Satellite nadir NO2 validation based on zenith-sky, direct-sun and MAXDOAS network observations
Gaia Pinardi
(1)
,
Michel van Roozendael
(1)
,
Jean-Christopher Lambert
(1)
,
José Granville
(1)
,
François Hendrick
(1)
,
Clio Gielen
(1)
,
Alexander Cede
(2)
,
Ygo Kanaya
(3)
,
Hitoshi Irie
(4)
,
Folkard Wittrock
(5)
,
Andreas Richter
(5)
,
Enno Peters
(5)
,
Thomas Wagner
(6)
,
Myojeong Gu
(6)
,
Julia Remmers
(6)
,
Johannes Lampel
(7, 6)
,
Udo Friess
(7)
,
Tim Vlemmix
(8)
,
Ankie Piters
(9)
,
Nan Hao
(10)
,
Martin Tiefengraber
(11)
,
Jay Herman
(12, 2)
,
Nader Abuhassan
(2, 12)
,
Robert Holla
(13)
,
Alkis Bais
(14)
,
Dimitris Balis
(14)
,
Theano Drosoglou
(14)
,
Natalia Kouremeti
(15, 14)
,
Jari Hovila
(16)
,
J. Chong
(17)
,
Oleg Postylyakov
(18)
,
Jianzhong Ma
(19)
,
Florence Goutail
(20)
,
Jean-Pierre Pommereau
(20)
,
Andrea Pazmino
(20)
,
Monica Navarro
(21)
,
Olga Puentedura
(21)
,
Huan Yu
(1)
1
BIRA-IASB -
Belgian Institute for Space Aeronomy / Institut d'Aéronomie Spatiale de Belgique
2 GSFC - NASA Goddard Space Flight Center
3 RIGC - Research Institute for Global Change
4 CEReS - Center for Environmental Remote Sensing [Chiba]
5 IUP - Institute of Environmental Physics [Bremen]
6 MPIC - Max Planck Institute for Chemistry
7 Institut für Umweltphysik [Heidelberg]
8 Department of Geoscience and Remote Sensing [Delft]
9 KNMI - Royal Netherlands Meteorological Institute
10 IMF - DLR Institut für Methodik der Fernerkundung / DLR Remote Sensing Technology Institute
11 Institute of Meteorology and Geophysics [Innsbruck]
12 JCET - Joint Center for Earth Systems Technology [Baltimore]
13 MOHp - Meteorologisches Observatorium Hohenpeißenberg
14 Laboratory of Atmospheric Physics [Thessaloniki]
15 PMOD/WRC - Physikalisch-Meteorologisches Observatorium Davos/World Radiation Center
16 FMI - Finnish Meteorological Institute
17 GIST - Gwangju Institute of Science and Technology
18 IAP - A.M.Obukhov Institute of Atmospheric Physics
19 CAMS - Chinese Academy of Meteorological Sciences
20 STRATO - LATMOS
21 INTA - Instituto Nacional de Técnica Aeroespacial
2 GSFC - NASA Goddard Space Flight Center
3 RIGC - Research Institute for Global Change
4 CEReS - Center for Environmental Remote Sensing [Chiba]
5 IUP - Institute of Environmental Physics [Bremen]
6 MPIC - Max Planck Institute for Chemistry
7 Institut für Umweltphysik [Heidelberg]
8 Department of Geoscience and Remote Sensing [Delft]
9 KNMI - Royal Netherlands Meteorological Institute
10 IMF - DLR Institut für Methodik der Fernerkundung / DLR Remote Sensing Technology Institute
11 Institute of Meteorology and Geophysics [Innsbruck]
12 JCET - Joint Center for Earth Systems Technology [Baltimore]
13 MOHp - Meteorologisches Observatorium Hohenpeißenberg
14 Laboratory of Atmospheric Physics [Thessaloniki]
15 PMOD/WRC - Physikalisch-Meteorologisches Observatorium Davos/World Radiation Center
16 FMI - Finnish Meteorological Institute
17 GIST - Gwangju Institute of Science and Technology
18 IAP - A.M.Obukhov Institute of Atmospheric Physics
19 CAMS - Chinese Academy of Meteorological Sciences
20 STRATO - LATMOS
21 INTA - Instituto Nacional de Técnica Aeroespacial
Résumé
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.