Journal cover Journal topic
Atmospheric Measurement Techniques An interactive open-access journal of the European Geosciences Union
Journal topic

Journal metrics

IF value: 3.668
IF3.668
IF 5-year value: 3.707
IF 5-year
3.707
CiteScore value: 6.3
CiteScore
6.3
SNIP value: 1.383
SNIP1.383
IPP value: 3.75
IPP3.75
SJR value: 1.525
SJR1.525
Scimago H <br class='widget-line-break'>index value: 77
Scimago H
index
77
h5-index value: 49
h5-index49
Preprints
https://doi.org/10.5194/amt-2020-62
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/amt-2020-62
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

  06 Apr 2020

06 Apr 2020

Review status
A revised version of this preprint was accepted for the journal AMT and is expected to appear here in due course.

A new method to correct the ECC ozone sonde time response and its implications for “background current” and pump efficiency

Holger Vömel1, Herman G. J. Smit2, David Tarasick3, Bryan Johnson4, Samuel J. Oltmans4, Henry Selkirk5, Anne M. Thompson6, Ryan M. Stauffer6, Jacquelyn C. Witte1, Jonathan Davies3, Roeland van Malderen7, Gary A. Morris8, Tatsumi Nakano9, and Rene Stübi10 Holger Vömel et al.
  • 1National Center for Atmospheric Research, Boulder, CO, 30301, USA
  • 2Research Center Jülich, Germany
  • 3Environment Canada, Downsview, ON, Canada
  • 4National Oceanic and Atmospheric Administration, Boulder, CO, 30305, USA
  • 5University Space Research Associates, Greenbelt, Maryland, USA
  • 6NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
  • 7Royal Meteorological Institute, Brussels, Belgium
  • 8St. Edward’s University, Austin, TX, USA
  • 9Japan Meteorological Agency, Tokyo, Japan
  • 10MeteoSwiss Aerological Station, Payerne, Switzerland

Abstract. The Electrochemical Concentration Cell (ECC) ozonesonde has been the main instrument for in situ profiling of ozone worldwide; yet, some details of its operation, which contribute to the ozone uncertainty budget, are not well understood. Here, we investigate the time response of the chemical reactions inside the ECC and how corrections can be used to remove some systematic biases. The analysis is based on the understanding that two reaction pathways involving ozone occur inside the ECC that generate electrical currents on two very different time scales. A slow reaction pathway involving the buffer with a time constant of about 25 min can be interpreted as what has conventionally been considered the “background current”. This contribution can be calculated and removed from the measured current instead of the “background current”. The remaining fast reaction pathway with a time constant of about 20 s is due the conversion of iodide to molecular iodine and the generation of two free electrons per ozone molecule. Here we provide an algorithm to calculate and remove the contribution of the slow reaction pathway and to correct for the time lag of the faster reaction pathway.

This processing algorithm has been applied to ozonesonde profiles at Costa Rica and during the Central Equatorial Pacific Experiment (CEPEX) and to laboratory experiments evaluating the performance of ECC ozonesondes. At Costa Rica, where a 1 % KI, 1/10th buffer solution is used, there is no change in the derived total ozone column; however, in the upper troposphere and lower stratosphere, average reported ozone concentrations increase by up to 7 % and above 30 km decrease by up to 7 %. During CEPEX, where a 1 % KI, full buffer solution was used, ozone concentrations are increased mostly in the upper troposphere with no change near to the top of the profile. In the laboratory measurements, the processing algorithms have been applied to measurements using all current sensing solutions and using only the stronger pump efficiency correction reported by Johnson et al. (2002), which improves the time response of the ECCs and removes some biases relative to the reference instruments.

In the surface layer, the correction algorithm shows that ECC ozonesonde measurements are influenced by the operational procedures prior to launch and that typical gradients above the surface layer may be steeper than originally reported.

Holger Vömel et al.

Interactive discussion

Status: closed
Status: closed
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
Printer-friendly Version - Printer-friendly version Supplement - Supplement

Interactive discussion

Status: closed
Status: closed
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
Printer-friendly Version - Printer-friendly version Supplement - Supplement

Holger Vömel et al.

Holger Vömel et al.

Viewed

Total article views: 354 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
274 72 8 354 10 9
  • HTML: 274
  • PDF: 72
  • XML: 8
  • Total: 354
  • BibTeX: 10
  • EndNote: 9
Views and downloads (calculated since 06 Apr 2020)
Cumulative views and downloads (calculated since 06 Apr 2020)

Viewed (geographical distribution)

Total article views: 284 (including HTML, PDF, and XML) Thereof 282 with geography defined and 2 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 

Cited

Saved

No saved metrics found.

Discussed

No discussed metrics found.
Latest update: 20 Sep 2020
Publications Copernicus
Download
Short summary
The time response of Electrochemical Concentration Cell (ECC) ozone sondes points to at least two distinct reaction pathways with time constants of approximately 20 s and 25 min. Properly considering these time constants eliminates the need for a poorly defined "background" and allows reducing ad-hoc corrections based on laboratory tests. This reduces the uncertainty of ECC ozone sonde measurements throughout the profile and especially in regions of low ozone and strong gradients of ozone.
The time response of Electrochemical Concentration Cell (ECC) ozone sondes points to at least...
Citation