Insights into Tropical Ozone Profiles, Biases and Uncertainties Using 20 Years of SHADOZ Reprocessed Data

Ozone profiles measured from sondes have become indispensable references for satellite algorithms and trends analysis in the lower stratosphere, sometimes in combination with other datasets. However, the electrochemical concentration cell ozonesonde is subject to variations (e.g., chemical composition of the sensing solution, manufacturer, amount of solution in the cells, calibration procedures) that can introduce artifacts into the measurement. These appear as discontinuities in ozone time-series at an individual station or as biases among stations when their records are compared to independent ozone data from satellites or ground-based instruments (Dobson, Brewer, SAOZ). The 20-year (1998-2017) SHADOZ (Southern Hemisphere ADditional OZonesondes) record (https://tropo.gsfc.nasa.gov/shadoz) has been reprocessed recently to give data for 14 stations in the tropics and subtropics, including uncertainty estimates of each ozone profile. We present ozone profile and total column ozone (TCO) comparisons with co-located ground-based instruments and with information from satellite overpasses, e.g., Aura MLS and OMI, SNPP OMPS. The TCO agreements are all within 5% and biases among the stratospheric profile segments for ten tropical stations are reduced compared to our published 2012 and 2017 evaluations. Ozone readings for the most recently reprocessed data, from the Paramaribo, Suriname station (5.8N, 55.2W), are highlighted. Reprocessed TCO ozone shows improved agreement with the ground and satellite references and a markedly reduced bias in the lower stratospheric profile.