Fusing ground measurements and satellite-derived products for the construction of climatological maps in atmosphere optics

Climatological maps (gridded data) of optical parameters of the atmosphere often result from application of numerical models or processing of satellite images. Such maps usually exhibit very large cell sizes, of the order of V of arc angle. There is a need to increase their spatial resolution to obtain a cell size closer to the spatial representation obtained by standard meteorological instruments at ground level, i.e. 5' of arc angle. It then permits to fuse ground measurements and gridded data, especially to correct for bias observed in gridded data. Taking advantage of the availability of other data sets of relevance to the parameter under concern, though different, a method is proposed for the synthesis of the initial gridded data at a higher resolution by the means of a fusion process. This paper describes the method with an application for the construction of worldwide maps of the Linke turbidity factor with cells of 5' in size. This factor characterises the atmospheric optical turbidity under clear skies and is a very important parameter in solar radiation studies.