Summary and Directions for Future Research

This publication describes a research project founded upon a combination of state-of-the-art meteorological field and modeling techniques to predict PBL dispersion 

FIGURE 3.20 (See color insert following page 46.) HPAC simulated 24-h surface GB plumes at 1200 UTC 9 May 2005 (a) control run and (b) FDDA run. 

Based on these results, it is reasonable to hypothesize that FDDA with ACARS data could significantly improve the quality of mesoscale NWP and the subsequent dispersion prediction in the atmospheric boundary layer. The hypothesis needs to be systematically tested. 

An advanced mesoscale model may perform well in some cases but not in others, and the model responses to data assimilation are likely to vary with weather scenarios. There would be a potential benefit of using several model winds separately to run HPAC. A composite result of the HPAC runs would give a more complete depiction of the potential surface-based transport of hazardous agents. Also, the latest version of HPAC allows us to display dispersion output within a geographic information system (GIS) environment. We should explore all possible GIS applications in dispersion modeling and damage assessment. 

The MM5 model will eventually need to be replaced by the new-generation Weather Research and Forecasting (WRF) model (e.g., Klemp 2004) to provide meteorological data inputs to HPAC. WRF has many improved features over MM5 and will enhance our ability to generate more timely and accurate near-surface flow for dispersion computation in an urban setting. Also, we would like to evaluate the impact of ACARS data on WRF/HPAC simulations. An interesting experiment would be to assimilate both WTM and ACARS data simultaneously into the WRF model. 

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