First Results From the Rotating Fan Beam Scatterometer Onboard CFOSAT

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Ocean waves are disturbances in the ocean that transmit energy from one place to another. It is an important parameter in the dynamic marine environment. Wave measurements over the oceans are of great significance in modeling and forecasting of weather, ocean surface conditions, ocean circulation, etc. (Zhang et al., 2015). These measurements can be used to improve the understanding of the physical processes responsible for wind-wave evolution, to validate and calibrate models for waves and other ocean processes, and to investigate local and regional wave climate, all of which have the potential to assist in shipping and offshore engineering projects (Durrant et al., 2009). Widely recognized as they are, these measurements were not obtained from space until around 3 decades ago. After the emergence of the satellite altimeter, global monitoring of ocean waves became a reality, with the publication of the first global atlas of significant wave height (SWH) data derived from GEO-3 altimeter data. Since then, SWH data from many different satellites have become available,

Section: Introductionmentioning

confidence: 99%

Validation and Calibration of Nadir SWH Products From CFOSAT and HY‐2B With Satellites and In Situ Observations

Лиу

et al. 2021

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“…It is flying at a low altitude of 519 km on a polar orbit. It carries two radar instruments, including a wind scatterometer (SCAT) developed by the National Space Science Center (NSSC) of the Chinese Academy of Sciences and a wave spectrometer (Surface Wave Investigation and Monitoring, SWIM) provided by CNES (Hauser et al, 2021;J. Liu et al, 2020;Xu et al, 2019).…”

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confidence: 99%

“…Liu et al, 2020;Xu et al, 2019). The above two instruments are operated in Ku-band microwave frequency (13.256 GHz for SCAT and 13.6 GHz for SWIM) to simultaneously observe ocean surface wind at 10 m height and surface wave spectra (Liu et al, 2020). Takin this chance, this study used the global wave data of CFOSAT observations to investigate TC wave distribution's asymmetry.…”

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confidence: 99%

Asymmetric Wave Distributions of Tropical Cyclones Based on CFOSAT Observations

Shi

Chu

et al. 2021

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Tropical cyclones (TCs) are intense low-pressure sources with strong wind forces that cause complex upper ocean conditions such as disastrous ocean waves (Monserrat et al., 2006). There are approximately 80 TCs globally every year, and about two-thirds of these TCs reach the severe scale (McBride, 1995). The waves induced by TC have severe impacts on coastal projects, maritime navigation, and other marine economy industries. Therefore, it is vital to investigate the ocean wave characteristics during TCs. A TC is characterized by cyclonic atmospheric circulation with counterclockwise (clockwise) rotation in the Northern (Southern) Hemisphere, and the motion is controlled by the large environmental flow and β-effect

“…CFOSAT was launched on October 29, 2018 carrying a real‐aperture scanning radar, SWIM. In addition to the wave sensor, CFOSAT also carries a scatterometer to measure sea surface winds (Liu et al., 2020). The SWIM sensor scans the sea surface by six rotating beams at small incidence angles of 0°, 2°, 4°, 6°, 8°, and 10°.…”

Section: Data Setsmentioning

confidence: 99%

Retrieval of Ocean Wave Heights From Spaceborne SAR in the Arctic Ocean With a Neural Network

Huang

2021

Prior to the launch of the Chinese French Oceanic Satellite (CFOSAT) with its onboard Surface Waves Investigation and Monitoring (SWIM) sensor, the only sensor capable of imaging ocean waves in two dimensions from space was the spaceborne synthetic aperture radar (SAR), which provides images with high spatial resolution. The SAR imaging mechanism of ocean waves is complex which is generally explained by three modulations: tilt modulation, hydrodynamic modulation and velocity bunching (Alpers et al., 1981; Valenzuela, 1978). While tilt and hydrodynamic modulations are also shared by real-aperture radar as the dominant imaging mechanisms of ocean waves, velocity bunching is unique for SAR to image ocean waves. The moving scatterer of water particles with a velocity either toward or away from a moving SAR sensor, causes an azimuthal shift in SAR images. In addition, velocity bunching in the SAR resolution cell leads to an azimuth cutoff , that is, the minimum SAR-detectable wavelength of ocean waves traveling in the azimuth direction. Therefore, the nonlinearity of SAR ocean wave imaging complicates their retrieval. In the following, we briefly summarize the existing methods used to retrieve ocean wave information in terms of both two-dimensional spectra and integral wave parameters. The Max Planck Institute (MPI) scheme developed by Hasselmann and Hasselmann (1991) and Hasselmann et al. (1996) is a widely used method to retrieve two-dimensional ocean wave spectra from spaceborne