Diurnal variation of stratospheric and lower mesospheric HOCl, ClO and HO2 at the equator: comparison of 1-D model calculations with measurements by satellite instruments
Artikel i vetenskaplig tidskrift, 2013

The diurnal variation of HOCl and the related species ClO, HO2 and HCl measured by satellites has been compared with the results of a one-dimensional photochemical model. The study compares the data from various limb-viewing instruments with model simulations from the middle stratosphere to the lower mesosphere. Data from three sub-millimetre instruments and two infrared spectrometers are used, namely from the Sub-Millimetre Radiometer (SMR) on board Odin, the Microwave Limb Sounder (MLS) on board Aura, the Superconducting Submillimeter-wave Limb-Emission Sounder (SMILES) on the International Space Station, the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) on board ENVISAT, and the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) on board SCISAT. Inter-comparison of the measurements from instruments on sun-synchronous satellites (SMR, MLS, MIPAS) and measurements from solar occultation instruments (ACE-FTS) is challenging since the measurements correspond to different solar zenith angles (or local times). However, using a model which covers all solar zenith angles and data from the SMILES instrument which measured at all local times over a period of several months provides the possibility to verify the model and to indirectly compare the diurnally variable species. The satellite data were averaged for latitudes of 20 degrees S to 20 degrees N for the SMILES observation period from November 2009 to April 2010 and were compared at three altitudes: 35, 45 and 55 km. Besides presenting the SMILES data, the study also shows a first comparison of the latest MLS data (version 3.3) of HOCl, ClO, and HO2 with other satellite observations, as well as a first evaluation of HO2 observations made by Odin/SMR. The MISU-1D model has been carefully initialised and run for conditions and locations of the observations. The diurnal cycle features for the species investigated here are generally well reproduced by the model. The satellite observations and the model agree well in terms of absolute mixing ratios. The differences between the day and night values of the model are in good agreement with the observations although the amplitude of the HO2 diurnal variation is 10-20 % lower in the model than in the observations. In particular, the data offered the opportunity to study the reaction ClO+HO2 -> HOCl+O-2 in the lower mesosphere at 55 km. At this altitude the HOCl night-time variation depends only on this reaction. The result of this analysis points towards a value of the rate constant within the range of the JPL 2006 recommendation and the upper uncertainty limit of the JPL 2011 recommendation at 55 km.

stratosphere

diurnal variation

HOCl

short-lived species

HO2

ClO

Författare

Maryam Khosravi

Chalmers, Rymd- och geovetenskap, Global miljömätteknik och modellering

P. Baron

Japan National Institute of Information and Communications Technology

Joachim Urban

Chalmers, Rymd- och geovetenskap, Global miljömätteknik och modellering

L. Froidevaux

Jet Propulsion Laboratory, California Institute of Technology

A. I. Jonsson

University of Toronto

Y. Kasai

Tokyo Institute of Technology

Japan National Institute of Information and Communications Technology

K. Kuribayashi

Tokyo Institute of Technology

Japan National Institute of Information and Communications Technology

C. Mitsuda

Fujitsu FTP Corporation

Donal Murtagh

Chalmers, Rymd- och geovetenskap, Global miljömätteknik och modellering

H. Sagawa

Japan National Institute of Information and Communications Technology

M. L. Santee

Jet Propulsion Laboratory, California Institute of Technology

T. O. Sato

Tokyo Institute of Technology

Japan National Institute of Information and Communications Technology

M. Shiotani

Kyoto University

M. Suzuki

JAXA Institute of Space and Astronautical Science

T. von Clarmann

Karlsruher Institut für Technologie (KIT)

K. A. Walker

University of Toronto

S. Wang

Jet Propulsion Laboratory, California Institute of Technology

Atmospheric Chemistry and Physics

1680-7316 (ISSN) 1680-7324 (eISSN)

Vol. 13 15 7587-7606

Ämneskategorier

Meteorologi och atmosfärforskning

DOI

10.5194/acp-13-7587-2013

Mer information

Senast uppdaterat

2018-09-06