Validation of the Grassland Production Index, an Insurance Product Estimated at the National Scale, on a Dense Experimental Device.

Summary This paper aims at comparing satellite-derived and in situ yearly variations of grassland production, over nine farms located in France. During three successive years (2016, 2017, 2018), a dense experimental device has allowed to characterize the variability of grassland production, through a regular survey conducted on more than 169 plots. Ranging from 4.1 to 11.2 t.ha -1 , the yearly production were derived from several tens of thousands of measurements, and combined to derive yearly variations of production. Such unique dataset was compared to a grassland production index, derived from the combined use of medium resolution satellite images and meteorological data. A high level of accuracy is observed between the in situ and the satellite-derived yearly variations of grassland production, with a R 2 of 0.76 and a maximum deviation of 16.3%. Finally, a focus on the maps obtained at the national level makes it possible to analyze the context of the 3 studied years.