SCALE PROBLEMS IN GLOBAL TROPOSPHERIC CHEMISTRY MODELING - COMPARISON OF RESULTS OBTAINED WITH A 3-DIMENSIONAL MODEL, ADOPTING LONGITUDINALLY UNIFORM AND VARYING EMISSIONS OF NOX AND NMHC

As a consequence of the non-linear behavior of the chemistry of the atmosphere and because of the short lifetime of NO(X) in the atmosphere, two-dimensional models do not give an adequate description of the production and destruction rates of O3 and the global distributions of the concentrations of O3 and OH. The errors which result were estimated by running a 3-D model both with longitudinally uniform and varying anthropogenic NO and NMHC input rates. It is shown that the latter lead to much lower O3 and especially OH concentrations. The effects are particularly pronounced in the tropics and in the mid-latitude regions of the northern hemisphere. This affects estimates of the atmospheric sink of CH4 and especially deductions about its latitudinal distribution.