HPAC Data Assimilation Study Utilizing New York State Mesonet Data

The Hazard Prediction and Assessment Capability (HPAC) software is the main atmospheric transport and dispersion (AT&D) tool utilized at the Defense Threat Reduction Agency (DTRA) Technical Reachback: the Interagency Modeling and Atmospheric Assessment Center (IMAAC) technical hub for chemical, biological, radiological, nuclear and explosive national events. An accurate characterization of the 2D and 3D weather variables—most importantly, the temporal evolution of the lower level winds, boundary layer height, and surface heat flux—are necessary in order produce reliable areas of potential hazards that are used to inform emergency response personnel. The data assimilation tool within HPAC is tested to evaluate how AT&D results vary as additional observational data is integrated with NWP. The New York State Mesonet standard stations within the New York City region provide horizontal and vertical observations that are utilized for daytime and night time release simulations.