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Aerosol, polar stratospheric cloud, and chemical composition measurements in the mountain lee wave region at the arctic circle in western Scandinavia during SESAME

Objective

The main objective of this project is to perform field measurements of chemical species and aerosols at high latitudes yielding data which help to test the present understanding on how polar stratospheric clouds and (volcanic) aerosols affect the nitrogen and chlorine partitioning.


Particulate measurements will be performed by lidar, one ground-based at Andøya (69.3°N, 16.0°E) and one airborne with the aircraft stationed at Kiruna (67.9°N, 21.1°E) during SESAME. The lidar measurements will show the presence of aerosols and the vertical distribution. In the case of LEANDRE lidar the horizontal scales can be determined, while the Andøya lidar measures the temporal evolution at a fixed location. Polarization and two colour measurements will delineate the particulate shape, i.e. its physical phase, and distribution changes, which can be used to identify spherical PSCs among sulfur acid droplets.

Composition measurements will be performed by two ground-based spectrometers at Kiruna. One of the instruments is a differential absorption spectrometer (DOAS) using zenith scattering, off-axis solar scattering or direct moonlight observation geometries. The other instrument is a Fourier transform spectrometer (FTIR) operated in solar occultation geometry. The primary quantities derived will be zenith column amounts of various trace gases, among them NO2, NO3, CIONO2 and HNO3, which are involved in the nitrogen partitioning scheme. In addition other gases of relevance to the ozone depletion problem are measured. They include O3, HCI, BrO, OCIO, CFC12, CH4, H2O and HDO. For some of these gases, the tropospheric and stratospheric contributions can be separated or even an altitude profile derived. The techniques used are based on measurements at several zenith angles (DOAS) or exploit the high spectral resolution (FTIR). Also, it is possible for the DOAS to detect changes in the sky colour during twilight which may be attributed to polar sstratospheric clouds above the station.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

RHEINISCHE FRIEDRICH-WILHELMS-UNIVERSITÄT BONN
Address
Nussallee 12
Bonn
Germany

Participants (4)

CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE
France
Address
Route Des Gètines
92371 Verrieres-le-buisson
Forschungszentrum Karlsruhe Technik und Umwelt GmbH
Germany
Address
Weberstraße 5
76133 Karlsruhe
RUPRECHT-KARLS-UNIVERSITAET HEIDELBERG
Germany
Address
Im Neuenheimer Feld 229
69117 Heidelberg
UNIVERSITY OF GENEVA
Switzerland
Address
24,Rue General Dufour 24
1211 Geneve