What is the effect of cloud inhomogeneities on actinic fluxes and chemical species concentrations?

The purpose of the present paper is to evaluate the bias introduced by the commonly used homogeneous plane-parallel cloud hypothesis in the computation of actinic fluxes, photolysis coefficients, and main tropospheric species concentrations. Accordingly, these quantities obtained for an inhomogeneous cloud field generated with a stochastic model are compared to their homogeneous plane-parallel equivalent. Results show that neglecting cloud inhomogeneities has a significant impact on actinic flux. For instance, the bias introduced by the homogeneous plane-parallel cloud hypothesis can reach more than 100% below the cloud leading to a comparable bias in photolysis coefficients and, in turn, creating an enhancement of the oxidizing capacity of the system.