A Conservative Downscaling of Satellite-Detected Chemical Compositions: NO2 Column Densities of OMI, GOME-2, and CMAQ
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 spat...
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doaj-ba4321b6ad8942d1af8c1a3cdd6f91212020-11-25T00:38:50ZengMDPI AGRemote Sensing2072-42922018-06-01107100110.3390/rs10071001rs10071001A Conservative Downscaling of Satellite-Detected Chemical Compositions: NO2 Column Densities of OMI, GOME-2, and CMAQHyun Cheol Kim0Sang-Mi Lee1Tianfeng Chai2Fong Ngan3Li Pan4Pius Lee5Air Resources Laboratory, National Oceanic and Atmospheric Administration, College Park, MD 20740, USASouth Coast Air Quality Management District, Diamond Bar, CA 91765, USAAir Resources Laboratory, National Oceanic and Atmospheric Administration, College Park, MD 20740, USAAir Resources Laboratory, National Oceanic and Atmospheric Administration, College Park, MD 20740, USAAir Resources Laboratory, National Oceanic and Atmospheric Administration, College Park, MD 20740, USAAir Resources Laboratory, National Oceanic and Atmospheric Administration, College Park, MD 20740, USAA 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 × 24 km nadir footprint resolution) and the Global Ozone Monitoring Experiment-2 (GOME-2; 40 × 80 km) show excellent agreement with the Community Multiscale Air Quality (CMAQ; 4 × 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.http://www.mdpi.com/2072-4292/10/7/1001downscalingNO2 column densityOMIGOME-2CMAQ |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Hyun Cheol Kim Sang-Mi Lee Tianfeng Chai Fong Ngan Li Pan Pius Lee |
spellingShingle |
Hyun Cheol Kim Sang-Mi Lee Tianfeng Chai Fong Ngan Li Pan Pius Lee A Conservative Downscaling of Satellite-Detected Chemical Compositions: NO2 Column Densities of OMI, GOME-2, and CMAQ Remote Sensing downscaling NO2 column density OMI GOME-2 CMAQ |
author_facet |
Hyun Cheol Kim Sang-Mi Lee Tianfeng Chai Fong Ngan Li Pan Pius Lee |
author_sort |
Hyun Cheol Kim |
title |
A Conservative Downscaling of Satellite-Detected Chemical Compositions: NO2 Column Densities of OMI, GOME-2, and CMAQ |
title_short |
A Conservative Downscaling of Satellite-Detected Chemical Compositions: NO2 Column Densities of OMI, GOME-2, and CMAQ |
title_full |
A Conservative Downscaling of Satellite-Detected Chemical Compositions: NO2 Column Densities of OMI, GOME-2, and CMAQ |
title_fullStr |
A Conservative Downscaling of Satellite-Detected Chemical Compositions: NO2 Column Densities of OMI, GOME-2, and CMAQ |
title_full_unstemmed |
A Conservative Downscaling of Satellite-Detected Chemical Compositions: NO2 Column Densities of OMI, GOME-2, and CMAQ |
title_sort |
conservative downscaling of satellite-detected chemical compositions: no2 column densities of omi, gome-2, and cmaq |
publisher |
MDPI AG |
series |
Remote Sensing |
issn |
2072-4292 |
publishDate |
2018-06-01 |
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 × 24 km nadir footprint resolution) and the Global Ozone Monitoring Experiment-2 (GOME-2; 40 × 80 km) show excellent agreement with the Community Multiscale Air Quality (CMAQ; 4 × 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. |
topic |
downscaling NO2 column density OMI GOME-2 CMAQ |
url |
http://www.mdpi.com/2072-4292/10/7/1001 |
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