As an addition to carbon stocking, grasslands could also provide an additional leverage against climate change : reduction of radiative forcing though increases in surface albedo. Sentinel-2 satellites offer a global coverage of Earth surface with a high spatial resolution (between 10 and 60 meters for a pixel) and an image frequency of 5 days on average. Sentinel-3 satellites offer images at a lower spatial resolution (300 meter pixels) but at a higher frequency (almost daily images). Combining Sentinel-2 and Sentinel-3 images allows us to produce a high resolution albedo product with sufficient temporal resolution to track monthly changes on agricultural fields over the year. This is the preliminary step to the study of albedo as an attenuation factor for climate change, reducing radiative forcing on exploited grasslands. First results calculated since the beginning of the 2020 summer are presented with comparisons with ground data gathered over a French prairie.