Stratospheric methane measurements and predictions

Ackerman, M.; Frimout, D.; Müller, C.; Wuebbles, Donald J.

doi:10.1007/bf00876623

Cited by 13 publications

(3 citation statements)

References 11 publications

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“…Muramatsu 1981). This is currently believed to reflect the production of water vapour by the oxidation of methane in the higher stratosphere (Ackerman et al 1979). There is also one possibly significant sink for water in the stratosphere which occurs during the polar winter when temperatures decrease sufficiently to allow cloud to form and persist long enough for particles to settle out of the stratosphere.…”

Section: Introductionmentioning

confidence: 99%

Aircraft measurements of the humidity in the lower stratosphere from 1977 to 1980 between 45°N and 65°N

Foot¹

1984

Quart J Royal Meteoro Soc

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Results are presented of measurements of humidity in the lower stratosphere from a Canberra aircraft of the Meteorological Research Flight using a manually operated frost point hygrometer. From 1977 to 1980, observations were taken routinely between 45 and 65°N so it has proved possible to study both temporal and latitudinal variations. The most striking feature emerging from these analyses is the decrease in variability with increasing latitude. Overall the results appear to indicate that (a) the subtropical jet stream is an important source as well as sink of water vapour to this region; (b) that there may be a sink of water vapour in polar regions; and (c) that the influence of sudden warming events can be detected in water vapour changes at latitudes greater than 50°N. No explanation for an apparently greater probability of unusually high humidity in the north in this range has been possible.

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Section: Introductionmentioning

confidence: 99%

Aircraft measurements of the humidity in the lower stratosphere from 1977 to 1980 between 45°N and 65°N

Foot¹

1984

Quart J Royal Meteoro Soc

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“…Stanford [1973] suggested an additional sink for stratospheric water as condensation and precipitation during the antarctic winter night. Ackerman et al [1977] reviewed the various measurements of stratospheric methane and gave an average profile showing 1.5 parts per million by volume (ppmv) at 12 km and about 0.1 ppmv at 45 km. This decrease of mixing ratio with altitude demonstrates in a direct manner the destruction of methane in the upper atmosphere.…”

Section: Introductionmentioning

confidence: 99%

Thunderstorms as possible micrometeorological sink for stratospheric water

Johnston¹,

Solomon²

1979

J. Geophys. Res.

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The dryness of the stratosphere has been explained, in general terms, as water condensation from the rising branch of the Hadley cell at the tropical tropopause (Brewer, 1949), but Ellsaesser (1974) suggested that the mean tropical tropopause is not cold enough to account for the observed water vapor mixing ratios. During intense thunderstorms that in part penetrate the tropopause, investigators have observed (1) an increase in local stratospheric water vapor and (2) the temporary presence of air parcels substantially colder than and higher than the tropopause. These cold parcels are calculated to have extremely low water vapor mixing ratios, and their occurrence in the stratosphere suggests a mechanism whereby the effective condensation temperature could be systematically colder than the tropopause. Ice crystals from the cloud, evaporating in the warmer stratosphere, presumably cause the observed increase in water vapor, but mixing of cold desiccated air parcels with lower stratospheric air would tend to decrease its water content. Thus there are opposing factors concerning the role of severe cumulonimbus storms on stratospheric water, and it may require detailed, microphysical analysis to see which effect is larger.

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“…At 14 km, ozone is destroyed by Ox reactions 5 times faster than it is produced by oxygen photolysis (L/P), but the ozone relaxation time r at 14 km is 51 years, which demonstrates that the large value of L/P is not significant at this altitude. [Ackerman, 1977] and Observed Hydroxyl Radicals [Anderson, 1976] much higher percentages at lower elevations. The ratio between column loss, 20-35 km, and column production over the same range is 1.14.…”

Section: Odd Oxygen Destruction By Ozonementioning

confidence: 82%

Interpretations of stratospheric photochemistry

Johnston¹,

Podolske²

1978

Reviews of Geophysics

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Trace stratospheric species (parts per billion or less) have negligible effects on ozone (parts per million) unless they interact in catalytic cycles that regenerate the trace species. It is appropriate to regard catalytic cycles, null cycles, and consumptive sequences, rather than the elementary chemical reactions, as the components of ozone photochemistry. A general differential equation for ozone is transformed to an equivalent equation that directly identifies the catalytic cycles and sequences. The novel aspect of this article is the completeness with which this transformation is carried out and used. This method of treating stratospheric photochemistry properly partitions ozone destruction rates among Ox, NOx, HO•, and CIX families of reactions. The features of the methane-smog chemistry are clearly brought out. From the midvalues of published measurements of NO2 and CIO, it appears that NO2, CIO, and O8 are sufficient to destroy ozone as fast as it is formed in the range 23-35 km, and NO• reactions and CIX reactions appear to be roughly equal in importance. There is no need to invoke any new or unknown sink for ozone in this region if the midvalues of measured NO2 and CIO are rep?esentative of the global average. It is improbable that the high values observed for NO2 or for CIO are representative of global average values. The magnitude of the contribution of HO• reactions to ozone photochemistry cannot be found by this method because of lack of observations of HOO in the stratosphere. These conclusions depend on the accuracy of the stratospheric observations and certain rate constants. Additional measurements are needed, especially for HOO, NO2, CIO, and HO. CONTENTS

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Stratospheric methane measurements and predictions

Cited by 13 publications

References 11 publications

Aircraft measurements of the humidity in the lower stratosphere from 1977 to 1980 between 45°N and 65°N

Aircraft measurements of the humidity in the lower stratosphere from 1977 to 1980 between 45°N and 65°N

Thunderstorms as possible micrometeorological sink for stratospheric water

Interpretations of stratospheric photochemistry

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