Ammonia (NH3) is the major base in the atmosphere and comprises a large fraction of atmospheric reactive nitrogen. NH3 contributes significantly to particulate matter (PM) through the formation of…

This is a $161,735 grant award from the National Aeronautics and Space Administration (NASA) to Atmospheric & Environmental Research Inc., a subsidiary of Verisk Analytics, Inc. The grant is for research to refine and validate an algorithm that uses data from the Cross-track Infrared Sounder (CrIS) instrument aboard the Suomi National Polar-orbiting Partnership (SNPP) satellite to measure atmospheric ammonia (NH3) levels. The research aims to use the CrIS NH3 data to improve understanding of NH3 distributions and emissions from sources like agriculture, biomass burning, and urban areas. The work involves using spatial and temporal analysis techniques to extract sub-pixel source information and estimate NH3 fluxes, as well as validating the CrIS NH3 data against in situ aircraft measurements. The results will be used to enhance the operational CrIS NH3 data product and support air quality modeling and monitoring efforts. No set-aside designation was applied to this award.

Ammonia (NH3) is the major base in the atmosphere and comprises a large fraction of atmospheric reactive nitrogen. NH3 contributes significantly to particulate matter (PM) through the formation of ammonium salts, contributing to cardiovascular and respiratory illnesses worldwide. NH3 also contributes to nitrogen deposition flow of excess nitrogen is one of the largest threats to biosphere integrity. Agriculture is the largest global source of NH3, and but there are also appreciable emissions of NH3 from biomass burning. However, major uncertainties exist in NH3 emission rates from all sources, and on all scales. This is due to sparse quality in situ measurements. Measurements from satellite instruments provide an alternative method for capturing the spatial and temporal variability of NH3, especially outside europe and north america, where monitoring networks range from limited to non-existent. The NASA tropospheric emission spectrometer (TES) was the first satellite instrument to measure NH3 from space TES captured seasonal variability over large regions, and detected hot spots over india and china. TES also revealed NH3 emissions from biomass burning in south america and africa, which were also observed by the metop infrared atmospheric sounder instrument (IASI) instrument. New NH3 observations from the snpp cross-track infrared sounder (CRIS) have great potential to improve our understanding of NH3 distributions and emissions because CRIS has lower noise than IASI (0.04 K) and significantly greater spatial coverage than TES. While CRIS NH3 is not yet an official NASA product, the algorithm will become an operational product in 2018. IT has already been used to obtain NH3 over canada, california and the southeastern US, as well as over a number of aeronet sites. These data are currently being validated against ground based ftir and aircraft NH3 measurements, and have provided information on the spatial and temporal variability of NH3 over these regions. We propose to refine the algorithm with some continued validation and to demonstrate the utility of the CRIS NH3 data by applying some novel approaches to obtain emission estimates and source locations. We will: a) use a tessellation technique to extract sub-pixel information from repeated CRIS overpasses. This will provide more precise locations of sources of high NH3 emissions. B) use an image rotation approach based on prevailing wind direction to create composite images of regions with fires, confined animal feedlot operations (CAFOS), or other intensive agriculture, as well over selected large urban areas (LOS angeles). These images can be used to compute NH3 flux density from the areas of interest, which can then be used to estimate emissions. C) carry out a validation exercise using in situ measurements of NH3 made with an aerodyne model tildas C laser system onboard the NSF/ncar C-130 during the summer 2018 we-can (western wildfire experiment for cloud chemistry, aerosol absorption and nitrogen) campaign, which will complement ongoing efforts under existing NASA contracts the results will be used to make improvements to the CRIS NH3 algorithm over smoke scenes. D) update emission inventories with the information obtained from CRIS, then compare geos-chem model output with data obtained from aircraft campaigns (discover-AQ, frappe, we-can) and surface measurememts (AMON). This work will lead to an improved CRIS NH3 product and will test some novel yet computationally inexpensive techniques to provide source location and emission estimates to end-users in the air quality community.