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Infrared spectroscopy of ozone and related atmospheric constituents

Objective

The objective of the project is to provide spectroscopic data for the following 6 important atmospheric molecules to improve the quality of atmospheric data bases: nitrous oxide(N2O5), hydrogen nitrate, chlorine oxide nitrite(ClONO2), hydrous oxide(HO2), ozone,and hydrogen nitrite.
The experimental and theoretical investigations in the frame of ISORAC have improved the spectroscopic database for the seven molecules

N2O5 dinitrogen pentoxide
HNO3 nitric acid
ClONO2 chlorine nitrate
HO2 hydroperoxyl radical
O3 ozone
HONO nitrous acid
N2O4 dinitrogen tetroxide

This data will help to improve the analysis and understanding of the stratospheric chemistry in two respects:

SHORT TERM ASPECT

The ISORAC data will help to better evaluate and analyse the remote sensing data of EASOE sensors (e.g. MIPAS and LPMA balloon measurements). It will also be used to improve the analysis of other balloon data (e.g. IBEX far-infrared measurements) and some of the UARS retrievals.

LONG TERM ASPECT

The results will help to prepare a database as accurate as possible for remote sensors which will come to operation within the next years. An example is the MIPAS Fourier transform spectrometer, a core instrument on the ENVISAT-1 mission of the European Polar Platform POEM-1 to be launched in 1998. Furthermore, ISORAC will provide spectroscopic inputs for the definition of future sensor systems.
It is planned to improve the accuracy of existing data by at least a factor of 2. The spectroscopic data bases will be updated with this data and will be made available for the analysis of atmospheric measurements, especially the results of the Arctic Ozone Campaign 1991 and 1992.

Different experimental techniques (especially concerning spectral regions and spectral bandwiths) will be applied which guarantee an appropriate validation of the results (eg Fourier transform spectroscopy (in all regions), diode laser spectroscopy (in the infrared), tunable far infrared spectroscopy (in the far infrared).

The theoretical methods used to analyze the experimental results will be based on the highest level quantum molecular theory and will make use of perturbational treatments and direct numerical diagonalization (including resonance effects).

The experimental work will be done in the infrared spectral region (5 to 1000 um), especially in the 10 um region (800 to 1200 cm{-1}), transition region (300 to 500 cm{-1})and the far infrared (below 200 cm{-1}).

The data achieved by theoretical analysis of the experimental results will consist of line positions, line intensities, and pressure broadening coefficients for each molecule being investigated.

The goal of this project is to obtain data with an accuracy better than 3E-4 cm{-1} for line positions, better than 5% for line intensities, and better than 5% for pressure broadening parameters. The minimum accuracy obtained will be at least a factor of two better than the accuracy of data presently available from the atmospheric data bases.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

Deutsches Zentrum für Luft- und Raumfahrt e.V.
Address

82234 Weßling
Germany

Participants (10)

CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE
France
Address
Université De Paris-sud 11 350 Tour 13 Case 76
75252 Paris
Centre National de la Recherche Scientifique (CNRS)
France
Address
Université De Paris Xi (Université Paris-sud)
91405 Orsay
Engineering and Physical Sciences Research Council (EPSRC)
United Kingdom
Address
Polaris House North Star Avenue
SN2 1ET Swindon
Justus-Liebig-Universität Giessen
Germany
Address
Heinrich-buff-ring 58
35392 Giessen
NATIONAL RESEARCH COUNCIL OF ITALY
Italy
Address
Via Panciatichi 64
50127 Firenze
UNIVERSITY OF BOLOGNA
Italy
Address
Viale Risorgimento 4
40136 Bologna
University of Strathclyde
United Kingdom
Address
John Anderson Building 107 Rottenrow
G4 0NG Glasgow
Università degli Studi di Firenze
Italy
Address
Largo Enrico Fermi 2
50125 Firenze
Università degli Studi di Pisa
Italy
Address
Piazza Torricelli 2
56100 Pisa
Université Libre de Bruxelles
Belgium
Address
50,Avenue Franklin Roosevelt
1050 Bruxelles