ACPD

Atmospheric Chemistry and Physics Discussions

ACPD

1680-7375

Copernicus GmbH

Göttingen, Germany

10.5194/acpd-6-493-2006

NO2 Profile Retrieval using airborne multi axis UV-visible skylight absorption measurements over central Europe

Bruns

¹ Buehler

S. A.

¹ Burrows

J. P.

¹ Richter

¹ Rozanov

¹ Wang

¹ ³ Heue

K.-P.

² Platt

² Pundt

² Wagner

Institute of Environmental Physics, University of Bremen, P.O. Box 33 04 40, 28359 Bremen, Germany

Institute of Environmental Physics, University of Heidelberg, Im Neuenheimer Feld 229, 69120 Heidelberg, Germany

now at: Climate Research and Seismology Department, Royal Netherlands Meteorological Institute (KNMI), P.O. Box 201, 3730 AE De Bilt, The Netherlands

10 01 2006

6 1 493 517

This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

This article is available from http://www.atmos-chem-phys-discuss.net/6/493/2006/acpd-6-493-2006.html

The full text article is available as a PDF file from http://www.atmos-chem-phys-discuss.net/6/493/2006/acpd-6-493-2006.pdf

A recent development in ground-based remote sensing of atmospheric constituents by UV/visible absorption measurements of scattered light is the simultaneous use of several directions with small elevation angles in addition to the traditional zenith-sky pointing. The different light paths through the atmosphere enable the vertical distribution of some atmospheric absorbers such as NO2, BrO or O3 to be retrieved. In this study, the amount of profile information that can be retrieved from such measurements on aircraft is investigated for the trace gas NO2. A Sensitivity study on synthetic data is performed for a combination of four lines of sight (LOS) (0° (nadir), 88°, 92°, and 180° (zenith)) and three wavelength regions [center wavelengths: 362.5 nm, 437.5 nm, and 485.0 nm]. This investigation demonstrates the potential of this LOS/wavelengths setup to retrieve a significant amount of profile information from airborne multiaxis differential optical absorption spectrometer (AMAXDOAS) measurements with a vertical resolution of 3.0 to 4.5 km in the lower troposphere and 2.0 to 3.5 km near flight altitude. Above 13 km the profile information content of AMAXDOAS measurements is sparse. Further, retrieved profiles with a significant amount (up to 3.2 ppbv) of NO2 in the boundary layer over the Po-valley (Italy) are presented. Airborne multiaxis measurements are thus a promising tool for atmospheric studies in the troposphere.