Development of a linked operational mesoscale model and an urban emergency assessment system

In this study, we seek to provide guidance to emergency responders in the case of the accidental or intentional release of hazardous chemical, biological, or radiological materials into the atmosphere. To this end, we will link the Naval Research Laboratory (NRL) coupled ocean-atmosphere mesoscale prediction system-on scene (COAMPS-OS® ) to an urban-oriented emergency assessment system (CT-Analyst®1). COAMPS-OS is a state-of-the-art, nonhydrostatic numerical weather prediction model coupled with an ocean model and utilizing sophisticated physical parameterization schemes, including the WRF urban canopy parameterization (UCP), to make mesoscale and tactical scale forecasts in support of DOD operations world wide. CT-Analyst is used to evaluate airborne contaminant transport threats and to aid in making rapid decisions for complex geometry environments such as coastal urban areas. As a necessary first step in creation of the linked system, the COAMPS-OS UCP must be carefully examined and improved in order to provide the optimum meteorological input to CT-Analyst. We will utilize both three-dimensional, multiple nest and single column model implementations of COAMPS. We seek to understand the impact of urban structure parameters, including grid volume mean building height, building fraction, roof top fraction, anthropogenic heating, urban drag, and building morphology on the behavior of the coastal urban boundary layer. We will perform detailed comparisons with LES models in order to identify deficiencies.