Preliminary results and validation of a 2D model employing a residual circulation formalism

Summary A two-dimensional, photochemical model of the atmosphere has been developed and valitated with existing experimental data. The reason to develop this model is to predict the concentrations of minor constituents of the atmosphere to be compared with data obtained in an articulate measurement compaign. The originality of our approach is to use a residual mean calculation and a set of eddy diffusion coefficients obtained from a general circulation model of the stratosphere. The advantage of this approach, based on more sound physical basis, is to reduce the importance of the eddy diffusion coefficients. Results are presented for NO _x (NO+NO₂), odd hydrogen, HNO₃, HCl, ClO. They show that the quality of our predictions is comparable to existing parametrized two-dimensional model. We attribute the disagreements to the simplicity of the chemical scheme. Improvements on this scheme and on the treatment of the diurnal variations are planned for this model. Paper presented at the 2^o Convegno Nazionale di Fisica Cosmica, held at L'Aquila, 29 May–2 June 1984.