel achieved the water vapour saturation and finally shallow cumulus is generated. A detailed analysis will be discussed in the upcoming conference.