European Facility For Airborne Research

European Facility For Airborne Research May 24, 2017, 06:10

Document

Description
Title Airborne DOAS measurements in Arctic: vertical distributions of aerosol extinction coefficient and NO2 concentration
Type Publication
Abstract:

We report on airborne Differential Optical Absorption Spectroscopy (DOAS) measurements of aerosol extinction and NO2 tropospheric profiles performed off the North coast of Norway in April 2008. The DOAS instrument was installed on the Safire ATR-42 aircraft during the POLARCAT-France spring campaign and recorded scattered light spectra in near-limb geometry using a scanning telescope. We use O4 slant column measurements to derive the aerosol extinction at 360 nm. Regularization is based on the maximum a posteriori solution, for which we compare a linear and a logarithmic approach. The latter inherently constrains the solution to positive values and yields aerosol extinction profiles more consistent with independently measured size distributions. We present results from two soundings performed on 8 April 2008 above 71° N, 22° E and on 9 April 2008 above 70° N, 17.8° E. The first profile shows aerosol extinction and NO2 in the marine boundary layer with respective values of 0.04 ± 0.005 km−1 and 1.9 ± 0.3 × 109 molec cm−3. A second extinction layer of 0.01 ± 0.003 km−1 is found at 4 km altitude where the NO2 concentration is 0.32 ± 0.2 × 109 molec cm−3. During the second sounding, clouds prevent retrieval of profile parts under 3 km altitude but a layer with enhanced extinction (0.025 ± 0.005 km−1) and NO2 (1.95 ± 0.2 × 109 molec cm−3) is clearly detected at 4 km altitude.
From CO and ozone in-situ measurements complemented by back-trajectories, we interpret the measurements in the free troposphere as, for the first sounding, a mix between stratospheric and polluted air from Northern Europe and for the second sounding, polluted air from Central Europe containing NO2. Considering the boundary layer measurements of the first flight, modeled source regions indicate closer sources, especially the Kola Peninsula smelters, which can explain the NO2 enhancement not correlated with a CO increase at the same altitude.

Available from http://www.atmos-chem-phys.net/11/9219/2011/acp-11-9219-2011.html
Author
ANCELLET Gerard
FAYT Caroline
MERLAUD Alexis
PELON Jacques
QUENNEHEN Boris
SCHWARZENBOECK Alfons
STOHL Andreas
THEYS Nicolas
M. Van Roozendael, C. Hermans, M. Pommier, J. Burkhart, M. De Mazière
Reference
Journal Atmospheric Chemistry and Physics
Volume 11
Pages 9219-9236
Year 2011
Times cited 0
Institute country Belgium
Type of science
  • Aerosol chemistry and physics
  • Gas chemistry
Field of science
  • Boundary layer
  • Troposphere
File details
Added Jan. 31, 2015, 00:00
Last update March 21, 2016, 15:19
Size 33.7 MB
File name None
Visibility Public
Links with specific subjects
Aircraft

Go to the document list

Back to top
EUFAR
EU

This project has received funding from the European Union's Seventh Framework Programme for research, technological development and demonstration under grant agreement no. 312609

Copyright © 2017 EUFAR All rights reserved.