First Reprocessing of Southern Hemisphere ADditional OZonesondes (SHADOZ) Profile Records: 3. Uncertainty in Ozone Profile and Total Column

• Published in: Journal of geophysical research. Atmospheres Vol. 123; no. 6; p. 3243
• Main Authors: Witte, Jacquelyn C, Thompson, Anne M, Smit, Herman G J, Vömel, Holger, Posny, Françoise, Stübi, Rene
• Format: Journal Article
• Language: English
• Published: United States 27.03.2018
• Subjects: Ozonesonde; Ozone; SHADOZ; Tropics
• ISSN: 2169-897X
• DOI: 10.1002/2017JD027791

Reprocessed ozonesonde data from eight SHADOZ (Southern Hemisphere ADditional OZonesondes) sites have been used to derive the first analysis of uncertainty estimates for both profile and total column ozone (TCO). The ozone uncertainty is a composite of the uncertainties of the individual terms in the ozone partial pressure (P ) equation, those being the ozone sensor current, background current, internal pump temperature, pump efficiency factors, conversion efficiency, and flow-rate. Overall, P uncertainties (ΔP ) are within 15% and peak around the tropopause (15±3km) where ozone is a minimum and ΔP approaches the measured signal. The uncertainty in the background and sensor currents dominate the overall ΔP in the troposphere including the tropopause region, while the uncertainties in the conversion efficiency and flow-rate dominate in the stratosphere. Seasonally, ΔP is generally a maximum in the March-May, with the exception of SHADOZ sites in Asia, for which the highest ΔP occurs in September-February. As a first approach, we calculate sonde TCO uncertainty (ΔTCO) by integrating the profile ΔP and adding the ozone residual uncertainty, derived from the McPeters and Labow [2012] 1-σ ozone mixing ratios. Overall, ΔTCO are within ±15 DU, representing ~5-6% of the TCO. TOMS and OMI satellite overpasses are generally within the sonde ΔTCO. However, there is a discontinuity between TOMS v8.6 (1998-2004/09) and OMI (2004/10-2016) TCO on the order of 10DU that accounts for the significant 16DU overall difference observed between sonde and TOMS. By comparison, the sonde-OMI absolute difference for the eight stations is only ~4DU.