Using NASA Earth Observations to Improve Air Quality Decision-Making Activity in Indian Subcontinent

The National Center for Atmospheric Research (NCAR) in collaboration with the Indian Institute of Tropical Meteorology (IITM) and the Indian Meteorological Department (IMD) of the Ministry of Earth Sciences have developed an air quality early warning systems (AQEWS) for entire South Asia to timely alert the public of forthcoming air pollution episodes and implement temporary emission control measures to reduce the predicted air pollution events. The system currently assimilates the Moderate Resolution Imaging Spectroradiometer (MODIS) aerosol optical depth (AOD) retrievals to improve initialization of aerosol chemical composition but we are in the process of transitioning to the assimilation of Visible Infrared Imaging Spectroradiometer (VIIRS) AOD retrievals to ensure AQEWS continues to benefit from space-borne observations of AOD. We also use the active fire location information from MODIS and VIIRS to refine daily fire emissions in our forecasting system. The assimilation of MODIS AOD retrievals improved the accuracy of fine particulate matter forecasts in Delhi by 70-86% during the crop-residue burning season. Large improvement in particulate matter forecasts due to MODIS AOD assimilation are also seen during a dust event that affected western India. We have also developed a decision support system to help policy makers make informed decisions about temporary emission controls to reduce the amount of predicted pollution in New Delhi. Decision-makers regularly use these air quality forecasts to impose and/or lift-off temporary restrictions on targeted emission sources to improve air quality particularly in Delhi. Specifically, the Commission for Air Quality Management (CAQM) uses these forecasts to activate the Graded Response Action Plan 72 hours in advance in Delhi. Different capabilities of the AQEWS will be discussed in detail during the presentation.