scholarly journals Technical Evaluation of Sentinel-1 IW Mode Cross-Pol Radar Backscattering from the Ocean Surface in Moderate Wind Condition

2017 ◽  
Vol 9 (8) ◽  
pp. 854 ◽  
Author(s):  
Lanqing Huang ◽  
Bin Liu ◽  
Xiaofeng Li ◽  
Zenghui Zhang ◽  
Wenxian Yu
Keyword(s):  
Ocean Surface ◽  
Wind Condition ◽  
Technical Evaluation ◽  
Radar Backscattering

Three-scale Radar Backscattering Model of the Ocean Surface Based on Second-order Scattering

PIERS Online ◽  
2008 ◽  
Vol 4 (2) ◽  
pp. 171-175 ◽  
Author(s):  
Ying Yu ◽  
Xiao-Qing Wang ◽  
Min-Hui Zhu ◽  
Jiang Xiao
Keyword(s):  
Ocean Surface ◽  
Second Order ◽  
Radar Backscattering

scholarly journals Ocean Surface Roughness Spectrum in High Wind Condition for Microwave Backscatter and Emission Computations*

2013 ◽  
Vol 30 (9) ◽  
pp. 2168-2188 ◽  
Author(s):  
Paul A. Hwang ◽  
Derek M. Burrage ◽  
David W. Wang ◽  
Joel C. Wesson
Keyword(s):  
Remote Sensing ◽  
Surface Roughness ◽  
Surface Waves ◽  
Microwave Remote Sensing ◽  
Ocean Surface ◽  
Short Wave ◽  
Wind Condition ◽  
Bragg Resonance ◽  
High Wind ◽  
Radar Backscatter

Abstract Ocean surface roughness plays an important role in air–sea interaction and ocean remote sensing. Its primary contribution is from surface waves much shorter than the energetic wave components near the peak of the wave energy spectrum. Field measurements of short-scale waves are scarce. In contrast, microwave remote sensing has produced a large volume of data useful for short-wave investigation. Particularly, Bragg resonance is the primary mechanism of radar backscatter from the ocean surface and the radar serves as a spectrometer of short surface waves. The roughness spectra inverted from radar backscatter measurements expand the short-wave database to high wind conditions in which in situ sensors do not function well. Using scatterometer geophysical model functions for L-, C-, and Ku-band microwave frequencies, the inverted roughness spectra, covering Bragg resonance wavelengths from 0.012 to 0.20 m, show a convergent trend in high winds. This convergent trend is incorporated in the surface roughness spectrum model to improve the applicable wind speed range for microwave scattering and emission computations.

Radar backscattering measurements of a simplified rough ocean surface

2019 ◽  
Author(s):  
Abigail Gilmore ◽  
Brian W. Soper ◽  
Thomas M. Goyette ◽  
Andrew Gatesman
Keyword(s):  
Ocean Surface ◽  
Radar Backscattering

scholarly journals Cross-polarization geophysical model function for C-band radar backscattering from the ocean surface and wind speed retrieval

2015 ◽  
Vol 120 (2) ◽  
pp. 893-909 ◽  
Author(s):  
Paul A. Hwang ◽  
Ad Stoffelen ◽  
Gerd-Jan van Zadelhoff ◽  
William Perrie ◽  
Biao Zhang ◽  
...  
Keyword(s):  
Wind Speed ◽  
Ocean Surface ◽  
Cross Polarization ◽  
Model Function ◽  
Geophysical Model ◽  
Geophysical Model Function ◽  
Radar Backscattering

Global ocean surface stratifications due to rain based on ERA5

2020 ◽  
Author(s):  
Hugo Bellenger ◽  
Xavier Perrot ◽  
Lionel Guez ◽  
Jean-Philippe Duvel ◽  
Alexandre Supply ◽  
...  
Keyword(s):  
Large Scale ◽  
Chemical Species ◽  
Ocean Surface ◽  
Surface Fluxes ◽  
Global Ocean ◽  
Wind Condition ◽  
Solar Absorption ◽  
Temperature Changes ◽  
Global Estimate ◽  
Salinity Anomaly

<p>Temperature and Salinity at the ocean interface can be substantially different than their bulk values in the ocean mixed layer at 5-10 meters depth. The main phenomena that account for these differences are (i) the interfacial millimeter scale diffusive microlayer usually cooler and saltier than below due to surface fluxes and (ii) diurnal warm layers of few tens of centimeters to few meters that form under weak wind condition due to solar absorption. Although characterized by small vertical scales, these tightly wind-related phenomena corresponds to coherent structures up to the large-scale where they can impact air-sea exchanges of heat, water and chemical species. Another phenomenon that can impact global air-sea exchanges is the freshwater lenses produced by rain. Rain freshens and cools the ocean surface, as raindrops temperature is usually lower than surface temperature. The induced negative salinity anomaly enables surface cold anomalies to be sustained and further cooled down by surface fluxes after rain has ceased. This study presents a first global estimate of basic statistics rain-induced ocean surface freshening and temperature changes and of their variations with seasons.</p>

scholarly journals Microwave Specular Measurements and Ocean Surface Wave Properties

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1486
Author(s):  
Paul A. Hwang ◽  
Thomas L. Ainsworth ◽  
Jeffrey D. Ouellette
Keyword(s):  
Surface Wave ◽  
Ocean Surface ◽  
Closed Form Expression ◽  
Wind Condition ◽  
High Wind ◽  
Ocean Surface Waves ◽  
Wind Speeds ◽  
Surface Measurements ◽  
Ocean Surface Wave ◽  
Reference Measurements

Microwave reflectometers provide spectrally integrated information of ocean surface waves several times longer than the incident electromagnetic (EM) wavelengths. For high wind condition, it is necessary to consider the modification of relative permittivity by air in foam and whitecaps produced by wave breaking. This paper describes the application of these considerations to microwave specular returns from the ocean surface. Measurements from Ku and Ka band altimeters and L band reflectometers are used for illustration. The modeling yields a straightforward integration of a closed-form expression connecting the observed specular normalized radar cross section (NRCS) to the surface wave statistical and geometric properties. It remains a challenge to acquire sufficient number of high-wind collocated and simultaneous reference measurements for algorithm development or validation and verification effort. Solutions from accurate forward computation can supplement the sparse high wind databases. Modeled specular NRCSs are provided for L, C, X, Ku, and Ka bands with wind speeds up to 99 m/s.

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