Seamless Continuity in CERES Energy Balanced and Filled (EBAF) Surface Radiation Budget across Multiple Satellites

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Abstract Achieving multidecadal seamless continuity in the surface radiation budget derived from satellite observations and ancillary input datasets is challenging owing to changes in the input data stream with time. We present a revision of the Clouds and the Earth’s Radiant Energy System (CERES) Energy Balanced and Filled surface irradiance product that overcomes this challenge by limiting the input cloud property information used in deriving surface irradiances to imagers on sun-synchronous orbits. We show that cloud properties derived from Terra and Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) are sufficient to produce accurate and seamless regional monthly mean surface shortwave and longwave irradiances with time. Although a single sun-synchronous orbit introduces significant bias in surface irradiances for regions with strong cloud diurnal cycles, monthly regional surface anomalies align with those from two sun-synchronous orbits. In transitioning the CERES record to and from the combined Terra and Aqua period to one sun-synchronous satellite (e.g., Terra-only period from March 2000 through July 2002 and NOAA-20-only period from April 2022 onward), therefore, regional surface irradiance climatological means derived from one sun-synchronous orbit are adjusted to match the corresponding climatological means derived from Terra + Aqua. The climatological adjustment places surface irradiances of the Terra-only and NOAA-20-only periods on the same radiometric scale as surface irradiances of the Terra + Aqua period. While the uncertainty in regional mean irradiances is the same as the uncertainty in the previous version (edition 4.1), the regional surface irradiance anomaly time series is significantly improved, especially for longwave downward irradiances. Significance Statement The diurnal cycle of clouds influences the top-of-atmosphere and surface radiative energy budget. The study shows that cloud observations taken from two sun-synchronous orbits 3 h apart in mean local equator crossing time around local solar noon are sufficient to capture cloud diurnal cycles to compute the regional (1° × 1°) surface radiative energy budget. The bias of regional surface irradiance computed with one sun-synchronous observation is nearly constant with time. Observations from one sun-synchronous orbit are, therefore, sufficient to capture the variability of the regional surface radiation budget. These key results are used to extend the time period of the Clouds and the Earth’s Radiant Energy System surface radiation budget climate data over the time period consisting of observations taken from multiple satellites.

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