Preprints
https://doi.org/10.5194/amt-2021-300
https://doi.org/10.5194/amt-2021-300

  05 Nov 2021

05 Nov 2021

Review status: this preprint is currently under review for the journal AMT.

The SPARC water vapor assessment II: Assessment of satellite measurements of upper tropospheric water vapor

William G. Read1, Gabriele Stiller2, Stefan Lossow2, Michael Kiefer2, Farahnaz Khosrawi2, Dale Hurst3, Holger Vömel4, Karen Rosenlof5, Bianca M. Dinelli6, Piera Raspollini7, Gerald E. Nedoluha8, John C. Gille9,10, Yasuko Kasai11, Patrick Eriksson12, Chistopher E. Sioris13, Kaley A. Walker14, Katja Weigel15, John P. Burrows15, and Alexei Rozanov15 William G. Read et al.
  • 1Jet Propulsion Laboratory, California Institute of Technology, Pasadena, Ca., USA
  • 2Karlsruhe Institute of Technology, Institute of Meteorology and Climate Research, Karlsruhe, Germany
  • 3Global Monitoring Division, NOAA, Earth System Research Laboratory, Boulder, Colorado, USA
  • 4Earth Observing Laboratory, National Center for Atmospheric Research, Boulder, Colorado, USA
  • 5Chemical Science Division, NOAA, Earth System Research Laboratory, Boulder, Colorado, USA
  • 6Instituto di Scienze dell’Atmosfera e del Clima del Consiglio Nazionale delle Ricerche (ISAC-CNR), Via Gobetti, 101, 40129 Bologna, Italy
  • 7Instituto di Fisica Applicata del Consiglio Nazionale delle Ricerche (IFAC-CNR), Via Madonna del Piano, 10, 50019 Sesto Fiorentino, Italy
  • 8Naval Research Laboratory, Remote Sensing Division, 4555 Overlook Avenue Southwest, Washington, DC 20375, USA
  • 9National Center for Atmospheric Research, Atmospheric Chemistry Observations & Modeling Laboratory, P.O. Box 3000, Boulder, CO. 80307-3000, USA
  • 10University of Colorado, Atmospheric and Oceanic Sciences, Boulder, CO 80309-0311, USA
  • 11National Institute of Information and Communications Technology (NICT), 20 THz Research Center, 4-2-1 Nukui-kita, Koganei, Tokyo 184–8795, Japan
  • 12Chalmers University of Technology, Department of Space, Earth and Environment, Hörsalsvägen 11, 41296 Göteborg, Sweden
  • 13York University, Center for Research in Earth and Space Science, 4700 Keele Street, Toronto, Ontario M3J 1P3, Canada
  • 14University of Toronto, Department of Physics, 60 St. George Street, Toronto, Ontario M5S 1A7, Canada
  • 15University of Bremen, Institute of Environmental Physics, Otto-Hahn-Allee 1, 28334 Breman, Germany

Abstract. Nineteen limb viewing (occultation and passive thermal) and two nadir humidity data sets are intercompared and also compared to frostpoint hygrometer balloon sondes. The upper troposphere considered here covers the pressure range from 300–100 hPa. Water vapor in this region is a challenging measurement because concentrations vary between 2–1000 parts per million volume with sharp changes in vertical gradients near the tropopause. The atmospheric temperature is also highly variable ranging from 180–250 K. The assessment of satellite measured humidity is based on coincident comparisons with frostpoint hygrometer sondes, multi month mapped comparisons, zonal mean time series comparisons and coincident satellite to satellite comparisons. While the satellite fields show similar features in maps and time series, quantitatively, they can differ by a factor of two in concentration, with strong dependencies on the amount of H2O. Additionally, time-lag response corrected Vaisala-RS92 radiosondes are compared to satellites and the frostpoint hygrometer measurements. In summary, most satellite data sets reviewed here show on average ~30 % agreement amongst themselves and frostpoint data but with an additional ~30 % variability about the mean. The Vaisala-RS92 sonde even with a time-lag correction shows poor behavior for pressure less than 200 hPa.

William G. Read et al.

Status: open (until 13 Dec 2021)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Review of “The SPARC water vapor assessment II: Assessment of satellite measurements of upper tropospheric water vapor” by William Read et al.', Anonymous Referee #1, 30 Nov 2021 reply
  • RC2: 'Comment on amt-2021-300', Anonymous Referee #2, 07 Dec 2021 reply

William G. Read et al.

William G. Read et al.

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Short summary
This paper attempts to provide an assessment of the accuracy of 21 satellite based instruments that remotely measure atmospheric humidity in the upper troposphere of the Earth's atmosphere. The instruments made their measurements from 1984 to the present time; however, most of these instruments began operations after 2000 and only a few are still operational. The objective of this study is to quantify the accuracy of each satellite humidity data set.