Atmospheric Measurement Techniques (Mar 2017)
Investigating differences in DOAS retrieval codes using MAD-CAT campaign data
- E. Peters,
- G. Pinardi,
- A. Seyler,
- A. Richter,
- F. Wittrock,
- T. Bösch,
- M. Van Roozendael,
- F. Hendrick,
- T. Drosoglou,
- A. F. Bais,
- Y. Kanaya,
- X. Zhao,
- K. Strong,
- J. Lampel,
- R. Volkamer,
- T. Koenig,
- I. Ortega,
- O. Puentedura,
- M. Navarro-Comas,
- L. Gómez,
- M. Yela González,
- A. Piters,
- J. Remmers,
- Y. Wang,
- T. Wagner,
- S. Wang,
- A. Saiz-Lopez,
- D. García-Nieto,
- C. A. Cuevas,
- N. Benavent,
- R. Querel,
- P. Johnston,
- O. Postylyakov,
- A. Borovski,
- A. Elokhov,
- I. Bruchkouski,
- H. Liu,
- C. Liu,
- Q. Hong,
- C. Rivera,
- M. Grutter,
- W. Stremme,
- M. F. Khokhar,
- J. Khayyam,
- J. P. Burrows
Affiliations
- E. Peters
- Institute of Environmental Physics, University of Bremen, Bremen, Germany
- G. Pinardi
- Royal Belgian Institute for Space Aeronomy (BIRA-IASB), Brussels, Belgium
- A. Seyler
- Institute of Environmental Physics, University of Bremen, Bremen, Germany
- A. Richter
- Institute of Environmental Physics, University of Bremen, Bremen, Germany
- F. Wittrock
- Institute of Environmental Physics, University of Bremen, Bremen, Germany
- T. Bösch
- Institute of Environmental Physics, University of Bremen, Bremen, Germany
- M. Van Roozendael
- Royal Belgian Institute for Space Aeronomy (BIRA-IASB), Brussels, Belgium
- F. Hendrick
- Royal Belgian Institute for Space Aeronomy (BIRA-IASB), Brussels, Belgium
- T. Drosoglou
- Aristotle University of Thessaloniki, Thessaloniki, Greece
- A. F. Bais
- Aristotle University of Thessaloniki, Thessaloniki, Greece
- Y. Kanaya
- Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokohama, Japan
- X. Zhao
- Department of Physics, University of Toronto, Ontario, Canada
- K. Strong
- Department of Physics, University of Toronto, Ontario, Canada
- J. Lampel
- Institute of Environmental Physics, University of Heidelberg, Heidelberg, Germany
- R. Volkamer
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA
- T. Koenig
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA
- I. Ortega
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA
- O. Puentedura
- National Institute for Aerospace technology, INTA, Madrid, Spain
- M. Navarro-Comas
- National Institute for Aerospace technology, INTA, Madrid, Spain
- L. Gómez
- National Institute for Aerospace technology, INTA, Madrid, Spain
- M. Yela González
- National Institute for Aerospace technology, INTA, Madrid, Spain
- A. Piters
- Royal Netherlands Meteorological Institute (KNMI), De Bilt, the Netherlands
- J. Remmers
- Max Planck Institute for Chemistry, Mainz, Germany
- Y. Wang
- Max Planck Institute for Chemistry, Mainz, Germany
- T. Wagner
- Max Planck Institute for Chemistry, Mainz, Germany
- S. Wang
- Department of Atmospheric Chemistry and Climate, Institute of Physical Chemistry Rocasolano, CSIC, Madrid, Spain
- A. Saiz-Lopez
- Department of Atmospheric Chemistry and Climate, Institute of Physical Chemistry Rocasolano, CSIC, Madrid, Spain
- D. García-Nieto
- Department of Atmospheric Chemistry and Climate, Institute of Physical Chemistry Rocasolano, CSIC, Madrid, Spain
- C. A. Cuevas
- Department of Atmospheric Chemistry and Climate, Institute of Physical Chemistry Rocasolano, CSIC, Madrid, Spain
- N. Benavent
- Department of Atmospheric Chemistry and Climate, Institute of Physical Chemistry Rocasolano, CSIC, Madrid, Spain
- R. Querel
- National Institute of Water and Atmospheric Research (NIWA), Lauder, New Zealand
- P. Johnston
- National Institute of Water and Atmospheric Research (NIWA), Lauder, New Zealand
- O. Postylyakov
- A. M. Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences, Moscow, Russia
- A. Borovski
- A. M. Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences, Moscow, Russia
- A. Elokhov
- A. M. Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences, Moscow, Russia
- I. Bruchkouski
- National Ozone Monitoring Research and Education Center BSU (NOMREC BSU), Belarusian State University (BSU), Minsk, Belarus
- H. Liu
- School of Earth and Space Sciences, University of Science and Technology of China, Hefei, 230026, China
- C. Liu
- School of Earth and Space Sciences, University of Science and Technology of China, Hefei, 230026, China
- Q. Hong
- Key Lab of Environmental Optics & Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei, 230031, China
- C. Rivera
- Facultad de Química, Universidad Nacional Autónoma de México, Mexico City, Mexico
- M. Grutter
- Centro de Ciencias de la Atmósfera, Universidad Nacional Autónoma de México, Mexico City, Mexico
- W. Stremme
- Centro de Ciencias de la Atmósfera, Universidad Nacional Autónoma de México, Mexico City, Mexico
- M. F. Khokhar
- Institute of Environmental Sciences and Engineering (IESE), National University of Sciences and Technology (NUST) Islamabad, Islamabad, Pakistan
- J. Khayyam
- Institute of Environmental Sciences and Engineering (IESE), National University of Sciences and Technology (NUST) Islamabad, Islamabad, Pakistan
- J. P. Burrows
- Institute of Environmental Physics, University of Bremen, Bremen, Germany
- DOI
- https://doi.org/10.5194/amt-10-955-2017
- Journal volume & issue
-
Vol. 10,
no. 3
pp. 955 – 978
Abstract
The differential optical absorption spectroscopy (DOAS) method is a well-known remote sensing technique that is nowadays widely used for measurements of atmospheric trace gases, creating the need for harmonization and characterization efforts. In this study, an intercomparison exercise of DOAS retrieval codes from 17 international groups is presented, focusing on NO2 slant columns. The study is based on data collected by one instrument during the Multi-Axis DOAS Comparison campaign for Aerosols and Trace gases (MAD-CAT) in Mainz, Germany, in summer 2013. As data from the same instrument are used by all groups, the results are free of biases due to instrumental differences, which is in contrast to previous intercomparison exercises.While in general an excellent correlation of NO2 slant columns between groups of > 99.98 % (noon reference fits) and > 99.2 % (sequential reference fits) for all elevation angles is found, differences between individual retrievals are as large as 8 % for NO2 slant columns and 100 % for rms residuals in small elevation angles above the horizon.Comprehensive sensitivity studies revealed that absolute slant column differences result predominantly from the choice of the reference spectrum while relative differences originate from the numerical approach for solving the DOAS equation as well as the treatment of the slit function. Furthermore, differences in the implementation of the intensity offset correction were found to produce disagreements for measurements close to sunrise (8–10 % for NO2, 80 % for rms residual). The largest effect of ≈ 8 % difference in NO2 was found to arise from the reference treatment; in particular for fits using a sequential reference. In terms of rms fit residual, the reference treatment has only a minor impact. In contrast, the wavelength calibration as well as the intensity offset correction were found to have the largest impact (up to 80 %) on rms residual while having only a minor impact on retrieved NO2 slant columns.
