Null Variance Altitudes for the photolysis rate constants of species with barometric distribution: Illustration on Titan upper atmosphere modeling
Language
en
Article de revue
This item was published in
Icarus. 2012-04, vol. 218, n° 2, p. 950-955
Elsevier
English Abstract
The precision of the rates of the photolysis processes initiating the complex chemistry of Titan's upper atmosphere conditions strongly the predictivity of photochemical models. Recent studies in sensitivity analysis of ...Read more >
The precision of the rates of the photolysis processes initiating the complex chemistry of Titan's upper atmosphere conditions strongly the predictivity of photochemical models. Recent studies in sensitivity analysis of such models point out photolysis rate constants as key parameters. However, they have been treated approximately so far. We deal here directly with uncertainty in the absorption cross-sections to derive the uncertain altitude-dependent photolysis rate constants. We observe that the uncertainty on the photolysis rate constants of the major species, N2 and CH4, varies strongly with altitude and rather surprisingly vanishes at specific altitudes. We propose a simple model to interpret these features and we demonstrate that they are transferable to any major absorber distributed barometrically in an atmosphere.Read less <
Origin
Hal imported