A framework is proposed for assessing the physical consistency between two terrestrial Essential Climate Variables (ECVs) products retrieved from Earth Observation at global scale. The methodology assessed the level of agreement between the temporal variations of Leaf Area Index (LAI) and Fraction of Absorbed Photosynthetically Active Radiation (FAPAR). The simultaneous changes were classified according to their sign, magnitude and level of confidence, whereby the respective products uncertainties were taken into consideration. A set of proposed agreement metrics were used to identify temporal and spatial biases of non-coherency, non-significance, sensitivity and the overall level of agreement of the temporal changes between two ECVs. We applied the methodology using the Joint Research Center (JRC) Two-stream Inversion Package (TIP) products at 1 km, those provided by the Copernicus Global Land Service (CGLS) based on the SPOT/VGT and Proba-V at 1 km, and the MODIS MCD15A3 at 500 m. In addition, the same analysis was applied with aggregated products at a larger scale over Southern Africa. We found that the CGLS LAI and FAPAR products lacked consistency in their spatial and temporal changes and were severely affected by trends. The MCD15A3 products were characterized by the highest number of non-coherent changes between the two ECVs but temporal inconsistencies were mainly located over the eastern hemisphere. The JRC-TIP products were highly consistent. The results showed the advantages of physically-based retrieval algorithms, in both JRC-TIP and MODIS products, and indicated also that, except for MODIS over forests, aggregated products using an uncertainty-based weighted average led to higher agreement between the ECVs changes.

提出了一个框架，用于评估从全球范围的地球观测中获取的两个陆地基本气候变量 (ECV) 产品之间的物理一致性。该方法评估了叶面积指数 (LAI) 和吸收光合有效辐射分数 (FAPAR) 的时间变化之间的一致性水平。同时变化根据其符号、幅度和置信水平进行分类，其中考虑了各自的产品不确定性。一组提议的一致性指标用于识别非一致性、非显着性、敏感性和两个 ECV 之间时间变化的总体一致性的时间和空间偏差。我们在 1 公里处使用联合研究中心 (JRC) 两流反演包 (TIP) 产品应用了该方法，这些产品由哥白尼全球陆地服务 (CGLS) 基于 SPOT/VGT 和 Proba-V 在 1 公里处提供，和 MODIS MCD15A3 在 500 m。此外，对南部非洲更大规模的聚合产品也进行了相同的分析。我们发现 CGLS LAI 和 FAPAR 产品在时空变化上缺乏一致性，并且受到趋势的严重影响。MCD15A3 产品的特点是两个 ECV 之间的非相干变化数量最多，但时间不一致主要位于东半球。JRC-TIP 产品高度一致。结果显示了基于物理的检索算法在 JRC-TIP 和 MODIS 产品中的优势，