Principal Investigator: Dr. Ryan M. Stauffer (NASA/Goddard Space Flight Center)

Founding Principal Investigator: Dr. Anne M. Thompson (NASA/Goddard Space Flight Center)

A number of ozonesonde stations are operating in the tropics, subtropics, and the southern hemisphere in general, but with differing frequency and reporting procedures. SHADOZ (Southern Hemisphere ADditional OZonesondes) is designed to remedy this data discrepancy, by coordinating launches, supplying additional sondes in some cases, and by providing a central archive location. Since 1998, ozonesonde data have been collected and made available through this website.

Questions regarding sonde data from specific stations should be directed to the stations' principal investigator. A list of PI contact information can be found on the PI CONTACTS link in the banner above.

Exciting News for SHADOZ!!!

Starting in 2025, two stations are joining the SHADOZ network: Quito, Ecuador, and Palau (Tropical West Pacific).

In 2021, ozonesonde launches at the San Cristóbal, Galapagos, Ecuador station resumed and at the same time data from Quito, Ecuador, ozonesonde launches also became available on the SHADOZ archive. Ozonesonde launches began in 2014 at Universidad San Francisco de Quito’s Atmospheric Measurement Station (EMA). For more on the Quito station, see the paper published by Cazorla and Herrera, (2022). Past Quito data (2014-2021) will be available on the Archive soon!

The Palau Atmospheric Observatory, located in the Tropical Western Pacific, initiated ozonesonde launches in 2016 as part of the EU-funded StratoClim (Stratospheric and upper tropospheric processes for better Climate predictions, 2015-2019) project. The measurement site, sponsored by the Alfred Wegener Institute (AWI), launches ozonesondes twice per month. For more information on the observing station, see Müller et al. (2024). New ozonesonde data from 2016-2024 will be available soon on the SHADOZ Archive!

In addition to the two new SHADOZ stations, the Wallops Island, VA, USA, station (operated and maintained by the NASA GSFC SHADOZ team), now has its ozonesonde data in SHADOZ V06 format available on the SHADOZ archive (far right tab above)!

NEW Science with SHADOZ Data in the Tropospheric Ozone Assessment Report (TOAR-II) Special Issue!!

• Stauffer et al. (2024) demonstrated that over a 25-year period (1998-2022), early year free troposphere ozone increases of +10 to 15%/decade are associated with declining convection, most pronounced over the SE Asian stations, Kuala Lumpur and Watukosek. With the latest OMI/MLS-based satellite estimates of tropospheric column ozone, Gaudel et al. (2024) showed that satellite, SHADOZ and IAGOS aircraft profiles were in good agreement over SE Asia, but more divergent over equatorial Americas and Africa. Both papers are now published in the TOAR-II special issue!

• The TOAR-II Working Group Harmonization and Evaluation of Ground-based Instruments for Free-Tropospheric Ozone Measurements (HEGIFTOM) reprocessed ground-based observations with uniform procedures and has provided homogenized public data from 5 networks globally: ozonesondes, aircraft profiles (IAGOS), FTIR spectrometers, Lidars, and Dobson Umkehr measurements.Tropospheric column trends (surface - 300 hPa) are reported for 2000-2022 for 55 individual stations in Van Malderen et al. (2025a) and regionally in a second publication from Van Malderen et al. (2025b). Trends fall within -4 to +8%/decade with the greatest increases over SE Asia as well as the tropics/subtropics (eg. SHADOZ stations - Kuala Lumpur, La Reunion Island) and decreases at northern high latitudes. Both papers serve as a great reference for satellite and model products.

• Thompson et al (2025) extended our Thompson et al (2021; designated "T21") trends for 5 SHADOZ sites, covering 26 years: 1998-2023. (1) Lowermost stratospheric ozone shows no tropopause-referenced changes but -3%/decade at 80 hPa. (2) Tropospheric trends showed little change from T21, (0.5-1 DU/decade in column "TrCO", surface to tropopause) except for SE Asia. (3) For 2005-2023, TrCO_sonde and OMI/MLS TrCO trends agree at 4 of the 5 sites.

  Important TOAR messages: (1) in the free troposphere, combining thousands of IAGOS and SHADOZ profiles yields the same trends as SHADOZ-only. SHADOZ sampling (2-5/month) is sufficient! (2) QR and MLR median annual trends are essentially the same; (3) with the period reduced to 12 years, SHADOZ trends (presumably satellites too) are not reliable for TOAR-II purposes.

We would like to keep a running list of papers that use SHADOZ data. Please email a reference of your manuscript to the archiver: Debra.E.Kollonige@nasa.gov

Publications using SHADOZ data should include the following:

1) Use the following DOIs:https://doi.org/10.57721/SHADOZ-V06 and https://doi.org/10.57721/SHADOZ-V01-UNC
2) Cite the following articles:
• Thompson, A. M., Stauffer, R. M., Wargan, K., Witte, J. C., Kollonige, D. E., & Ziemke, J. R., Regional and seasonal trends in tropical ozone from SHADOZ profiles: Reference for models and satellite products (2021), J. of Geophys. Res. Atmos., 126, https://doi.org/10.1029/2021JD034691.
• Witte, J.C., A. M. Thompson, H. G. J. Smit, M. Fujiwara, F. Posny, Gert J. R. Coetzee, ... F. R. da Silva (2017), First reprocessing of Southern Hemisphere ADditional OZonesondes (SHADOZ) profile records (1998-2015): 1. Methodology and evaluation, J. Geophys. Res. Atmos., 122, 6611-6636. https://doi.org/10.1002/2016JD026403.
• Thompson, A. M., J. C. Witte, C., Sterling, A., Jordan, B. J., Johnson, S. J. Oltmans, ... Thiongo, K. (2017). First reprocessing of Southern Hemisphere Additional Ozonesondes (SHADOZ) ozone profiles (1998-2016): 2. Comparisons with satellites and ground-based instruments. Journal of Geophysical Research: Atmospheres, 122, 13,000-13,025. https://doi.org/10.1002/2017JD027406..
• Witte, J. C., Thompson, A. M., Smit, H. G. J., Vömel, H., Posny, F., & Stübi, R. (2018). First reprocessing of Southern Hemisphere ADditional OZonesondes profile records: 3. Uncertainty in ozone profile and total column. Journal of Geophysical Research: Atmospheres, 123, 3243-3268. https://doi.org/10.1002/2017JD027791..
• Sterling, C. W., B. J. Johnson, S. J., Oltmans, H. G. J. Smit, A., Jordan, P. D., Cullis, E. G., Hall, A. M., Thompson, and J. C. Witte (2017). Homogenizing and Estimating the Uncertainty in NOAA's Long Term Vertical Ozone Profile Records Measured with the Electrochemical Concentration Cell Ozonesonde, Atmos. Meas. Tech. https://doi.org/10.5194/amt-2017-397.

Data Disclaimer and Guidelines:

The data on this website are subject to revision and reprocessing. Check dates of creation to download the most current version. Contact the co-investigators for questions concerning data techniques and quality.

Access to these data is free to the public. Whenever substantial use is made of their data, you accept that an offer of co-authorship will be made through personal contact. In all cases, an acknowledgement must be made to the data co-investigators and SHADOZ when these data are used in publication. Click here for a list of contact information on the SHADOZ station PI's

SHADOZ reserves the right to limit access to the Data Archive and to alter or change the layout and content of the website.