Application of Satellite-constrained Chemical Lateral Boundary Conditions to NOAA’s Air Quality Forecast Capability – A Case Study in Support of FIREX-AQ

The on-going Fire Influence on Regional to Global Environments and Air Quality (FIREX-AQ) campaign aims to improve understandings of the impacts of wild and agricultural fires on weather, climate, and air quality, thus to provide better information to public health and land management. A team of experts comprised of forecast and modeling, ground, aircraft, and satellite measurements has been assembled to maximize the gain of this campaign. NOAA’s National Air Quality Forecast Capability (NAQFC) is one of the systems to provide air quality forecast to the campaign. However, the operational NAQFC suffers deficiencies in chemical lateral boundary conditions (CLBCs) by using climatologically averaged conditions, which may limit its forecast accuracy in both ozone and PM_2.5 to capture the influence of long-range transported air pollution. This problem tends to be more prominent in certain chemical weather episodes, such as Canadian wild fire plume transport, as expected in FIREX-AQ. Since use of real-time CLBCs from global chemical transport models is not available in the near future, we developed an alternative solution that utilized more up-to-date climatological CLBCs constrained with the near-real time Aerosol Optical Depth (AOD) measured by the Visible Infrared Imaging Radiometer Suite (VIIRS) onboard Suomi-NPP and JPSS-1 (NOAA-20). In support of FIREX-AQ, we conduct daily air quality forecast using NAQFC with the VIIRS constrained CLBCs, which is the first time for such CLBCs to be used for campaign forecast support. The forecast results will be compared with the ones out of the NAQFC operational simulations that use the default climatological CLBCs, and be evaluated against the available observations from various platforms to check applicability and robustness of VIIRS constrained CLBCs. The preliminary results will be reported in this presentation.