Subtropical tropopause break as a possible stratospheric source of ozone in the tropical troposphere

Baray, Jean-Luc; Ancellet, Gérard; Taupin, F. G.; Bessafi, Miloud; Baldy, S.; Keckhut, Philippe

doi:10.1016/s1364-6826(97)00116-8

Cited by 68 publications

(58 citation statements)

References 25 publications

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“…2a Ozone increases due to stratospheric intrusions have been detected in South Africa and over the Indian Ocean. These intrusions take place in association with meteorological disturbances such as tropopause folds induced by the subtropical jet stream, cut off lows, tropical cyclones (Baray et al, 1998, westerly waves and frontal zones. According to James et al's climatology (2003) stratospheric intrusions in the southern subtropical region maximise during austral winter.…”

Section: Lidarmentioning

confidence: 99%

“…-The influence of stratosphere-troposphere exchange induced by the subtropical jet stream is at a maximum in JJA, because of the location of the jet stream close to the latitude of Reunion (Baray et al, 1998;Randriambelo et al, 2000).…”

Section: Ozone Trendsmentioning

confidence: 99%

“…For this region, the dynamical mechanisms influencing tropospheric ozone distribution have been documented, including intrusions of stratospheric air masses via tropopause folds (Baray et al, 1998), Rossby wave breaking (Postel and Hitchman, 1999) and mid latitude cut off lows . A study of the effect of tropical convection on tropospheric ozone has also been reported (Leclair de Bellevue et al,2006) and showed some differences between the two sites, Reunion and Irene.…”

Section: Introductionmentioning

confidence: 99%

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Tropospheric ozone climatology at two Southern Hemisphere tropical/subtropical sites, (Reunion Island and Irene, South Africa) from ozonesondes, LIDAR, and in situ aircraft measurements

et al. 2009

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Abstract. This paper presents a climatology and trends of tropospheric ozone in the Southwestern Indian Ocean (Reunion Island) and South Africa (Irene and Johannesburg). This study is based on a multi-instrumental dataset: PTU-O 3 ozonesondes, DIAL LIDAR and MOZAIC airborne instrumentation.The seasonal profiles of tropospheric ozone at Reunion Island have been calculated from two different data sets: ozonesondes and LIDAR. The two climatological profiles are similar, except in austral summer when the LIDAR profiles show greater values in the free troposphere, and in the upper troposphere when the LIDAR profiles show lower values during all seasons. These results show that the climatological value of LIDAR profiles must be discussed with care since LIDAR measurements can be performed only under clear sky conditions, and the upper limit of the profile depends on the signal strength.In addition, linear trends have been calculated from ozonesonde data at Reunion and Irene. Considering the whole tropospheric column, the trend is slightly positive for Reunion, and more clearly positive for Irene. Trend calculations have also been made separating the troposphere into Correspondence to: G. Clain (gaelle.clain@univ-reunion.fr) three layers, and separating the dataset into seasons. Results show that the positive trend for Irene is governed by the lower layer that is affected by industrial pollution and biomass burning. On the contrary, for Reunion Island, the strongest trends are observed in the upper troposphere, and in winter when stratosphere-troposphere exchange is more frequently expected.

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Section: Lidarmentioning

confidence: 99%

Section: Ozone Trendsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Tropospheric ozone climatology at two Southern Hemisphere tropical/subtropical sites, (Reunion Island and Irene, South Africa) from ozonesondes, LIDAR, and in situ aircraft measurements

et al. 2009

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“…Austin (1991) and Follows (1992) reported that stratospheric intrusions are due to tropopause folding or the strong vertical wind shear. Baray et al (1998Baray et al ( , 2000 discussed the ozone enhancement in the upper troposphere. These studies suggest that subtropical jet stream could be the origin of tropopause folding, leading to stratospheric intrusion to the troposphere.…”

Section: Introductionmentioning

confidence: 99%

Seasonal stratospheric intrusion of ozone in the upper troposphere over India

Chakraborty

Beig

2010

Ann. Geophys.

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“…The PV intrusions can influence the distribution of minor constituents. Folkins and Appenzeller (1996) and Baray et al (1998) observed sudden changes in ozone mixing ratio at tropical latitudes in connection with the PV intrusion. Ryoo et al (2008) studied the variability of subtropical UTRH during the northern winter and reported that both convection and poleward advection during PV intrusions could contribute towards increase in UTRH.…”

Section: Introductionmentioning

confidence: 97%

Tropical upper tropospheric humidity variations due to potential vorticity intrusions

2015

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Abstract. Four cases (March 2009, May 2009, April 2010 and February 2012 are presented in which the ERA-interim relative humidity (RH) shows consistent increase by more than 50 % in the upper troposphere (200-250 hPa) over tropics at the eastward side of the potential vorticity (PV) intrusion region. The increase in RH is confirmed with the spaceborne microwave limb sounder observations and radiosonde observations over Gadanki (13.5 • N, 79.2 • E) and is observed irrespective of whether the PV intrusions are accompanied by deep convection or not. It is demonstrated that the increase in RH is due to poleward advection induced by the PV intrusions in their eastward side at the upper tropospheric heights. It is suggested that the low-latitude convection, which is not necessarily triggered by the PV intrusion, might have transported water vapour to the upper tropospheric heights.

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Subtropical tropopause break as a possible stratospheric source of ozone in the tropical troposphere

Cited by 68 publications

References 25 publications

Tropospheric ozone climatology at two Southern Hemisphere tropical/subtropical sites, (Reunion Island and Irene, South Africa) from ozonesondes, LIDAR, and in situ aircraft measurements

Tropospheric ozone climatology at two Southern Hemisphere tropical/subtropical sites, (Reunion Island and Irene, South Africa) from ozonesondes, LIDAR, and in situ aircraft measurements

Seasonal stratospheric intrusion of ozone in the upper troposphere over India

Tropical upper tropospheric humidity variations due to potential vorticity intrusions

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