03 Aug 2021

03 Aug 2021

Review status: a revised version of this preprint is currently under review for the journal AMT.

Validation and Error Estimation of AIRS MUSES CO Profiles with HIPPO, ATom and NOAA GML Aircraft Observations

Jennifer D. Hegarty1, Karen E. Cady-Pereira1, Vivienne H. Payne2, Susan S. Kulawik3, John R. Worden2, Valentin Kantchev2,4, Helen M. Worden5, Kathryn McKain6,7, Jasna V. Pittman8,9, Róisín Commane10, Bruce C. Daube Jr.8,9, and Eric A. Kort11 Jennifer D. Hegarty et al.
  • 1Atmospheric and Environmental Research Inc., Lexington, Massachusetts, USA
  • 2Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
  • 3BAER Institute, 625 2nd Street, Suite 209, Petaluma, CA, USA
  • 4Instrument Software and Science Data Systems, Pasadena, CA, USA
  • 5Atmospheric Chemistry Observations and Modeling Laboratory, National Center for Atmospheric Research, Boulder, CO, USA
  • 6Earth System Research Laboratory, National Oceanic and Atmospheric Administration, Boulder, CO, USA
  • 7Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
  • 8School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
  • 9Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA, USA
  • 10Department of Earth and Environmental Science, Lamont-Doherty Earth Observatory, Columbia University, New York, NY, USA
  • 11Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI, USA

Abstract. Single footprint retrievals of carbon monoxide from the Atmospheric Infrared Sounder (AIRS) are evaluated using aircraft in situ observations. The aircraft data are from the HIAPER Pole-to-Pole (HIPPO, 2009–2011), the first three Atmospheric Tomography Mission (ATom, 2016–2017) campaigns and the National Oceanic and Atmospheric Administration (NOAA) Global Monitoring Laboratory (GML) Global Greenhouse Gas Reference Network Aircraft Program from 2006–2017. The retrievals are obtained using an optimal estimation approach within the MUlti-SpEctra, MUlti-SpEcies, MUlti-Sensors (MUSES) algorithm. Retrieval biases and estimated errors are evaluated across a range of latitudes from the sub-polar to tropical regions over both ocean and land points.

AIRS MUSES CO profiles were compared with HIPPO, ATom, and NOAA GML aircraft observations with a coincidence of 9 hours and 50 km to estimate retrieval biases and standard deviations. Comparisons were done for different pressure levels and column averages, latitudes, day, night, land, and ocean observations. We find mean biases of +6.6 % +/− 4.6 %, +0.6 % +/− 3.2 %, −6.1 % +/− 3.0 %, and 1.4 % +/− 3.6 %, for 750 hPa, 510 hPa, 287 hPa, and the column averages, respectively. The mean standard deviation is 15 %, 11 %, 12 %, and 9 % at these same pressure levels, respectively. Observation errors (theoretical errors) from the retrievals were found to be broadly consistent in magnitude with those estimated empirically from ensembles of satellite aircraft comparisons. The GML Aircraft Program comparisons generally had higher standard deviations and biases than the HIPPO and ATom comparisons. Since the GML aircraft flights do not go as high as the HIPPO and ATom flights, results from these GML comparisons are more sensitive to the choice of method for extrapolation of the aircraft profile above the uppermost measurement altitude. The AIRS retrieval performance shows little sensitivity to surface type (land or ocean) or day or night but some sensitivity to latitude. Comparisons to the NOAA GML set spanning the years 2006–2017 show that the AIRS retrievals are able to capture the distinct seasonal cycles but show a high bias of ~20 % in the lower troposphere during the summer when observed CO mixing ratios are at annual minimum values. The retrieval bias drift was examined over the same period and found to be small at < 0.5 % over the 2006–2017 time period.

Jennifer D. Hegarty et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on amt-2021-211', Anonymous Referee #1, 23 Aug 2021
    • AC1: 'Reply on RC1', Jennifer Hegarty, 04 Oct 2021
  • RC2: 'Comment on amt-2021-211', Anonymous Referee #2, 03 Sep 2021
    • AC2: 'Reply on RC2', Jennifer Hegarty, 04 Oct 2021

Jennifer D. Hegarty et al.

Jennifer D. Hegarty et al.


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Short summary
We compared estimates of atmospheric carbon monoxide (CO) derived from outgoing radiation measurements of the Atmospheric Infrared Sounder on a satellite orbiting the Earth to CO measurements made from aircraft. CO produced by combustion of substances such as fossil fuels plays an important role in atmospheric pollution and climate. Satellites measurements provide continuous monitoring over large spatial areas but must be checked against other types of measurements to ensure validity