An overview of the NOAA/NWS/NCEP Real-Time Mesoscale Analysis (RTMA) system with extensions for the atmospheric boundary layer

NOAA develops decision support systems to aid homeland security decision makers in the event that harmful toxic materials are released to the atmosphere. Specifically, NWS Forecast Offices and the NWS-NCEP Hydro-meteorological Prediction Center provide dispersion model forecasts driven by NCEP Numerical Weather Prediction (NWP) models to emergency response managers. In addition, NCEP NWP predictions are made available to the Department of Homeland Security Inter-Agency Modeling and Atmospheric Assessment Center and the DOD Defense Threats Reduction Agency to drive their dispersion models. The atmospheric planetary boundary layer (PBL) height is a critical parameter for dispersion decision support tools. Accurate assessment of boundary layer information at finer scales should improve the Nation's ability to assess the effects of a toxic release.

This project seeks to use recent satellite technologies and in-situ measurements to demonstrate a Real-Time Mesoscale Analysis (RTMA) of PBL information for use by plume dispersion modelers. Specifically, PBL height products derived from real-time radiosondes and Meteorological Data Collection and Reporting System (MDCRS/ACARS) aircraft meteorological profiles are now available for model evaluation and assimilation. . Boundary layer depths derived vertical reflectivities from NOAA WSR-88D) Doppler radars will also be tested. NASA global positioning system (GPS) instruments aboard satellites (COSMIC) will be assimilated along in the NCEP 5 km RTMA. Ground based lidar measurements from NASA MPLNET as well as CALIPSO satellite profiles will be used to evaluate the analyses. NOAA funded Center for Atmospheric Science (NCAS) and other ground lidars are leveraged for evaluation.

Additional dispersion related products such as atmospheric stability, will be computed using the existing RTMA analyses of winds, temperature and moisture along with the PBL products. The stability analysis can help emergency managers identify areas conducive for weak dispersion which would be vulnerable to high toxic pollutant concentrations if a release did occur.