The Israeli and French VENµS satellite is a small research satellite designed to test two innovative missions : an optical mission with a frequent revisit on the French side, and an experiment of a Ion Thruster to maintain the satellite at a low altitude on the Israeli side. Of course, we did not manage to […]
=> When the summers were hot and dry during the past years, our monthly cloudfree syntheses of surface reflectances from Sentinel-2 for the month of July interested the media. It will probably not be the case in 2021, as France thankfully kept its green colour in July. Because of the cloud cover that […]
A few years only after its worst drought in 1,200 years (2011-2016), the drought returns to California. Lake Oroville is both a witness and a victim of the extreme hydro-meteorological variability in the Golden State. It provides water to « homes, farms, and industries in the San Francisco Bay area, the San Joaquin Valley and Southern […]
This post intends to answer a question about Sentinel-HR, that we have had quite often inside or outside CNES : Securing continuity in a critical timeseries requires user community foresight, Programme justification, 10 yrs Agency prep, and finances. Whilst Sentinel-HR may well be an excellent/valid idea, I’m left asking why certain Copernicus contributing missions couldn’t […]
=> If you are working with Sentinel2 products, you probably heard that ESA new geometric processing is active since 1st of April 2021. This new processing, based on the geometric refinement of viewing parameters with respect to a Global Reference Image (GRI), should bring absolute location error from 11 meters (95.5% of products) to better […]
=> Field work rarely goes without a few small hazards. In the case of our new ROSAS station, newly installed a month ago, the hazard unfortunately took the form of a farm machine hitting the mast while tilling the soil on April 15th. The base of the mast twisted under the impact, leaving the structure […]
The distribution of MAJA L2A processor, as an executable software, started in april 1997, but we started counting the number of downloads only since October 2017. The cumulative number of downloads just reached 2000 on April the 2nd 2021. It is on average 1.56 downloads per day, and more than 2 downloads per work day […]
=> Here is a frequently asked question : I noticed, in such L2A product processed by MAJA, that some pixels had negative reflectances, is it normal ? No, it should not happen, but the fact it happens is not entirely surprising, I will explain it below. Unlike negative reflectances, reflectances greater than one can exist, […]
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 […]