JRC Copernicus climate change service fitness for purpose benchmark platform: GAMMA INDEX

Abstract

This paper introduces a methodology to infer the physical consistency of different remote sensing satellite-based products using the gamma index metrics. In this work the capabilities of the gamma index as a suitable consistency indicator of different satellite products are shown. The method is used in order to support the Copernicus Climate Change Service (C3S) Fitness for Purpose (F4P) benchmarking component. The method is applied to the GlobAlbedo albedo products with similar products generated from MODIS Collection-5 and Copernicus Global Land Service [5] at the global scale. The analysis is conducted in terms of white-sky surface albedo in the visible, near-infrared and shortwave broadband, over the period 2000-2011. Spatial resolution at 0.05° and monthly aggregation of products are considered. The obtained results indicate the need to perform better space-based surface albedo retrievals over snow and ice and more generally during winter.