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JOURNAL OF GEOPHYSICAL RESEARCH,
VOL. 109,
D14304,
doi:10.1029/2003JD004463,
2004
Retrieved tropospheric and stratospheric BrO columns over Lauder, New Zealand
R. Schofield
National Institute of Water and Atmospheric Research, Omakau, Central Otago, New Zealand
K. Kreher
National Institute of Water and Atmospheric Research, Omakau, Central Otago, New Zealand
B. J. Connor
National Institute of Water and Atmospheric Research, Omakau, Central Otago, New Zealand
P. V. Johnston
National Institute of Water and Atmospheric Research, Omakau, Central Otago, New Zealand
A. Thomas
National Institute of Water and Atmospheric Research, Omakau, Central Otago, New Zealand
D. Shooter
School of Geography and Environmental Science, University of Auckland, Auckland, New Zealand
M. P. Chipperfield
School of the Environment, University of Leeds, Leeds, UK
C. D. Rodgers
Atmospheric, Oceanic and Planetary Physics, Clarendon Laboratory, University of Oxford, Oxford, UK
G. H. Mount
Laboratory for Atmospheric Research, Washington State University, Pullman, Washington, USA
Abstract
Spectroscopic measurements of BrO using direct sun and zenith-sky viewing geometries are combined in an optimal estimation
retrieval algorithm to obtain tropospheric and stratospheric columns of BrO. Seventy-two twilight periods are investigated
over Lauder, New Zealand (45.0°S, 169.7°E), between March 2001 and April 2003. A direct comparison between tropospheric and
stratospheric columns retrieved at 80°, 84°, and 87° solar zenith angles (SZAs) from the spectroscopic measurements and those
calculated by the three-dimensional chemical transport model SLIMCAT shows good agreement. The stratospheric Bry loading of 21 pptv from the SLIMCAT calculations is consistent with the ground-based measurements. The seasonal and diurnal
variation of the stratospheric BrO columns evident from the ground-based measurement retrievals is well described by the SLIMCAT
model. The tropospheric column retrievals illustrate a high variability with a mean value of 0.2 pptv if the troposphere is
assumed to be well mixed. An upper limit of 0.9 pptv is established for the ubiquitous BrO tropospheric column at 80° under
cloud free conditions.
Received 18
December
2003;
accepted 19
April
2004;
published 30
July
2004.
Keywords: remote sensing;
bromine;
troposphere;
retrieval;
diurnal variation.
Index Terms: 0341 Atmospheric Composition and Structure: Middle atmosphere—constituent transport and chemistry (3334); 0365 Atmospheric Composition and Structure: Troposphere—composition and chemistry; 0394 Atmospheric Composition and Structure: Instruments and techniques.
Read Full Article (file size: 867199 bytes) Cited by
Citation: Schofield, R., K. Kreher, B. J. Connor, P. V. Johnston, A. Thomas, D. Shooter, M. P. Chipperfield, C. D. Rodgers, and G. H. Mount
(2004),
Retrieved tropospheric and stratospheric BrO columns over Lauder, New Zealand,
J. Geophys. Res.,
109,
D14304,
doi:10.1029/2003JD004463.
Copyright 2004 by the American Geophysical Union.
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