Satellite nadir NO<sub>2</sub> validation based on zenith-sky, direct-sun and MAXDOAS network observations - INSU - Institut national des sciences de l'Univers Access content directly
Conference Papers Year : 2016

Satellite nadir NO2 validation based on zenith-sky, direct-sun and MAXDOAS network observations

Florence Goutail
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  • PersonId : 968972
Jean-Pierre Pommereau
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  • PersonId : 930119
Andrea Pazmino
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  • PersonId : 968970


Since more than fifteen years, total and tropospheric NO2 columns have been retrieved from nadir space-borne sensors such as SCIAMACHY on ENVISAT, OMI on AURA and GOME-2 on MetOp platforms. The NO2 data products are generally retrieved in three main steps: (1) a DOAS spectral analysis yielding the total column amount of NO2 along the slant optical path, (2) an estimation of the stratospheric NO2 column, to be subtracted from the total column to derive the tropospheric contribution, and (3) a conversion of the total and tropospheric slant columns into vertical columns based on airmass factor calculations which require a-priori knowledge of the NO2 vertical distribution and surface albedo, as well as information on cloud cover and height. In this study we combine correlative measurements available from several ground-based remote sensing networks to address the validation of (1) the GOME-2 GDP 4.8 NO2 products generated within the EUMETSAT O3M-SAF project, and (2) the SCIAMACHY, OMI and GOME-2 TEMIS product. Zenith-sky DOAS/SAOZ measurements from the NDACC network are used to assess the stratospheric NO2 columns retrieved from the satellite, while the consistency of the total and tropospheric NO2 columns in urban, sub-urban and back-ground conditions is investigated using direct-sun Pandora and multi-axis MAXDOAS data sets from about 40 stations. Where available, vertical profile information from MAXDOAS measurements is used to assess the reliability of the different satellite a-priori profile shapes. Results are discussed in terms of observed biases between satellite and ground-based data sets, their dependence on location, season and cloud conditions. For stratospheric columns, the uncertainty related to the correction applied for ensuring the photochemical matching between satellite and ground-based observations is also evaluated. The satellite pixels resolution effect is statistically explored in relation to the typical extent of the emission sources at urban site locations, using data from SCIAMACHY 60x30 km², GOME-2 40x80 km² and OMI 13x24 km².
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insu-01313259 , version 1 (09-05-2016)


  • HAL Id : insu-01313259 , version 1


Gaia Pinardi, Michel van Roozendael, Jean-Christopher Lambert, José Granville, François Hendrick, et al.. Satellite nadir NO2 validation based on zenith-sky, direct-sun and MAXDOAS network observations. Living Planet Symposium 2016, May 2016, Prague, Czech Republic. ⟨insu-01313259⟩
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