Uncertainties in Stratospheric–Mesospheric Modeling

McConnell, J. C.

doi:10.1139/v74-235

Cited by 5 publications

(1 citation statement)

References 20 publications

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“…1972], it is not yet clear how to détermine the intermediate paths and their effect on ozone equilibrium [Nicolet, 1974;Crutzen. 1974û;McConnell. 1974], Figure 7 shows how CH3O2, CHaO.…”

Section: Reactions After Oxidation Of Méthanementioning

confidence: 99%

Stratospheric Ozone: An Introduction to Its Study

Series

1976

1976, Chemistry and Physics of the Stratosphere

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An analysis is made of the varions re actions in which ozone and atomic oxyge n are involve d in the stratosphère. At the présent time, hydrogen. nitrogen. and chlorine compounds in the ranges parts per million, parts per billion, and parts per I rillion may have significant chemical effects. I n the upper stratosphère, above the ozone peak. where there is no slrong departure from photochemical equilibrium conditions, the action of hydroxyl arid hydroperoxyl radicals of nitrogen dioxide and chlorine monoxide on atomic oxygen and of atomic chlorine on ozone can be introduced. A précise détermination of their ex act effects requires Knowledge of (1) the vertical distribution of the HjO. CH,. and Hj dissociation by reaction of thèse molécules with electronically excited oxygen atom OCf): (2) the ratio of the OH and HOj concentrations and their absolute values, which dépend on insufficiently known rate coefficients: (3) the various origins of nitric oxide production, with their vertical distributions relaled to latitude and season; and (4) the various sources giving différent chlorine compounds lhat may be dissociated in the stratosphère. I n the lower stratosphère, below the ozone peak. there is no important photochemical production of Oj, but there exist various possibilities of transport. The prediclability of the action of chemical reactions dépends strongly on important interactions between OH and HOj radicals with CO and NO. respectively. which affect the ratio n(OH)/n(\\Oi) at the tropopause level; between OH and NOj. which lead to the formation of nitric acid with its downward transport toward the troposphère; between NO and HO2. which lead to NO? and its subséquent photodissociation; between CI O and NO. which also lead to NOj and become more important than the reaction of CI O with O; and between Cl and various molécules, such as CH. and Hj, which lead to HCl with its downward transport toward the troposphère. Ail thèse chemical processes are subjeci to many changes since they occur in the lower stratosphère where seasonal. latiludinal, and even daytoday variations of the ozone concentrations are observed in associa tion with advective and dynamic transports, which dépend on meteorological conditions as indicated by variations of tropopause heights.

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“…1972], it is not yet clear how to détermine the intermediate paths and their effect on ozone equilibrium [Nicolet, 1974;Crutzen. 1974û;McConnell. 1974], Figure 7 shows how CH3O2, CHaO.…”

Section: Reactions After Oxidation Of Méthanementioning

confidence: 99%

Stratospheric Ozone: An Introduction to Its Study

Series

1976

1976, Chemistry and Physics of the Stratosphere

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Possible existence and role of excited ozone precursors in the stratosphere

Prasad

Burton

1979

Planetary and Space Science

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Stratospheric ozone: An introduction to its study

Nicolet¹

1975

Reviews of Geophysics

166

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An analysis is made of the various reactions in which ozone and atomic oxygen are involved in the stratosphere. At the present time, hydrogen, nitrogen, and chlorine compounds in the ranges parts per million, parts per billion, and parts per trillion may have significant chemical effects. In the upper stratosphere, above the ozone peak, where there is no strong departure from photochemical equilibrium conditions, the action of hydroxyl and hydroperoxyl radicals of nitrogen dioxide and chlorine monoxide on atomic oxygen and of atomic chlorine on ozone can be introduced. A precise determination of their exact effects requires knowledge of (1) the vertical distribution of the H2O, CH4, and H2 dissociation by reaction of these molecules with electronically excited oxygen atom O(¹D); (2) the ratio of the OH and HO2 concentrations and their absolute values, which depend on insufficiently known rate coefficients; (3) the various origins of nitric oxide production, with their vertical distributions related to latitude and season; and (4) the various sources giving different chlorine compounds that may be dissociated in the stratosphere. In the lower stratosphere, below the ozone peak, there is no important photochemical production of O3, but there exist various possibilities of transport. The predictability of the action of chemical reactions depends strongly on important interactions between OH and HO2 radicals with CO and NO, respectively, which affect the ratio n(OH)/n(HO2) at the tropopause level; between OH and NO2, which lead to the formation of nitric acid with its downward transport toward the troposphere; between NO and HO2, which lead to NO2 and its subsequent photodissociation; between ClO and NO, which also lead to NO2 and become more important than the reaction of ClO with O; and between Cl and various molecules, such as CH4 and H2, which lead to HCl with its downward transport toward the troposphere. All these chemical processes are subject to many changes since they occur in the lower stratosphere where seasonal, latitudinal, and even day‐to‐day variations of the ozone concentrations are observed in association with advective and dynamic transports, which depend on meteorological conditions as indicated by variations of tropopause heights.

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Uncertainties in Stratospheric–Mesospheric Modeling

Cited by 5 publications

References 20 publications

Stratospheric Ozone: An Introduction to Its Study

Stratospheric Ozone: An Introduction to Its Study

Possible existence and role of excited ozone precursors in the stratosphere

Stratospheric ozone: An introduction to its study

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