4.4    A Weather Forecasting System for Complex Urban Environments (uWRF)

Gonzalez, Jorge E., The City College of New York, Bob Bornstein, San Jose State University, and Estatio Gutierrez, San Jose State University

WRF mesoscale model is coupled to a multi-layer urban canopy model that permits a direct interaction of urban canyons with the PBL.  This parameterization recognizes three different urban surfaces to account for thermal and mechanical effects of the urban environment including a building scale energy model to account for anthropogenic heat contributions due to indoor-outdoor temperature differences.  High resolution (250m.) urban canopy parameters from the US National Urban Database are employed to initialize the multi-layer urban parameterization.  This new urban parameterization, referred is assessed for several case studies, in anticipation of next generational weather forecasting systems for complex urban environments.  The first case is the evaluation of the evolution and the resulting urban heat island formation associated to a 3-day heat wave in New York City (NYC) during the summer of 2010.  Data from a dense network of surface weather stations, wind profilers and Lidar measurements are compared to model outputs over Manhattan during the 3-days event. The thermal and drag effects of buildings represented in the multilayer urban canopy model improves simulations over urban regions.  The accuracy of the energy simulation is further assessed against single unit building energy models with positive results with new approach.  Results are further used to quantify the energy consumption of the buildings during the heat wave due to air conditioning.