These space engineers are fast and efficient ! Just a week after our ROSAS station in Lamasquère was erected, we already have the first BRDF measurements, the producing of which required also the processing of calibration sequences. This was done thanks to our colleagues at CNES from the service in charge of measurement physics in optics, especially Lucas Landier, Sebastien Marcq and Aimé Meygret, and the exploitation team (Nicolas Guilleminot). Although the installation of the system has degraded the uniformity of the existing cover crop, the orders of magnitude of reflectances are as expected; and we can even see the shadow of the mast in the 120° azimuth direction in the top-left graph.

Let’s wait for the corn to be sown, and we should have much cleaner BRDFs.


Polar diagrams of surface reflectances measured by our ROSAS station in Lamasquère. In this not very intuitive representation, the 0° azimut corresponds to observations towards the South.  The top left image was taken in the morning, the top right around noon, bottom left in the afternoon, and bottom right later on after the arrival of clouds. The yellow dots indicate the position of the sun. The radius of the graph corresponds to the zenith angle, and the other dimension is the azimuth with regard to the North.



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