Interaction of photochemical and radiative processes in the stratosphere: An application on the retrieval of concentration profiles from satellite measurements

Abstract

A new method is developed to determine the concentration profiles of chemical species from satellite measurements. The method takes into account the interaction of photochemical and radiative processes in the stratosphere and is applied for chemical species (nitric oxide and nitrogen dioxide) experiencing large diurnal changes. It is found that if the interaction of the photochemical and radiative processes is neglected, that is if the temporal and spatial variations of NO and NO 2 are not considered in the radiative transfer calculations, the resulting errors for the concentration profiles for altitudes less than 20 km reach 100 and 5% respectively, for both sunset and sunrise. A photochemical scheme is developed capable of providing the mixing ratio profiles of NO and NO 2 for different latitudes, altitudes and seasons and a retrieval code combining an iterative inversion algorithm, working from top of the atmosphere downwards, and a parameterization of the variability of NO and NO 2 is also constructed. The method is used to examine the accuracy of the retrieval of the vertical concentration profiles and the new results show that the recovered profiles are in good agreement (error 5–15%) with measured profiles (WMO, 1985) and reflect the trends of NO and NO 2 at sunset and sunrise.