Sulfate and nitrate mixing ratios in the vicinity of the tropopause

Lezberg, E. A.; Humenik, F. M.; Otterson, D. A.

doi:10.1016/0004-6981(79)90085-4

Cited by 8 publications

(3 citation statements)

References 11 publications

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“…Thus it appears that our high-sulfate concentrations at these altitudes (compared with observations) could be explained partly by (1) the decoupling of wet scavenging and convective mass transport and (2) partly by the explosive volcanic source. Taking into account the new assumptions, the midlatitude sulfates concentrations would reach 120 pptv in the higher troposphere, which is at the upper limit of observations by Lezberg et al [1979] ., 1986]). The measured velocities are however highly variable, depending on location, meteorological conditions, and time of the day.…”

Section: Referencesmentioning

confidence: 86%

A three‐dimensional study of the tropospheric sulfur cycle

Pham¹,

Müller²,

Brasseur³

et al. 1995

J. Geophys. Res.

260

167

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The global tropospheric distributions of seven important sulfur species were simulated with a global three‐dimensional chemistry‐transport model (IMAGES). Surface emission and deposition velocity maps were established for use as lower boundary conditions in the model. While anthropogenic SO2 emissions are by far the largest sulfur source in the northern midlatitudes, reduced sulfur compounds, notably dimethyl sulfide (DMS) predominate over most remote areas. Simulations were performed for the present‐day (∼ 1985) atmosphere. The calculated distributions are compared with available observations. The model results are found to be generally within a factor of (at most) 2–3 of long‐term observations. Comparison with campaign measurements is more difficult, mostly due to the strong dependence of sulfur species concentrations on local meteorological conditions. The results, however, indicate the need for future model refinements, especially with respect to biogenic emission estimates and parameterization of cloud processes. A sensitivity study is presented to discuss the uncertainties of the results related to several parameters (the decoupling of wet scavenging and convective transport for soluble species, volcanoes emission and deposition velocities). Results are also discussed in terms of global budgets and related variables and processes. Around 125 Tg S/yr of non‐sea‐salt (nss) sulfur compounds (DMS, CS2, H2S, COS, and SO2) are injected into the atmosphere. The balance is mainly maintained by nss‐sulfates wet and dry deposition, and by SO2 dry deposition (94% of total sulfur deposition). It is found that DMS oxidation represents the main contribution to SO2 chemical production (80% of the chemical sources), and that the major sink of SO2 is provided by in‐cloud oxidation (90% of the chemical sinks), under the assumption that all SO2 incorporated into clouds is oxidized. The calculated annual wet deposition of sulfates reaches 3 g S m−2 yr−1 over Europe and North America, while it is usually lower than 0.5 g S m−2 yr−1 in remote parts of the world. Estimations for the global lifetimes are 0.9 day for DMS, 4 days for CS2, 2.2 days for H2S, 0.6 day for SO2, 0.18 day for DMSO, 6.1 days for MSA, and 4.7 days for nss‐sulfates.

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Section: Referencesmentioning

confidence: 86%

A three‐dimensional study of the tropospheric sulfur cycle

Pham¹,

Müller²,

Brasseur³

et al. 1995

J. Geophys. Res.

260

167

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“…It began on June 4, 17 days after the first major eruption and continued intermittently until December 23. The instrumentation and techniques were available from an earlier sampling program of the upper troposphere and lower stratosphere [Lezberg et al, 1979;Humenik et al, 1980]. In this paper we present the results of chemical analysis of the filters for sulfate, nitrate, and chloride ions and X ray fluorescence analysis of the ash content in these filters for elements with atomic numbers >-25.…”

Section: Introductionmentioning

confidence: 99%

“…The filters included standard IPC-1478 filter material impregnated with dibutoxyethylphthalate (DBEP) and special IPC-1478 filter material impregnated with about 0.1% Na2CO3 solution and glycerine (about 2 mg Na2CO3 and 0.2 ml glycerine per filter). Details of the sampling procedures and subsequent preparation and analysis of the filters by ion chromatography are described by Lezberg et al [1979] and Hurnenik et al [1980]. Filter samples were initially analyzed for radioactive 7Be concentration by using a Ge(Li) detector and a multichannel pulse height analyser.…”

Section: Introductionmentioning

confidence: 99%

Aircraft sampling of the sulfate layer near the tropopause following the eruption of Mount St. Helens

Lezberg¹,

Otterson²,

Roberts³

et al. 1982

J. Geophys. Res.

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Twenty‐three filter sampling flights of the NASA Lewis F‐106 aircraft, were conducted in the Great Lakes region between June 4 and December 23, 1980, following the major eruption of Mount St. Helens (Washington State) on May 18. The IPC‐1478 filters were exposed over an altitude range spanning the local tropopause. A filter sample exposed above the tropopause on June 5 indicated a sulfate level of 50 times the baseline measurements, which is consistent with the trajectory predictions of the leading edge of the cloud on its second transit around the earth. Subsequent measurements over a period of 7 months revealed the existence of a layer of sulfate above the tropopause that decayed to a level of about 4 times previously measured background levels by the beginning of August. Concentration of nitrate above the tropopause exhibited considerable variability and showed some enhancement compared with previously measured concentration levels. On the basis of the null results of X ray fluorescence measurements, there is no evidence of ash particle concentrations >3.4 μm/m3 persisting in the layer above the tropopause following the second transit of the cloud.

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A global three-dimensional model of the tropospheric sulfur cycle

1991

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The tropospheric part of the atmospheric sulfur cycle has been simulated in a global threedimensional model. The model treats the emission, transport, chemistry, and removal processes for three sulfur components; DMS (dimethyl sulfide), SO, and SO% (sulfate). These processes are resolved using an Eulerian transport model, the MOGUNTIA model, with a horizontal resolution of 10 longitude by 10" latitude and with 10 layers in the vertical between the surface and 100 hPa. Advection takes place by climatological monthly mean winds. Transport processes occurring on smaller space and time scales are parameterized as eddy diffusion except for transport in deep convective clouds which is treated separately. The simulations are broadly consistent with observations of concentrations in air and precipitation in and over polluted regions in Europe and North America. Oxidation of DMS by OH radicals together with a global emission of 16 Tg DMS-S yr-' from the oceans result in DMS concentrations consistent with observations in the marine boundary layer. The average turn-over times were estimated to be 3, 1.2-1.8, and 3.2-6.1 days for DMS, SO,, and SOi-respectively.

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Sulfate and nitrate mixing ratios in the vicinity of the tropopause

Cited by 8 publications

References 11 publications

A three‐dimensional study of the tropospheric sulfur cycle

A three‐dimensional study of the tropospheric sulfur cycle

Aircraft sampling of the sulfate layer near the tropopause following the eruption of Mount St. Helens

A global three-dimensional model of the tropospheric sulfur cycle

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