Method for Consistency Analysis of a set of space-borne Climate Data Records: Application to Aerosol Optical Depth

Abstract. The consistency of a set of satellite observations obtained with different algorithms from the same satellite instruments can be used as an indicator for their robustness or reliability. For this four metrics to evaluate those characteristics are defined and integrated into one overall consistency score per grid cell. These four metrics are: their median values, annual cycle, median values, decadal trends and correlation. This paper discusses how a combination of these metrics can be used to evaluate the overall consistency of different datasets for the same essential climate data variable.

This study performs an examplary application of this approach on Aerosol Optical Depth (AOD) Climate Data Records (CDRs) obtained from a series of 3 similar instruments from the Copernicus Climate Change Service (C3S). Assessing the consistency of those CDRs is highly relevant because space-based aerosol information and their climate impact have substantial uncertainties. The regional dependency of this consistency score shows the influence of surface properties and geographic regions. With the consistency score, regions with robust information can be separated from more challenging regions and the advantages and disadvantages of different instruments can be identified.