MPAS atmospheric boundary layer simulation under selected stability conditions: Evaluation using the SWIFT dataset

Modeling the transition from mesoscale-to-microscale is necessary for modeling different processes that affect a wind farm and developing forecasting tools that operate at farm scale. The MPAS (Model Prediction Across Scales) is a continuously refinable variable mesh model with dynamic core and physics options adopted from WRF. The model uses the YSU PBL scheme, Kain-Fritsch convection scheme and RRTMg for radiative transfer. The surface layer is parameterized using the Monin-Obhukov parameterizations and the land surface is modeled using the NOAH scheme. The MPAS model is global and has a spatial resolution of 15 km, 41 layers in the vertical and the model top set at 30 km. The model initial conditions are set using NNRP and the surface conditions (including the SST's) are updated every 6 hours. The model was exercised for the entire months of July and August 2012. We compare the model simulations with a limited area simulation performed with WRF for a regional covering the SWIFT (Scaled Wind Farm Technology Facility) facility located at Texas Tech University in northwestern Texas. The WRF model was initialized using data from Texas Mesonet for selected case studies that represent, neutral, stable and convective conditions. The MPAS model produces wind profiles similar to that obtained from the WRF model. However, due to the coarse vertical resolution of the MPAS model the wind profiles were mostly uniform in the lower 200-300 meters of the model under these conditions. We will evaluate the model surface flux calculations of sensible and latent heats between the two models and temperature profiles. Results from an MPAS simulation with a higher vertical resolution will also be presented.