P66 Evaluation of WRF for fine scale surface energy balance modeling in Phoenix

Shaffer, S. R., Arizona State University

An evaluation of urbanized WRF v3.2 with flux-tower observations in Phoenix, Arizona, was performed during synoptically-quiescent high-pressure periods in winter 2011 and pre-monsoon 2012. Examination of diurnal variation in surface energy balance (SEB) constituent fluxes, in conjunction with the diagnostic 2-meter temperature (T2), indicate that model performance cannot be assessed based solely on T2, an observed variable provided by many sensor networks, and as such, often employed within metrics of model performance. Land use and land covers were derived from combining NLCD 2006 urban classes with MODIS. The simulation employed five domains to 333 meter horizontal resolution, with 40 vertical levels, testing the default and two previously published parameterizations of Phoenix in the urban canopy model (UCM), versus bulk, for a local (MYJ) and non-local (YSU) PBL schemes. We show that there are cases when, although the simulated temperature has good agreement with observations, the individual SEB terms can have considerable error, and employing UCM adapted for Phoenix can reduce errors in the SEB components. Regarding T2, all cases tested perform well during mid-day unstable convective periods. Whereas, both UCM and PBL give rise to mixed benefit during other stability regimes, with YSU consistently closer to observations than MYJ except for when UCM was not used with MYJ. Other results will also be presented.