ORBITING AND GROUND RFI MITIGATION STRATEGY IN MICAP L-BAND INTERFEROMETRIC RADIOMETER
Marzo 25, 2026THE MIRADOR PROJECT: ENHANCING THE ASSESSMENT OF OFFSHORE WIND RESOURCES WITH MICROWAVE RADIOMETERS
Marzo 25, 2026J. Boutin1, J. Vergely2, S. Ferron2, L. Bertino3, G. Macelloni4, M. Brogioni4, M. Leduc-Leballeur 4, F. Montomoli4, M. Drusch5, T. Casal5, M. Fréry6
1LOCEAN/CNRS, 2ACRI-st, 3NERSC, 4IFAC, 5ESA, 6CNES
The salinity of polar oceans is undergoing significant changes due to sea ice melt and increased continental runoff, which have resulted in a decrease in sea surface salinity (SSS) across most regions of the Arctic Ocean, intensifying upper ocean stratification. In the Southern Ocean, changes in the extent and thickness of Antarctic sea ice are also striking, and are also linked to SSS changes. These shifts profoundly impact ocean circulation, the ocean’s capacity to absorb atmospheric heat and carbon, and ultimately, Earth’s climate. However, current climate models struggle to accurately represent high-latitude water mass properties.
SSS is recognized as an Essential Climate Variable (ECV) by the Global Climate Observing System (GCOS). While current 1.4 GHz radiometer missions have revolutionized global SSS measurements at scales of 40–150 km with revisit intervals of 3 to 8 days, their sensitivity to SSS diminishes by a factor of ~3 between 30°C and 0°C, leading to large SSS uncertainties in polar regions.
The CryoRad mission, an ESA Earth Explorer 12 mission idea selected for a Phase 0 , features a radiometer with an extended frequency range of 0.4–2 GHz, designed to improve SSS measurement accuracy in cold waters.
As part of the CNES study on “Salinity Estimation in Cold Seas Using Multiband 0.4–2 GHz” and the ESA CryoRad Phase 0 Science and Requirements Consolidation Study (SciReC), we conducted simulations of retrieved SSS uncertainties, considering various instrumental configurations and various environmental factors such as sea surface temperature, wind speed, which were modeled using radiative transfer components validated for L-band and extrapolated to lower frequencies. These simulations demonstrate the potential of a 0.4-2GHz wideband mission to enhance SSS retrieval at high latitudes. Both the random and the systematic uncertainties are reduced by a factor 3 with respect to L-Band radiometry, with an even better improvement at moderate SSS (<25pss).
Our presentation will detail academic simulations and performances achieved in estimating SSS within the context of high latitude environmental conditions. A flight campaign with an instrument simulator (LoMiRad) took place in the Bay of Baffin in August 2025. When relevant, comparisons of simulated radiometric brightness temperatures with airborne data will be discussed.
