Validation of Global Weather Forecast and Climate Models Over the North Slope of Alaska
| Xie, Shaocheng | Lawrence Livermore National Laboratory |
| Klein, Stephen | Lawrence Livermore National Laboratory |
| Boyle, Jim | Lawrence Livermore National Laboratory |
| Fiorino, Michael | DOE/Lawrence Livermore National Laboratory |
| Hnilo, Justin | DOE/Lawrence Livermore National Laboratory |
| Phillips, Thomas | PCMDI/LLNL |
| Potter, Gerald | Lawrence Livermore National Laboratory |
| Beljaars, Anton | ECMWF |
Category: Field Campaigns
Data collected from the ARM Mixed-Phase Arctic Cloud Experiment (M-PACE) field campaign over the North Slope of Alaska (NSA) in October have been used to validate Arctic clouds and radiation simulated by the global weather-forecasting and climate models of several major modeling centers. This study evaluated predictions of these M-PACE phenomena by the European Center for Medium-Range Weather Forecasts (ECMWF) model and by two U. S. climate models, the Community Atmosphere Model (CAM3) of the National Center for Atmospheric Research and the Atmosphere Model (AM2) of the NOAA Geophysical Fluid Dynamics Laboratory (GFDL). Arctic weather forecasts of the ECMWF model during the M-PACE period were evaluated, while the climate models were diagnosed in a comparable weather-forecasting framework developed for the CCPP-ARM Parameterization Testbed (CAPT), a joint effort of ARM and DOE’s Climate Change Prediction Program (CCPP). All the models show skill in predicting various cloud types observed during M-PACE; however they underpredict cloud amount in the early period of the experiment when both multilayered and boundary-layer mixed-phase clouds are present. During this period, the simulated cloud bases by the two climate models (CAM3 and AM2) are too low compared to the observations. Moreover, the microphysical properties of the boundary-layer mixed-phase clouds are in substantial error. The ARM M-PACE data also reveal deficiencies in the model simulations of radiative fluxes at the surface and the top of the atmosphere that are associated with the errors in their predicted cloud fields. All the models overestimate the outgoing longwave radiation at the top of the atmosphere and the ECMWF and CAM3 models substantially underestimate the downwelling longwave radiation at the surface at the times of the boundary layer clouds. Errors in the model cloud and radiation fields also can have a large impact on the simulated surface energy budget. For example, the ECMWF model exhibits a much larger energy loss than the observations at the surface during the M-PACE period. More in-depth analysis is being conducted in order to fully interpret the model results and understand the causes of these errors.
This poster will be displayed at the ARM Science Team Meeting.
