WACCM-D Whole Atmosphere Community Climate Model with D-region ion chemistry

Energetic particle precipitation (EPP) and ion chemistry affect the neutral composition of the polar middle atmosphere. For example, production of odd nitrogen and odd hydrogen during strong events can decrease ozone by tens of percent. However, the standard ion chemistry parameterization used in atmospheric models neglects the effects on some important species, such as nitric acid. We present WACCM-D, a variant of the Whole Atmosphere Community Climate Model, which includes a set of lower ionosphere (D-region) chemistry: 307 reactions of 20 positive ions and 21 negative ions. We consider realistic ionization scenarios and compare the WACCM-D results to those from the Sodankylä Ion and Neutral Chemistry (SIC), a state-of-the-art 1-D model of the D-region chemistry. We show that WACCM-D produces well the main characteristics of the D-region ionosphere, as well as the overall proportion of important ion groups, in agreement with SIC. Comparison of ion concentrations shows that the WACCM-D bias is typically within ±10% or less below 70 km. At 70–90 km, when strong altitude gradients in ionization rates and/or ion concentrations exist, the bias can be larger for some groups but is still within tens of percent. Based on the good agreement overall and the fact that part of the differences are caused by different model setups, WACCM-D provides a state-of-the-art global representation of D-region ion chemistry and is therefore expected to improve EPP modeling considerably. These improvements are demonstrated in a companion paper by Andersson et al

Influence des ions négatifs sur la diffusion incohérente d'une onde électromagnétique dans la région D de l'ionpsphère terrestre

Doctorat en Sciencesinfo:eu-repo/semantics/nonPublishe

Mesures des sections efficaces d'absorption de constituants atmosphériques dans l'ultraviolet : description du système expérimental

The technical method, the operation and performance of an instrument for laboratory measurements of absorption cross sections in the spectral ultraviolet range are described. Details are given for an application to atmospheric constituents.Wisemberg J., Vanlaethem-Meurée Nicole. Mesures des sections efficaces d'absorption de constituants atmosphériques dans l'ultraviolet : description du système expérimental. In: Bulletin de la Classe des sciences, tome 64, 1978. pp. 21-30

Absorption des chlorométhanes dans l'ultraviolet : mesures des sections efficaces d'absorption en fonction de la température

The absorption cross sections of chloromethanes, CH3Cl, CH2Cl2, CHCI3 and CCI4, leading to their photodissociation by ultraviolet radiation in the stratosphere are presented for spectral ranges of 2 nm and 500 cm-1, respectively, from 175 to 250 nm, and compared with results of other authors. The temperature effects on the absorption cross sections near the threshold are investigated.Vanlaethem-Meurée Nicole, Wisemberg J., Simon P. C. Absorption des chlorométhanes dans l'ultraviolet : mesures des sections efficaces d'absorption en fonction de la température. In: Bulletin de la Classe des sciences, tome 64, 1978. pp. 31-41

Influence de la température sur les sections efficaces d'absorption des chlorofluorométhanes dans l'ultraviolet

The ultraviolet absorption spectrum of CF3Cl, CF2Cl2 and CFCl3has been studied from 175 to 220 nm at various temperatures. Absorption cross sections for T = 296 K, 279 K and 255 K are presented for spectral intervals of 2 nm and 500 cm-1, respectively. The temperature effects on the absorption cross section values are discussed and compared with results obtained by other authors.Vanlaethem-Meurée Nicole, Wisemberg J., Simon P. C. Influence de la température sur les sections efficaces d'absorption des chlorofluorométhanes dans l'ultraviolet. In: Bulletin de la Classe des sciences, tome 64, 1978. pp. 42-51

Operations of ISS payloads at the Belgian User Support and Operation Centre

info:eu-repo/semantics/publishe