The Level 2 research product algorithms for the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES)
Journal article, 2011
This paper describes the algorithms of the level 2 research (L2r) processing chain developed for the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES). The chain has been developed in parallel to the operational chain for conducting researches on calibration and retrieval algorithms. L2r chain products are available to the scientific community. The objective of version 2 is the retrieval of the vertical distribution of trace gases in the altitude range of 18-90 km. A theoretical error analysis is conducted to estimate the retrieval feasibility of key parameters of the processing: line-of-sight elevation tangent altitudes (or angles), temperature and ozone profiles. While pointing information is often retrieved from molecular oxygen lines, there is no oxygen line in the SMILES spectra, so the strong ozone line at 625.371GHz has been chosen. The pointing parameters and the ozone profiles are retrieved from the line wings which are measured with high signal to noise ratio, whereas the temperature profile is retrieved from the optically thick line center. The main systematic component of the retrieval error was found to be the neglect of the non-linearity of the radiometric gain in the calibration procedure. This causes a temperature retrieval error of 5-10 K. Because of these large temperature errors, it is not possible to construct a reliable hydrostatic pressure profile. However, as a consequence of the retrieval of pointing parameters, pressure induced errors are significantly reduced if the retrieved trace gas profiles are represented on pressure levels instead of geometric altitude levels. Further, various setups of trace gas retrievals have been tested. The error analysis for the retrieved HOCl profile demonstrates that best results for inverting weak lines can be obtained by using narrow spectral windows.
Author
P. Baron
Japan National Institute of Information and Communications Technology
Joachim Urban
Chalmers, Earth and Space Sciences, Global Environmental Measurements and Modelling
H. Sagawa
Japan National Institute of Information and Communications Technology
J. Möller
Chalmers University of Technology
Donal Murtagh
Chalmers, Earth and Space Sciences, Global Environmental Measurements and Modelling
J. Mendrok
Lulea tekniska Universitet
E. Dupuy
Japan National Institute of Information and Communications Technology
T. O. Sato
Tokyo Institute of Technology
Japan National Institute of Information and Communications Technology
S. Ochiai
Japan National Institute of Information and Communications Technology
K. Suzuki
Japan National Institute of Information and Communications Technology
T. Manabe
Osaka Prefecture University
T. Nishibori
Japan Aerospace Exploration Agency
K. Kikuchi
Japan National Institute of Information and Communications Technology
Japan Aerospace Exploration Agency
R. Sato
Japan Aerospace Exploration Agency
Masahiro Takayanagi
Japan Aerospace Exploration Agency
Y. Murayama
Japan National Institute of Information and Communications Technology
M. Shiotani
Kyoto University
Y. Kasai
Japan National Institute of Information and Communications Technology
Atmospheric Measurement Techniques
1867-1381 (ISSN) 1867-8548 (eISSN)
Vol. 4 10 2105-2124Driving Forces
Sustainable development
Subject Categories (SSIF 2011)
Meteorology and Atmospheric Sciences
Earth and Related Environmental Sciences
DOI
10.5194/amt-4-2105-2011