American Geophysical Union Become an AGU Member
Subscribe to AGU Journals		 AGU Home AGU Publications

Read Full Article (file size: 867199 bytes)    Cited by

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.