Tropical Tropospheric Ozone Trends (1990 to 2020) From Updated SHADOZ Profiles and Satellite Data

The Southern Hemisphere Additional Ozonesondes (SHADOZ) network archives ozonesonde-radiosonde data records for 14 tropical and subtropical stations with ~10,000 ozone profiles from 1998 to 2023 at the SHADOZ archive (https://tropo.gsfc.nasa.gov/shadoz/Archive.html). The success of SHADOZ is thanks to the 25-year partnerships between NASA/GSFC, NOAA’s Global Monitoring Lab and international collaborators and their dedication in providing the highest quality ozonesonde data for ozone trends studies. We present updates on: (1) Reprocessing of selected SHADOZ data to correct for artifact low stratospheric ozone (Stauffer et al., 2022) caused by unexpected instrument changes; the method used is described by Nakano and Morofuji (2023). (2) Free tropospheric (FT) ozone trends based on equatorial SHADOZ data, updated from Thompson et al. (2021) which found considerable seasonal and regional variability with negligible to small increases from 1998 to 2019. (3) FT ozone trends computed using profiles from SHADOZ stations taken prior to SHADOZ start (1990-2020). The corresponding column amounts are compared to satellite data and IAGOS aircraft profiles and columns. The satellite products are from the TOMS and OMI cloud-slicing (“CCD”; 1990-2020) and OMI/MLS (2005-2020) products and are based on NASA/GSFC v9 TOMS and OMI data. Our analysis provides guidance on using satellite (continuous, global, ~10-20% uncertainty) and profile (high-resolution, 3-5% precision but less frequent) observations to study tropical FT ozone changes. As part of the TOAR II/HEGIFTOM activity, our SHADOZ data continue to be a model for the highest quality ozone data.

References

Nakano, T. and Morofuji, T. (2023), Atmos. Meas. Tech., 16, 1583–1595, https://doi.org/10.5194/amt-16-1583-2023.

Stauffer, R. M., Thompson, A. M., Kollonige, D. E., et al. (2022). Earth and Space Science, 9, e2022EA002459. https://doi.org/10.1029/2022EA002459.

Thompson, A. M., Stauffer, R. M., et al. (2021) Journal of Geophysical Research: Atmospheres, 126, e2021JD034691, https://doi.org/10.1029/2021JD034691.