An estimate of the stratospheric contribution to springtime tropospheric ozone maxima using TOPSE measurements and beryllium‐7 simulations

Abstract

[1] Measurements of tropospheric ozone (O 3 ) between 30°N and 70°N show springtime maxima at remote locations. The contribution of seasonal changes in stratospheretroposphere exchange (STE) to these maxima was investigated using measurements from the Tropospheric Ozone Production about the Spring Equinox Experiment (TOPSE) campaign and the beryllium-7 ( 7 Be) distribution from a calculation driven by fields from the Goddard Earth Observing System Data Assimilation System (GEOS DAS).Comparison with TOPSE measurements revealed that upper tropospheric modelcalculated 7 Be mixing ratios were reasonable (a change from previous calculations) but that lower tropospheric mixing ratios were too low most likely due to an overestimation of scavenging. Temporal fluctuations were well captured although their amplitudes were often underestimated. Analysis of O 3 measurements indicated that O 3 mixing ratios increased by 5-10% month À1 for q < 300 K (the underworld) and by 10-15% month À1for q > 300 K (the tropospheric middleworld). 7 Be mixing ratios decreased with time for q < 290 K and increased with time for q > 300 K. Model-calculated middleworld increases of 7 Be were a factor of 2 less than measured increases.7 Be with a stratospheric source (strat-7 Be) increased by 4.6-8.8% month À1 along TOPSE flight paths within the tropospheric middleworld. Increases in strat-7 Be were not seen along TOPSE flight paths in the underworld. Assuming changes in tropospheric O 3 with a stratospheric source are the same as changes in strat-7 Be and that 50% of O 3 in the region of interest is produced in the stratosphere, changes in STE explain 20-60% of O 3 increases in the tropospheric middleworld and less than 33% of O 3 increases in the underworld.INDEX TERMS: 0368 Atmospheric Composition and Structure: Troposphere-constituent transport and chemistry; 3362 Meteorology and Atmospheric Dynamics: Stratosphere/troposphere interactions; 3337 Meteorology and Atmospheric Dynamics: Numerical modeling and data assimilation Citation: Allen, D. J., J. E. Dibb, B. Ridley, K. E. Pickering, and R. W. Talbot, An estimate of the stratospheric contribution to springtime tropospheric ozone maxima using TOPSE measurements and beryllium-7 simulations,

Multi-model study of mercury dispersion in the atmosphere: vertical and interhemispheric distribution of mercury species

“…This feature was observed on all three flights during spring and thus seems not to be an individual outlier. Furthermore, in the time from April to July stratospheric mass transport into the upper and mid-troposphere is known to occur regularly (Appenzeller and Holten, 1996;Allen et al, 2003;Zanis et al, 2003;Olsen et al, 2004;Schoeberl, 2004). Moreover, Sprenger et al (2003) and Sprenger and Wernli (2003) demonstrated that cross-tropopause mass flux is highest in the midlatitudes where these mercury profiles were measured.…”

Transport analysis of ozone enhancement in Southern Ontario during BAQS-Met

“…However, the overall importance of stratospheric ozone intrusions to the tropospheric ozone budget depends on their distribution with geography and season, and on the fate of the exchanged air parcels, particularly their vertical penetration and residence time Cooper et al, 2004;Thompson et al 2007;Tarasick and Slater, 2008). For these reasons, at least in part, observational estimates of the stratospheric contribution vary widely (e.g., Bachmeier et al, 1994;Browell et al, 1994Browell et al, , 2003Mauzerall et al, 1996;Dibb et al, , 1997Dibb et al, , 2003Allen et al, 2003;Bazhanov and Rodhe, 1997;Elbern et al, 1997;Li et al, 2002;Cooper et al, 2006;Thompson et al 2007).…”

Sensitivity of tropical tropospheric composition to lightning NOx production as determined by replay simulations with GEOS‐5

“…Budget analyses performed by Zhang et al [2003] showed that lightning contributes more than 50% of the upper tropospheric NO x over the United States from April to November, impacting the upper tropospheric O 3 budget by as much as 30%. Combined measurement and modeling studies performed by Cooper et al [2006Cooper et al [ , 2007 [Jacob, 1999;Martin et al, 2000], and (c) isentropic cross-tropopause transport of O 3 from the stratosphere [Allen et al, 2003;Jing et al, 2005].…”