## 5 Results  
### Evolution of Earth's TOA Radiative Fluxes and EEI Since 2013  
To analyze the evolution of Earth's TOA radiative fluxes, we used monthly global maps of OSRs and OLRs, primarily from the CERES-EBAF dataset at a \(1^{\circ}\times 1^{\circ}\) latitude-longitude resolution. The CERES-EBAF product provides monthly mean fluxes corrected for diurnal cycle sampling and constrained by energy balance based on observations from multiple satellite platforms (Terra, Aqua, and NOAA-20). Although CERES-EBAF fluxes represent monthly averages, they are compared here with monthly means from Uvsq-Sat data, which are based on measurements taken at fixed solar local times (e.g., Uvsq-Sat at 9:30 a.m.) and averaged monthly as well as over multiple-month periods (Figures A1 and A2). To achieve a more consistent comparison, we relied on the SSF1 deg Level 3 CERES data products ([[https://ceres.larc.nasa.gov/data/](https://ceres.larc.nasa.gov/data/)]([https://ceres.larc.nasa.gov/data/](https://ceres.larc.nasa.gov/data/)), accessed on 14 July 2025). Terra Edition 4.1 was employed for the period March 2000 to July 2024, while Edition 4.2 was used for the more recent interval, from August 2023 to October 2024. These datasets provide instantaneous TOA fluxes at the Terra satellite overpass time (10:30 a.m. local solar time). These snapshot measurements are comparable to those obtained by Inspire-Sat (10:30 a.m.) and Uvsq-Sat. In future work, we plan to implement a systematic spatiotemporal colocation methodology to compare CubeSat measurements from Uvsq-Sat and Inspire-Sat with CERES data. Specifically, we will use the CERES SSF1 deg-Hour Terra Edition4A dataset ([[https://asdc.larc.nasa.gov/project/CERES/CER_SSF1](https://asdc.larc.nasa.gov/project/CERES/CER_SSF1) deg-Hour_Terra-MODIS_Edition4A]([https://asdc.larc.nasa.gov/project/CERES/CER_SSF1](https://asdc.larc.nasa.gov/project/CERES/CER_SSF1) deg-Hour_Terra-MODIS_Edition4A), accessed on 28 June 2025) [44], which provides instantaneous TOA radiative fluxes. For the current study, for each month, global mean fluxes were calculated by applying area weighting using the cosine of latitude, ensuring that each grid cell contributes proportionally to its actual surface area on Earth. The periods of interest are from January 2013 to October 2024 for CERES and from February 2021 to October 2024 for Uvsq-Sat. A CERES anomaly was defined as the difference between observed radiative fluxes and a reference climatological mean for the same calendar month. Anomalies for Uvsq-Sat were computed in the same way, using its own baseline period (e.g., 2021-2024), to ensure consistency and comparability with CERES. In the case of Uvsq-Sat, the solar flux was derived from SATIRE-S data, while the NET flux was calculated as the difference between the incoming solar flux and the outgoing OSR and OLR fluxes. The uncertainty in the NET flux was estimated by combining individual error sources in quadrature. To smooth out seasonal cycles and short-term variability in TOA radiative flux anomalies, a 12-month running mean was applied to the monthly anomaly time series from both CERES and Uvsq-Sat. Finally, to ensure a consistent comparison between Uvsq-Sat and CERES measurements, constant offset corrections were applied to the Uvsq-Sat data for the incoming solar flux, OSR, and OLR. These offsets account for small but systematic calibration differences between the satellite instruments. The absolute flux levels measured by Uvsq-Sat over the study period were 105.52 \(\pm\) 5 Wm\({}^{-2}\) for OSR and 236.18 \(\pm\) 5 Wm\({}^{-2}\) for OLR (1\(\sigma\) uncertainty). To focus on temporal variability rather than absolute values, the Uvsq-Sat time-series data were normalized relative to their respective means and adjusted using the following constant offsets derived from the average differences with CERES: +0.17 Wm\({}^{-2}\) for the solar flux (TSI/4), \(-1.10\) Wm\({}^{-2}\) for OSR, and +0.40 Wm\({}^{-2}\) for OLR.