Ice Concentration Retrieval from the Analysis of Microwaves: Evaluation of a New Methodology Optimized for the Copernicus Imaging Microwave Radiometer

• Published in: Remote Sensing
• Main Authors: Prigent, Catherine, Kilic, Lise, Aires, Filipe, Pellet, Victor, Jimenez, Carlos
• Other Authors: Sorbonne Université (SU)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2020
• Subjects: Sea ice concentration; Passive microwaves; Inversion; Optimal estimation; Copernicus Imaging Microwave Radiometer; [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; Sea ice
• Online Access: https://hal.sorbonne-universite.fr/hal-03045716; https://hal.sorbonne-universite.fr/hal-03045716/document; https://hal.sorbonne-universite.fr/hal-03045716/file/IceCREAM_evaluation_revised_clean.pdf; https://doi.org/10.3390/rs12101594

International audience A new methodology has been described in Kilic et al. [1] (Part 1 of this study) to estimate Sea Ice Concentration (SIC) from satellite passive microwave observations between 6 and 36 GHz. The Ice Concentration REtrieval from the Analysis of Microwaves (IceCREAM) algorithm is based on optimal estimation, with a simple radiative transfer model derived from satellite observations at 0 and 100% SIC. Observations at low and high frequencies have different spatial resolutions, and a scheme is developed to benefit from the low errors of the low frequencies and the high spatial resolutions of the high frequencies. This effort is specifically designed for the Copernicus Imaging Microwave Radiometer (CIMR) project, equipped with a large deployable antenna to provide a spatial resolution of ∼5 km at 18 and 36 GHz, and ∼15 km at 6 and 10 GHz. The algorithm is tested with AMSR2 observations, for a clear scene over the north polar region, with collocated MODIS estimates and the OSI SAF operational product. Several algorithm options are tested, and the study case shows that both high spatial resolution and low errors are obtained with the IceCREAM method. It is also tested for the full polar regions, winter and summer, under clear and cloudy conditions. Our method is globally applicable, without fine-tuning or further weather filtering. The systematic use of all channels from 6 to 36 GHz makes it robust to changes in ice surface conditions and to weather interactions.