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A two‐dimensional chemical model of the atmosphere is described. The model includes the major features associated with advanced one‐dimensional models: 30 active chemical species and all the important chemical reactions connecting them, diurnal effects, and Rayleigh scattering. The species are transported and calculated separately, with the exception of the odd oxygen family [O3, O(3P), O(1D)] and H and N atoms. The transport scheme contains both diffusive and advective terms, with the advective circulation field of Murgatroyd and Singleton (appropriately scaled) used to approximate the Lagrangian mean flow. Comparison of the model predictions with atmospheric observations of long‐lived trace species such as O3, N2O, CF2Cl2, CFCl3, and CH4 suggests that the transport parameterization gives a good representation of actual trace species motions. For constituents which are more active or whose chemistry is less well known, the model is a useful diagnostic tool for assessing our current understanding of atmospheric chemistry. A number of significant discrepancies between experiment and theory are highlighted, the most important being in the Clx and NOy families.

An atmosphere model composed of a narrow band radiative-convective (RC) code coupled with a one-dimensional chemistry and transport code is described. The RC model, formulated in log-pressure coordinates, includes accurate solar absorption calculations for 0 3, 02, H20, and CO 2. Infrared heating and cooling by CO 2, 0 3, and H20 are calculated with a narrow band formulation, while broader band formulations are used for CH,•, N20, CFC 11, and CFC 12. The atmospheric chemistry and transport model uses photochemical reaction rate data from Jet Propulsion Laboratory publication 82-57. The calculated steady state atmospheric response to several potential perturbations is discussed. Doubling the atmospheric CO 2 level yields a change in total ozone of + 2.9% and a surface temperature increase of 1.7 K. The continued release of chlorofluorocarbons (CFC's) alone at nominal rates gives a calculated column ozone change of -5.7% at steady state, while for a combined 2 x CO 2 + CFC perturbation the result is -3.5%. Ozone perturbations due to increases in N20, CH,•, and aircraft are also discussed. Two coupled scenarios including projected changes that may occur in about 100 years due to all these identified man-made perturbations are discussed. The calculated ozone column changes are -4.5% and + 1.5%, assuming fixed and doubled methane source strengths, respectively.

From the hourly counting rate of the Deep River neutron monitor we have calculated the magnitude and phase of the diurnal anisotropy, and from them we have inferred the magnitude and direction of cosmic ray diffusion on a daily basis. These data are compared with observed interplanetary magnetic field data, and we conclude that the diffusion is field aligned (within observational uncertainties) on essentially all days which are separated from sector boundaries. Days in which diffusion does not appear field aligned are characterized either by sector boundaries or by poor statistical accuracy.