# UVSQ-SAT, a Pathfinder CubeSat Mission for Observing Essential Climate Variables
## 4 Results  
This Section presents EEI UVSQ-SAT's expected results and spatial reconstruction of Earth's net radiation. The instrumental requirements for EEI scientific relevance output (absolute uncertainty of \(\pm 1\) Wm\({}^{-2}\) at 1\(\sigma\), stability per decade of \(\pm 0.1\) Wm\({}^{-2}\) at 1\(\sigma\), small spatiotemporal scales with an uncertainty at 1\(\sigma\) of \(\pm 1\) Wm\({}^{-2}\) for a 1-10 km resolution) and UVSQ-SAT instrument performances do not match. At the present stage, the UVSQ-SAT CubeSat is a demonstrator, expecting future developments and improvement that would then really allow making use of CubeSat technology for scientific purposes. What are lacking at the present state to obtain accurate relevant EEI absolute value are the extreme cleanliness CubeSat control (careful material selection (e.g., high radiation tolerance, ultra-high vacuum material quality with lowest outgassing values), minimization of organic material (bake-out), and stringent cleanliness procedures of all hardware), intensive CubeSat pre-flight calibration (achieved with detectors and transfer radiation source standards, both traceable to a primary standard source found in synchrotron radiation facilities, while the sensors themselves can be calibrated at the synchrotron facility or locally, at the instrument test facility, by transporting a transfer source standard to that facility), active ADCS, additional narrowband sensors, atomic clock for synchronization, and in-flight calibration to monitor sensors' aging in space. It is important for continuous monitoring of the ERB (as for CERES, EarthCARE, Megha-Tropiques, and Scanner for Radiation Budget (ScaRaB)) and temporal overlap to realize inter-calibrations. It lacks also a high frequency and sampling in measurements and consequently a more accurate determination of the Earth's global energy imbalance along with the diurnal and multi-directional sampling needed to capture spatiotemporal scales. A constellation consisting of small CubeSat's could provide temporal and spatial coverage that are lacking currently to provide accurate EEI measurements and represent important developments that are needed. The UVSQ-SAT mission will contribute to these future developments both in terms of technology advancement (miniaturized sensors used for high scientific relevance) and innovative data processing (reconstruction of a global map of OLR and OSR using multiple sensors' data). A preliminary analysis of the expected results with a spatial reconstruction of Earth's net radiation that will be obtained with UVSQ-SAT for a given time period of observation was done (Figure 6). The method used to carry out this study is briefly described below:  
1. Use of CERES data (1\({}^{\circ}\times\)1\({}^{\circ}\) latitude-longitude geographic grid, monthly mean) to have an initial map of Earth's net radiation for analysis. Then, we considered that this map corresponded to Earth's net radiation \"real\" map at time t (Figure 6, left upper panel). This map illustrates the fundamental imbalance between net radiation surpluses at the Equator and net radiation deficits at high latitudes. 2. We calculated the UVSQ-SAT CubeSat ground-track (SSO LEO orbit) for a given period (Figure 6, right upper panel). 3. We considered that the maximum angle of view of the UVSQ-SAT sensors can effectively detect the net radiation in a ground area of 1\({}^{\circ}\times\)1\({}^{\circ}\) along the ground-track and for a given acquisition integration time. Then, we obtained Earth's net radiation associated with the sensors' observations. Finally, we performed an interpolation (Delaunay triangulation) on the scattered dataset that resided in 2D space to obtain Earth's net radiation based on UVSQ-SAT observations for a given time period (Figure 6, left middle and bottom panels). 4. We plotted the differences (Figure 6, right middle and bottom panels) between the \"real\" map (Figure 6, left upper panel) and the map obtained with the satellite observations for a given period (Figure 6, left middle and bottom panels).