Analysis of Data-Derived SeaWinds Normalized Radar Cross-Section Noise

• Published in: Remote Sensing
• Main Authors: Grieco, Giuseppe, Stoffelen, Ad, Verhoef, Anton, Vogelzang, J., Portabella, Marcos
• Other Authors: European Organisation for the Exploitation of Meteorological Satellites, Ministerio de Ciencia, Innovación y Universidades (España), Agencia Estatal de Investigación (España)
• Format: Article in Journal/Newspaper
• Language: English
• Published: Multidisciplinary Digital Publishing Institute 2022
• Subjects: SeaWinds; Normalized radar cross-section noise; Wind; Sea ice
• Online Access: http://hdl.handle.net/10261/282087; https://doi.org/10.3390/rs14215444; https://doi.org/10.13039/501100011033; https://doi.org/10.13039/501100010560

Special Issue Remote Sensing of the Sea Surface and the Upper Ocean.-- 16 pages, 11 figures, 2 tables.-- Data Availability Statement: The data used in the paper are available from the PODAAC website with url: https://podaac-opendap.jpl.nasa.gov/opendap/, accessed on 30 September 2022 The normalized standard deviation (Kp) of the noise that affects scatterometer Normalized Radar Cross-Sections (σ0s) plays a key role in the ocean and more in particular coastal wind retrieval procedures and the a posteriori quality control. This paper presents a method based on SeaWinds measurements to estimate Kps. The method computes the standard deviation of the differences between the full-resolution (slice) σ0s and the footprint (egg) σ0. The results are compared to the median of Kps provided with SeaWinds σ0s, showing some non-negligible differences. Kps estimated on non-homogeneous surfaces are larger than those estimated on sea, whereas no differences are appreciated in the provided Kps, which is likely due to the ability of this methodology to account for the effect of the scene variability in the estimates. The presence of inter-slice biases is demonstrated with a trend with the antenna azimuth angle. A multi-collocation slice cross-calibration procedure is suggested for the retrieval stage. Finally, a theoretical model of the distribution of σ0s is proposed and used to validate Kps. The results prove the efficacy of this model and that the provided Kps seem to be largely underestimated at low-wind regimes This work was supported in part by the European Organization for the Exploitation of Meteorological Satellites Ocean and Sea Ice Satellite Application Facility (EUMETSAT OSI-SAF) projects under reference VS20_01, VS20_03, and VS21_03, and in part by project INTERACT (PID2020-114623RB-C31), which is funded by MCIN/AEI/10.13039/501100011033 With the institutional support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S) Peer reviewed