EGU21-13634
https://doi.org/10.5194/egusphere-egu21-13634
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

The importance of the time response of Electrochemical Concentration Cell (ECC) ozone sondes for measurements of tropical upper tropospheric and lower stratospheric ozone

Holger Vömel1, Ryan Stauffer2, Henry Selkirk3, Anne Thompson4, Jorge Andres Diaz5, Debra Kollonige6, Ernesto Corrales5, and Alfredo Alan5
Holger Vömel et al.
  • 1NCAR, EOL, Boulder, CO, USA (voemel@ucar.edu)
  • 2Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, USA
  • 3Science Mission Directorate, NASA, Washington, DC, USA
  • 4Atmospheric Chemistry and Dynamics Lab, NASA/GSFC, Greenbelt, MD, USA
  • 5GasLab, CICANUM, University of Costa Rica, San Jose, Costa Rica
  • 6Science Systems and Applications, Inc., Lanham, MD, USA

Accurate measurements of ozone in the upper tropical troposphere and lower stratosphere (UTLS) are challenging for most measuring systems, yet of great importance for the understanding of the chemical and dynamical processes in this region.

Balloon-borne observations using Electrochemical Concentration Cell (ECC) ozone sondes are the most widely used in situ technology to measure vertical profiles of ozone in networks such as the Southern Hemisphere ADditional Ozonesondes (SHADOZ) network of tropical and subtropical ozone sonde stations.

The tropical upper troposphere and the layers of near-zero ozone within the ozone hole are most sensitive to processing and preparation variations that may affect the accuracy and possibly trend estimates of ozone in low ozone regions. It is now appreciated that the complex chemistry within the ECC used to detect ozone exhibits two different time constants (τfast≈20 s, τslow≈25 min), which modify the response of the ECC during a profile. Although not well understood, the chemistry of the slow reaction is likely to represent what has conventionally been assumed a constant “background current”. The fast reaction causes some delay in the response of the ECC to changes in the vertical profile of ozone. Here we show how correcting for both improves the estimate of the lowest ozone concentration in the upper troposphere as well as the steepness of the gradient in the transition into the stratosphere. The steady state bias, which describes the contribution of the slow reaction, is the largest source of uncertainty overall; the response time of the fast reaction dominates the uncertainty in the region of the sharp gradient of ozone above the tropopause.

How to cite: Vömel, H., Stauffer, R., Selkirk, H., Thompson, A., Diaz, J. A., Kollonige, D., Corrales, E., and Alan, A.: The importance of the time response of Electrochemical Concentration Cell (ECC) ozone sondes for measurements of tropical upper tropospheric and lower stratospheric ozone, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-13634, https://doi.org/10.5194/egusphere-egu21-13634, 2021.

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