Project dustorm report: ozone transport, in situ measurements, and meteorological analyses of tropopause folding

Danielsen, Edwin F.; Mohnen, Volker A.

doi:10.1029/jc082i037p05867

Cited by 264 publications

(130 citation statements)

References 5 publications

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“…3) Many clean air sites, remote from the effects of industrial activity, typically depict a winter ozone maximum and a summer minimum, for example Cape Grim in Tasmania (Logan, 1985;Elsworth et al, 1988). This pattern of seasonal change is consistent with the injection of stratospheric ozone-rich air into the troposphere, which is most effective in the late winter and spring months (Danielsen, 1968;Danielsen and Mohnen, 1977;Mahlman and Moxim, 1978) and has been cited by many authors as the source of tropospheric ozone at these locations (Oltmans, 1981;Logan, 1985;Scheel et al, 1990). It should be noted, however, that this is not the only process governing the seasonal cycle of surface ozone.…”

Section: Surface Ozone Characteristicsmentioning

confidence: 49%

Relationship between surface, free tropospheric and total column ozone in two contrasting areas in South Africa

Combrink¹,

Diab²,

Sokolic³

et al. 1995

Atmospheric Environment

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Abstract-Measurements of surface ozone in two contrasting areas of South Africa are compared with free tropospheric and Total Ozone Mapping Spectrometer (TOMS) total column ozone data. Cape Point is representative of a background monitoring station which is remote from pollution impacts, whereas the Eastern Transvaal Highveld (ETH) stations of Elandsfontein and Verkykkop are situated in an area of intense urban and industrial activity. At Cape Point the diurnal cycle in surface ozone is small, the seasonal cycle shows a winter maximum and a summer minimum. In contrast, the ETH stations show a spring maximum in surface ozone with evidence of a summer enhancement. Comparison with Cape Point data suggests that photochemical ozone production accounts for about 50% of the background value. Seasonal variations in total ozone are consistent over the whole of South Africa, indicating a cycle which is independent of varying surface ozone concentrations. The spring maximum in free tropospheric ozone (up to 12 km) over the interior of South Africa is thought to be due to long-range transport of biomass burn products from latitudes to the north, rather than the extension of a localised surface photochemical influence through the troposphere.

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Section: Surface Ozone Characteristicsmentioning

confidence: 49%

Relationship between surface, free tropospheric and total column ozone in two contrasting areas in South Africa

Combrink¹,

Diab²,

Sokolic³

et al. 1995

Atmospheric Environment

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“…(e.g., Danielsen and Mohnen, 1977;Oltmans, 1981;Levy et al, 1985;Logan, 1985Logan, , 1999Wang et al, 1998;Stohl et al, 2003) and active photochemical production (e.g., Liu et al, 1987;Wang et al, 1998;Yienger et al, 1999). Surface measurements of radioactive debris ( 90 Sr) and Beryllium-7 ( 7 Be) also show a spring maximum associated with the seasonal cycle of stratosphere-troposphere exchange (STE) (e.g.…”

Section: Introductionmentioning

confidence: 99%

The governing processes and timescales of stratosphere-to-troposphere transport and its contribution to ozone in the Arctic troposphere

et al. 2009

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Abstract. We used the seasonality of a combination of atmospheric trace gases and idealized tracers to examine stratosphere-to-troposphere transport and its influence on tropospheric composition in the Arctic. Maximum stratosphere-to-troposphere transport of CFCs and O 3 occurs in April as driven by the Brewer-Dobson circulation. Stratosphere-troposphere exchange (STE) occurs predominantly between 40 • N to 80 • N with stratospheric influx in the mid-latitudes (30-70 • N) accounting for 67-81% of the air of stratospheric origin in the Northern Hemisphere extratropical troposphere. Transport from the lower stratosphere to the lower troposphere (LT) takes three months on average, one month to cross the tropopause, the second month to travel from the upper troposphere (UT) to the middle troposphere (MT), and the third month to reach the LT. During downward transport, the seasonality of a trace gas can be greatly impacted by wet removal and chemistry. A comparison of idealized tracers with varying lifetimes suggests that when initialized with the same concentrations and seasonal cycles at the tropopause, trace gases that have shorter lifetimes display lower concentrations, smaller amplitudes, and earlier seasonal maxima during transport to the LT. STE contributes to O 3 in the Arctic troposphere directly from the transport of O 3 and indirectly from the transport of NO y . Direct transport of O 3 from the stratosphere accounts for 78% of O 3 in the Arctic UT with maximum contributions occurring from March to May. The stratospheric contribuCorrespondence to: Q. Liang (Qing.Liang@nasa.gov) tion decreases significantly in the MT/LT (20-25% of total O 3 ) and shows a very weak March-April maximum. Our NO x budget analysis in the Arctic UT shows that during spring and summer, the stratospheric injection of NO y -rich air increases NO x concentrations above the 20 pptv threshold level, thereby shifting the Arctic UT from a regime of net photochemical ozone loss to one of net production with rates as high as +16 ppbv/month.

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“…There have been numerous attempts to estimate STT from experimental data (e.g., Danielsen and Mohnen, 1977;Viezee et al, 1983;Beekmann, et al, 1997; more information may be obtained from the references in these papers and in the general overview papers by Holton et al, 1996 andStohl et al, 2003). Results from case studies or a large number of vertical profile measurements have been used and extrapolated to the Northern Hemisphere or the entire globe by using assumptions such as model-derived geographical distributions of the tropopause folding activity.…”

Section: Introductionmentioning

confidence: 99%

Forecasted deep stratospheric intrusions over Central Europe: case studies and climatologies

et al. 2010

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Abstract. Based on daily predictions of stratospheric air intrusions, obtained from trajectory calculations by ETH Zürich with wind fields from ECMWF forecasts, a high number of measurements with the ozone lidar at IMK-IFU (Garmisch-Partenkirchen, Germany) were carried out in 2001. The lidar measurements show a large variety of rather different cases reflecting the full complexity of intrusion episodes that is not visible in classical case studies. In part, tropopause folds could be fully captured. The frequency of intrusion cases forecasted and verified by vertical sounding or in the in-situ data recorded at the nearby Zugspitze summit (2962 m a.s.l.) exceed that in previous work by more than a factor of two. Three cases mapped with the lidar were selected to validate the results for the corresponding time periods extracted from a one-year run with the new hemispheric version of the chemistry-transport model EURAD. Due to the high spatial resolution chosen for these simulations the agreement with the lidar measurements is satisfactory. The Zugspitze ozone data from 1978 to 2004 were recently filtered by applying different criteria for stratospheric air, based on the 7 Be and humidity measurements. Here, by using the daily model forecasts during the time period 2001-2005, we examine three criteria and determine how well they represent the stratospheric air intrusions reaching the mountain site. Seasonal cycles for the period 2001-2005 were derived forCorrespondence to: T. Trickl (thomas.trickl@kit.edu) the forecasts as well as the intrusion frequency per month for the forecasted intrusions and each of the criteria, distinguishing eight different characteristic transport pathways. In most cases a winter maximum and a summer minimum was obtained, but in the case of cyclonic arrival of intrusions starting over Greenland a late-spring maximum is seen. Two of the filtering criteria examined, based on combining a relativehumidity (RH) threshold of 60% with either a 7 Be threshold of 5.5 mBq m −3 or the requirement for RH≤30% within ±6 h, rather reliably predict periods of deep intrusions reaching the Zugspitze station. An "or" combination of both these criteria yields slightly more cases and covers 77.9% of the intrusions identified. The lack of observations in the complementary 22.1% are mostly explained by overpasses. In this way the long-term trend of stratospheric ozone observed at this site as well as the corresponding ozone budget may be derived on the basis of measurements only. This effort will be the subject of a subsequent publication.

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Project dustorm report: ozone transport, in situ measurements, and meteorological analyses of tropopause folding

Cited by 264 publications

References 5 publications

Relationship between surface, free tropospheric and total column ozone in two contrasting areas in South Africa

Relationship between surface, free tropospheric and total column ozone in two contrasting areas in South Africa

The governing processes and timescales of stratosphere-to-troposphere transport and its contribution to ozone in the Arctic troposphere

Forecasted deep stratospheric intrusions over Central Europe: case studies and climatologies

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