Airborne MAX-DOAS measurements over California: Testing the NASA OMI tropospheric NO sub(2) product

Airborne Multi-AXis Differential Optical Absorption Spectroscopy (AMAX-DOAS) measurements of NO sub(2) tropospheric vertical columns were performed over California for two months in summer 2010. The observations are compared to the NASA Ozone Monitoring Instrument (OMI) tropospheric vertical columns...

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Bibliographic Details
Published in:Journal of geophysical research. Atmospheres 2013-07, Vol.118 (13), p.7400-7413
Main Authors: Oetjen, Hilke, Baidar, Sunil, Krotkov, Nickolay A, Lamsal, Lok N, Lechner, Michael, Volkamer, Rainer
Format: Article
Language:English
Subjects:
Albedo
NASA
Nitrogen dioxide
Pixels
Radiance
Reduction
Satellites
Summer
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Summary:Airborne Multi-AXis Differential Optical Absorption Spectroscopy (AMAX-DOAS) measurements of NO sub(2) tropospheric vertical columns were performed over California for two months in summer 2010. The observations are compared to the NASA Ozone Monitoring Instrument (OMI) tropospheric vertical columns (data product v2.1) in two ways: (1) Median data were compared for the whole time period for selected boxes, and the agreement was found to be fair (R=0.97, slope=1.4 plus or minus 0.1, N=10). (2) A comparison was performed on the mean of coincident AMAX-DOAS measurements within the area of the corresponding OMI pixels with the tropospheric NASA OMI NO sub(2) assigned to that pixel. The effects of different data filters were assessed. Excellent agreement and a strong correlation (R=0.85, slope=1.05 plus or minus 0.09, N=56) was found for (2) when the data were filtered to eliminate large pixels near the edge of the OMI orbit, the cloud radiance fraction was2km, and a representative sample of the footprint was taken by the AMAX-DOAS instrument. The AMAX-DOAS and OMI data sets both show a reduction of NO sub(2) tropospheric columns on weekends by 38 plus or minus 24% and 33 plus or minus 11%, respectively. The assumptions in the tropospheric satellite air mass factor simulations were tested using independent measurements of surface albedo, aerosol extinction, and NO sub(2) profiles for Los Angeles for July 2010 indicating an uncertainty of 12%. Key Points * Airborne and OMI satellite NO2 VCD compare within 12% * Agreement applies over high surface albedo and summer in California * Reduction in NO2 VCD during weekends is highly significant
ISSN:2169-897X
2169-8996
DOI:10.1002/jgrd.50550