A Conservative Downscaling of Satellite-Detected Chemical Compositions: NO2 Column Densities of OMI, GOME-2, and CMAQ

Details

• Journal Title:
  Remote Sensing
• Personal Author:
  Kim, Hyun ; Lee, Sang-Mi ; Chai, Tianfeng ; Ngan, Fong ; Pan, Li ; Lee, Pius
• NOAA Program & Office:
  OAR (Oceanic and Atmospheric Research) ; CICS (Cooperative Institute for Climate and Satellites) ; ARL (Air Resources Laboratory)
• Description:
  A conservative downscaling technique was applied when comparing nitrogen dioxide (NO2) column densities from space-borne observations and a fine-scale regional model. The conservative downscaling was designed to enhance the spatial resolution of satellite measurements by applying the fine-scale spatial structure from the model, with strict mass conservation at each satellite footprint pixel level. With the downscaling approach, NO2 column densities from the Ozone Monitoring Instrument (OMI; 13 x 24 km nadir footprint resolution) and the Global Ozone Monitoring Experiment-2 (GOME-2; 40 x 80 km) show excellent agreement with the Community Multiscale Air Quality (CMAQ; 4 x 4 km) NO2 column densities, with R = 0.96 for OMI and R = 0.97 for GOME-2. We further introduce an approach to reconstruct surface NO2 concentrations by combining satellite column densities and simulated surface-to-column ratios from the model. Compared with the Environmental Protection Agency's (EPA) Air Quality System (AQS) surface observations, the reconstructed surface concentrations show a good agreement; R = 0.86 for both OMI and GOME-2. This study demonstrates that the conservative downscaling approach is a useful tool to compare coarse-scale satellites with fine-scale models or observations in urban areas for air quality and emissions studies. The reconstructed fine-scale surface concentration field could be used for future epidemiology and urbanization studies.
• Source:
  Remote Sensing, 10(7), 17.
• DOI:
  https://doi.org/10.3390/rs10071001
• Document Type:
  Journal Article
• Rights Information:
  CC BY
• Compliance:
  Submitted
• Main Document Checksum:
  urn:sha256:70a715a0ff6013a5b26e14c6b8ded3f2a6ccfaf6fe12ead6755aff402f53b5a5
• Download URL:
  https://repository.library.noaa.gov/view/noaa/20330/noaa_20330_DS1.pdf
• File Type:
  [PDF - 5.20 MB ]