A tropical Atlantic Paradox: Shipboard and satellite views of a tropospheric ozone maximum and wave‐one in January–February 1999

Thompson, Anne M.; Doddridge, Bruce G.; Witte, J. C.; Hudson, R. D.; Luke, Winston T.; Johnson, James E.; Johnson, B. J.; Oltmans, S. J.; Weller, Rolf

doi:10.1029/1999gl011273

Cited by 127 publications

(204 citation statements)

References 11 publications

Supporting

Mentioning

190

Contrasting

Order By: Relevance

“…1b and 2f), with ozone precursors probably being injected into the continental south-easterlies as they pass over the fires of the Democratic Republic of Congo, Zambia and Zimbabwe before moving up to Brazzaville and Luanda. This connection is robust with both the 3-D streamlines and the individual back-trajectories with more than 86% and 81% respectively, calculated over 2000). It confirms findings by Garstang et al (1996) during the TRACE-A campaign about the anticyclonic circulation over the subcontinent during the winter half-year that reaches a 80% daily occurrence in July, allowing a circulation from the east on the northern edge of the high.…”

Section: Central and East Africamentioning

confidence: 96%

“…These field missions focused mainly on emissions from tropical ecosystems and on the photochemistry of lower and middle troposphere. The first results came from DECAFE (1988 -Congo), FOS/DECAFE (1991 Ivory Coast) followed by EXPRESSO (1996 Central Africa); and SAFARI/TRACE-A (1992-2000. They provided evidence of biomass burning emissions over Africa.…”

Section: Introductionmentioning

confidence: 99%

“…They provided evidence of biomass burning emissions over Africa. 21-09-1992 to 26-10-1992 Chemistry near the Equator-Atlantic" [1987, 1988Smit et al,] 1989;Weller et al, 1996] Aerosols99 cruise [Thompson et al, 2000] January February 1999 Northern Hemisphere Dry season (New York City Cape Town) SHADOZ [Thompson et al, 2002] from 1998 on. once a week "Southern Hemisphere Nairobi (over Africa) ADditional Ozonesondes" EXPRESSO [Cautenet et al, 1999] November 1996 to December 1996 Part of DECAFE programme Central Africa…”

Section: Introductionmentioning

confidence: 99%

“…Indeed the TOMS Tropical Tropospheric Ozone Content (TTOC) do not capture the seasonal maximum due to biomass burning found in observations and models over sub-Saharan northern Africa (Thompson et al, 2002;Martin et al, 2002). This insensitivity in the lower troposphere increases the "tropical Atlantic paradox" (Thompson et al, 2000), i.e. the north-south gradient reversal in ozone over the tropical Atlantic during the northern African biomass burning season in December-February (DJF).…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Tropospheric ozone over Equatorial Africa: regional aspects from the MOZAIC data

et al. 2005

View full text Add to dashboard Cite

Abstract. We analyze ozone observations recorded over Equatorial Africa between April 1997 and March 2003 by the MOZAIC programme, providing the first ozone climatology deriving from continental in-situ data over this region. Threedimensional streamlines strongly suggests connections between the characteristics of the ozone monthly mean vertical profiles, the most persistent circulation patterns in the troposphere over Equatorial Africa (on a monthly basis) such as the Harmattan, the African Easterly Jet, the Trades and the regions of ozone precursors emissions by biomass burning. During the biomass burning season in each hemisphere, the lower troposphere exhibits layers of enhanced ozone (i.e. 70 ppbv over the coast of Gulf of Guinea in December-February and 85 ppbv over Congo in June-August). The characteristics of the ozone monthly mean vertical profiles are clearly connected to the regional flow regime determined by seasonal dynamic forcing. The mean ozone profile over the coast of Gulf of Guinea in the burning season is characterized by systematically high ozone below 650 hPa ; these are due to the transport by the Harmattan and the AEJ of the pollutants originating from upwind fires. The confinement of high ozone to the lower troposphere is due to the high stability of the Harmattan and the blocking Saharan anticyclone which prevents efficient vertical mixing. In contrast, ozone enhancements observed over Central Africa during the local dry season (June-August) are not only found in the lower troposphere but throughout the troposphere. Moreover, this study highlights a connection between the regions of the coast of Gulf of Guinea and regions of Congo to the south that appears on a semi annual basis. Vertical profiles in wet-season regions exhibit ozone enhancements in the lower troposphere due to biomass burning products transport from fires situated in the opposite dry-season hemisphere.

show abstract

Section: Central and East Africamentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Tropospheric ozone over Equatorial Africa: regional aspects from the MOZAIC data

et al. 2005

View full text Add to dashboard Cite

show abstract

“…Earlier shipboard observations of the vertical distribution of ozone were mostly conducted crossing the Atlantic (Herman et al 1989;Weller et al 1996;Thompson et al 2000). One equatorial mission in the western and central equatorial Pacific was reported by Kley et al (1997).…”

Section: Introductionmentioning

confidence: 99%

Ozonesonde Observations in the Equatorial Eastern Pacific. The Shoyo-Maru Survey.

Shiotani

Fujiwara

Hasebe

et al. 2002

Journal of the Meteorological Society of Japan

View full text Add to dashboard Cite

We have conducted GPS radiosonde and ozonesonde observations on board the research vessel ''Shoyo-Maru'' in the equatorial eastern Pacific. These observations took place in September and October 1999 as a part of the Soundings of Ozone and Water in the Equatorial Region (SOWER)/Pacific mission. The mean profile of ozone is similar to that for the dry season (September to October) at San Cristóbal, Galá pagos (0.9 S, 89.6 W) located in the equatorial eastern Pacific. The mean tropospheric ozone concentration is about 40 ppbv with a maximum in the mid-troposphere. Compared with the mean profile during the dry season at Watukosek, Indonesia (7.5 S, 112.6 E), this mid-tropospheric maximum is larger, and a sharp increase of ozone below the tropopause begins at a lower altitude for the Shoyo-Maru profile. We frequently observed layers in which ozone and humidity are highly anti-correlated. These layers have vertical scales from several kilometers to several hundred meters. Horizontal scales of these layers are roughly 1000 km, which may correspond to time scales of about 2 days, since the vessel sailed about 500 km/day. These layers are related to northerly winds, which bring in wet and ozone-poor air from the inter-tropical convergence zone situated in the northern side of the main cruise track. Similar layers were observed in ozone profiles at San Cristóbal and Watukosek, mostly during the dry season, suggesting the existence of layers advected without vertical mixing.

show abstract

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

et al. 2017

Self Cite

View full text Add to dashboard Cite

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%.

show abstract

A tropical Atlantic Paradox: Shipboard and satellite views of a tropospheric ozone maximum and wave‐one in January–February 1999

Cited by 127 publications

References 11 publications

Tropospheric ozone over Equatorial Africa: regional aspects from the MOZAIC data

Tropospheric ozone over Equatorial Africa: regional aspects from the MOZAIC data

Ozonesonde Observations in the Equatorial Eastern Pacific. The Shoyo-Maru Survey.

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

Contact Info

Product

Resources

About