First Reprocessing of Southern Hemisphere Additional Ozonesondes (SHADOZ) Ozone Profiles (1998–2016): 2. Comparisons With Satellites and Ground‐Based Instruments

Abstract

The Southern Hemisphere ADditional OZonesonde (SHADOZ) network was assembled to validate a new generation of ozone‐monitoring satellites and to better characterize the vertical structure of tropical ozone in the troposphere and stratosphere. Beginning with nine stations in 1998, more than 7,000 ozone and P‐T‐U profiles are available from 14 SHADOZ sites that have operated continuously for at least a decade. We analyze ozone profiles from the recently reprocessed SHADOZ data set that is based on adjustments for inconsistencies caused by varying ozonesonde instruments and operating techniques. First, sonde‐derived total ozone column amounts are compared to the overpasses from the Earth Probe/Total Ozone Mapping Spectrometer, Ozone Monitoring Instrument, and Ozone Mapping and Profiler Suite satellites that cover 1998–2016. Second, characteristics of the stratospheric and tropospheric columns are examined along with ozone structure in the tropical tropopause layer (TTL). We find that (1) relative to our earlier evaluations of SHADOZ data, in 2003, 2007, and 2012, sonde‐satellite total ozone column offsets at 12 stations are 2% or less, a significant improvement; (2) as in prior studies, the 10 tropical SHADOZ stations, defined as within ±19° latitude, display statistically uniform stratospheric column ozone, 229 ± 3.9 DU (Dobson units), and a tropospheric zonal wave‐one pattern with a 14 DU mean amplitude; (3) the TTL ozone column, which is also zonally uniform, masks complex vertical structure, and this argues against using satellites for lower stratospheric ozone trends; and (4) reprocessing has led to more uniform stratospheric column amounts across sites and reduced bias in stratospheric profiles. As a consequence, the uncertainty in total column ozone now averages 5%.

Recent Decline in Extratropical Lower Stratospheric Ozone Attributed to Circulation Changes

“…Ozonesonde data do not always meet that criterion owing to changes in sensing solutions and sonde types (Hubert et al, 2016;Thompson et al, 2017;Witte et al, 2017). This limited selection is motivated by the need to use data records suitable for trend analyses and located in the regions of interest.…”

“…This limited selection is motivated by the need to use data records suitable for trend analyses and located in the regions of interest. Ozonesonde data do not always meet that criterion owing to changes in sensing solutions and sonde types (Hubert et al, 2016;Thompson et al, 2017;Witte et al, 2017). The data used here were recently reprocessed with the "SkySonde" algorithm to correct for these changes.…”

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

“…The Intercontinental Chemical Transport Experiment Ozonesonde Network Study (IONS) series of North American campaigns collected hundreds of soundings with daily launches from 8 to 20 sites over 3 to 6 week periods to augment aircraft in situ and lidar profiles (Thompson, Stone, et al, 2007;Thompson et al, 2008Thompson et al, , 2011. Studies using tropical ozonesonde measurements have examined the tropical wave-one feature (Sauvage et al, 2006;Thompson et al, 2003Thompson et al, , 2017, quasi-biennial oscillations and El Niño-Southern Oscillation features (Lee et al, 2010;Logan et al, 2003;Randel & Thompson, 2011;Thompson et al, 2001;Witte et al, 2008), and the tropical transition layer (Corti et al, 2006;Folkins et al, 1999;Fu et al, 2007;Gettelman & Forster, 2002;Randel et al, 2007;Thompson et al, 2012).…”

Characterizing Global Ozonesonde Profile Variability From Surface to the UT/LS With a Clustering Technique and MERRA‐2 Reanalysis

“…Refer to Table for a list of supporting institutions. Ozone profile data from Uccle and De Bilt, and the SHADOZ stations (except Samoa) have been reprocessed to reflect the latest guidelines for homogenization of historical ozonesonde data (Deshler et al, ; Smit and the Panel for the Assessment of Standard Operating Procedures for Ozonesondes, ; Smit and the Panel for the Assessment of Standard Operating Procedures for Ozonesondes, ; Thompson et al, ; Van Malderen et al, ; Witte et al, ). Reprocessed data from Uccle and De Bilt can be obtained directly from the station data managers (see Acknowledgments section).…”

“…Figure is a convenient way to visualize the dominant O 3 profile types and the variability in O 3 with latitude, and longitude in the case of the tropics. We observe the tropical wave‐one pattern (Thompson et al, ; Thompson, Witte, Oltmans, et al, ) in low‐tropospheric to midtropospheric O 3 from the tropical Pacific (low tropospheric O 3 amounts at Watukosek, Kuala Lumpur, and Samoa) to the tropical Atlantic (high tropospheric O 3 amounts at Natal and Ascension Island). The invariance of the tropopause altitude at low latitudes from clusters 1 to 4 is also evident.…”