On the Discrimination of Radar Signatures of Atmospheric Gravity Waves and Oceanic Internal Waves on Synthetic Aperture Radar Images of the Sea Surface

2011 ◽  
Vol 49 (3) ◽  
pp. 1114-1126 ◽  
Author(s):  
Werner Alpers ◽  
Weigen Huang
Keyword(s):  
Synthetic Aperture Radar ◽  
Internal Waves ◽  
Gravity Waves ◽  
Sea Surface ◽  
Synthetic Aperture ◽  
Atmospheric Gravity Waves ◽  
Radar Images ◽  
Radar Signatures ◽  
Atmospheric Gravity ◽  
Aperture Radar

Coexistence of Atmospheric Gravity Waves and Boundary Layer Rolls Observed by SAR*

2013 ◽  
Vol 70 (11) ◽  
pp. 3448-3459 ◽  
Author(s):  
Xiaofeng Li ◽  
Weizhong Zheng ◽  
Xiaofeng Yang ◽  
Jun A. Zhang ◽  
William G. Pichel ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Synthetic Aperture Radar ◽  
Gravity Waves ◽  
Dynamic Instability ◽  
Model Simulation ◽  
The Yellow Sea ◽  
Synthetic Aperture ◽  
Atmospheric Gravity Waves ◽  
Atmospheric Gravity ◽  
Aperture Radar

Abstract Both atmospheric gravity waves (AGW) and marine atmospheric boundary layer (MABL) rolls are simultaneously observed on an Environmental Satellite (Envisat) advanced synthetic aperture radar (ASAR) image acquired along the China coast on 22 May 2005. The synthetic aperture radar (SAR) image covers about 400 km × 400 km of a coastal area of the Yellow Sea. The sea surface imprints of AGW show the patterns of both a transverse wave along the coastal plain and a diverging wave in the lee of Mount Laoshan (1133-m peak), which indicate that terrain forcing affects the formation of AGW. The AGW have a wavelength of 8–10 km and extend about 100 km offshore. Model simulation shows that these waves have an amplitude over 3 km. Finer-scale (~2 km) brushlike roughness features perpendicular to the coast are also observed, and they are interpreted as MABL rolls. The FFT analysis shows that the roll wavelengths vary spatially. The two-way interactive, triply nested grid (9–3–1 km) Weather Research and Forecasting Model (WRF) simulation reproduces AGW-generated wind perturbations that are in phase at all levels, reaching up to the 700-hPa level for the diverging AGW and the 900-hPa level for the transverse AGW. The WRF simulation also reveals that dynamic instability, rather than thermodynamic instability, is the cause for the MABL roll generation. Differences in atmospheric inflection-point level and instability at different locations are reasons why the roll wavelengths vary spatially.

scholarly journals Linear Dispersion Relation and Depth Sensitivity to Swell Parameters: Application to Synthetic Aperture Radar Imaging and Bathymetry

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Valentina Boccia ◽  
Alfredo Renga ◽  
Giancarlo Rufino ◽  
Marco D’Errico ◽  
Antonio Moccia ◽  
...  
Keyword(s):  
Synthetic Aperture Radar ◽  
Gravity Waves ◽  
Sea Surface ◽  
Synthetic Aperture ◽  
Linear Dispersion ◽  
Budget Model ◽  
Linear Dispersion Relation ◽  
Waves Propagation ◽  
Depth Sensitivity ◽  
Aperture Radar

Long gravity waves or swell dominating the sea surface is known to be very useful to estimate seabed morphology in coastal areas. The paper reviews the main phenomena related to swell waves propagation that allow seabed morphology to be sensed. The linear dispersion is analysed and an error budget model is developed to assess the achievable depth accuracy when Synthetic Aperture Radar (SAR) data are used. The relevant issues and potentials of swell-based bathymetry by SAR are identified and discussed. This technique is of particular interest for characteristic regions of the Mediterranean Sea, such as in gulfs and relatively close areas, where traditional SAR-based bathymetric techniques, relying on strong tidal currents, are of limited practical utility.

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