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

ABSTRACT: 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 (PO3) equation, those being the ozone sensor current, background current, internal pump temperature, pump efficiency factors, conversion efficiency, and flow-rate. Overall, PO3 uncertainties (?PO3) are within 15% and peak around the tropopause (15±3km) where ozone is a minimum and ?PO3 approaches the measured signal. The uncertainty in the background and sensor currents dominate the overall ?PO3 in the troposphere including the tropopause region, while the uncertainties in the conversion efficiency and flow-rate dominate in the stratosphere. Seasonally, ?PO3 is generally a maximum in the March-May, with the exception of SHADOZ sites in Asia, for which the highest ?PO3 occurs in September-February. As a first approach, we calculate sonde TCO uncertainty (?TCO) by integrating the profile ?PO3 and adding the ozone residual uncertainty, derived from the McPeters and Labow [2012] 1-? ozone mixing ratios. Overall, ?TCO are within ±15 DU, representing ~5-6% of the TCO. TOMS and OMI satellite overpasses are generally within the sonde ?TCO. 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.

SUBMITTER: Witte JC 

PROVIDER: S-EPMC7641110 | biostudies-literature | 2018 Mar

REPOSITORIES: biostudies-literature