Trends of ozone in the troposphere

Oltmans, S. J.; Lefohn, Allen S.; Scheel, H. E.; Harris, Joyce M.; Levy, H.; Galbally, Ian E.; Brunke, E.-G.; Meyer, C. P.; Lathrop, J. A.; Johnson, B. J.; Shadwick, Douglas S.; Cuevas, E.; Schmidlin, F. J.; Tarasick, D. W.; Claude, H.; Kerr, J. B.; Uchino, Osamu; Mohnen, Volker A.

doi:10.1029/97gl03505

Cited by 169 publications

(123 citation statements)

References 7 publications

(5 reference statements)

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“…There are many problems associated with these early measurements, and pre-industrial ozone levels may have been closer to 20 ppbv as measured at Arosa in the 1950s (Staehelin et al, 1994). Studies of ozone-sonde data in the free troposphere (Logan, 1994;Logan et al, 1999;Oltmans et al, 1998) point to a general increase in free tropospheric ozone up to the mid 1980s, and then a mixed picture with many sites/regions showing no significant trend, or even negative trends, after that. In WMO (2002) trends have been calculated including 4 more years (1996)(1997)(1998)(1999)(2000), but these additional 4 years did not alter the conclusions significantly.…”

Section: Measured Global/hemispheric Trendsmentioning

confidence: 99%

Can we explain the trends in European ozone levels?

et al. 2006

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Abstract. Ozone levels in Europe are changing. Emissions of ozone precursors from Europe (NO x , CO and nonmethane hydrocarbons) have been substantially reduced over the last 10-15 years, but changes in ozone levels cannot be explained by changes in European emissions alone. The observed ozone trends at many European sites are only partially reproduced by global or regional photochemistry models, and possible reasons for this are discussed.In order to further explain the European trends in ozone since 1990, the EMEP regional photochemistry model has been run for the years 1990 and 1995-2002. The EMEP model is a regional model centred over Europe but the model domain also includes most of the North Atlantic and the polar region. Climatological ozone data are used as initial and lateral boundary concentrations. Model results are compared to measurements over this timespan of 12 years. Possible causes for the measured trends in European surface ozone have been investigated using model sensitivity runs perturbing emissions and lateral boundary concentrations. The increase in winter ozone partially, and the decrease in the magnitude of high ozone episodes, is attributed to the decrease in ozone precursor emissions since 1990 by the model. Furthermore, the model calculations indicate that the emission reductions have resulted in a marked decrease in summer ozone in major parts of Europe, in particular in Germany. Such a trend in summer ozone is likely to be difficult to identify from the measurements alone because of large inter-annual variability.

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Section: Measured Global/hemispheric Trendsmentioning

confidence: 99%

Can we explain the trends in European ozone levels?

et al. 2006

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“…Jacob et al [1999] projected that industrialization of eastern Asia would increase mean surface O3 concentrations over the United States by 2-6 ppbv over the 1985-2010 period, significantly offsetting the benefits of domestic emission controls. Observations at Whiteface Mountain (1480 m) in New York State indicate an increase of 4±2 ppbv over the period 1974-1995[Oltmans et al, 1998. Ozonesonde data in the free troposphere at Wallops Island (Virginia) and Boulder (Colorado) show no significant increase over the past two decades but the data are sparse [Oltmans et al, 1998;Logan et al, 1999].…”

Section: Introductionmentioning

confidence: 99%

“…Observations at Whiteface Mountain (1480 m) in New York State indicate an increase of 4±2 ppbv over the period 1974-1995[Oltmans et al, 1998. Ozonesonde data in the free troposphere at Wallops Island (Virginia) and Boulder (Colorado) show no significant increase over the past two decades but the data are sparse [Oltmans et al, 1998;Logan et al, 1999].…”

Section: Introductionmentioning

confidence: 99%

Increasing background ozone in surface air over the United States

Lin

Jacob

Munger

et al. 2000

Geophysical Research Letters

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The long‐term trend of background O3 in surface air over the United States from 1980 to 1998 is examined using monthly probability distributions of daily maximum 8‐hour average O3 concentrations at a large ensemble of rural sites. Ozone concentrations have decreased at the high end of the probability distribution (reflecting emission controls) but have increased at the low end. The cross‐over takes place between the 30th and 50th percentiles in May–August and between the 60th and 90th percentiles during the rest of the year. The increase is statistically significant at a 5% level in spring and fall, when it is 3–5 ppbv. The maximum increase is in the Northeast. A possible explanation is an increase in the O3 background transported from outside the United States. Better understanding of the causes of the increase is needed because of its implications for meeting O3 air quality standards.

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“…A comparison of slopes of the regression lines enables to infer temporal variations of the long-term trend in last decades. Recently a concept of trend evaluation using a smooth curve fit to the ozone data has been evolving (Harris et al, 2003;Krzyścin et al, 2005;Oltmans et al, 2006;and Krzyścin, 2006). The trend means continuing and smooth change over a given time period.…”

Section: Trend Modelmentioning

confidence: 99%

Variability of the total ozone trend over Europe for the period 1950–2004 derived from reconstructed data

Krzyścin

Borkowski

2008

Atmos. Chem. Phys.

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Abstract. The total ozone data over Europe are available for only few ground-based stations in the pre-satellite era disallowing examination of the spatial trend variability over the whole continent. A need of having gridded ozone data for a trend analysis and input to radiative transfer models stimulated a reconstruction of the daily ozone values since January 1950. Description of the reconstruction model and its validation were a subject of our previous paper. The data base used was built within the objectives of the COST action 726 "Long-term changes and climatology of UV radiation over Europe". Here we focus on trend analyses. The long-term variability of total ozone is discussed using results of a flexible trend model applied to the reconstructed total ozone data for the period 1950-2004. The trend pattern, which comprises both anthropogenic and "natural" component, is not a priori assumed but it comes from a smooth curve fit to the zonal monthly means and monthly grid values. The ozone long-term changes are calculated separately for cold (October-next year April) and warm (May-September) seasons. The confidence intervals for the estimated ozone changes are derived by the block bootstrapping. The statistically significant negative trends are found almost over the whole Europe only in the period 1985-1994. Negative trends up to −3% per decade appeared over small areas in earlier periods when the anthropogenic forcing on the ozone layer was weak . The statistically positive trends are found only during warm seasons 1995-2004 over Svalbard archipelago. The reduction of ozone level in 2004 relative to that before the satellite era is not dramatic, i.e., up to ∼−5% and ∼−3.5% in the cold and warm subperiod, respectively. Present ozone level is still depleted over many popular resorts in southern Europe and northern Africa. For high latitude regions the trend overturning could be inferred in last decade

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Trends of ozone in the troposphere

Cited by 169 publications

References 7 publications

Can we explain the trends in European ozone levels?

Can we explain the trends in European ozone levels?

Increasing background ozone in surface air over the United States

Variability of the total ozone trend over Europe for the period 1950–2004 derived from reconstructed data

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