Imaging of ocean waves by synthetic aperture radar: a comparison of results from Seasat and SIR-B experiments in the North Atlantic

1989 ◽  
Vol 27 (5) ◽  
pp. 568-575 ◽  
Author(s):  
R.A. Cordey ◽  
J.T. Macklin
Author(s):  
Jose´ Carlos Nieto Borge ◽  
Tobias Schneiderhan ◽  
Johannes Schulz-Stellenfleth ◽  
Andreas Niedermeier

The scientific developments carried out in the last years with spaceborne synthetic aperture radar (SAR), as well as the comparisons with in-situ sensors, have demonstrated that SAR is a reliable remote sensing tool to study wave fields on the open ocean. In their so-called SAR image mode, SAR systems on board satellites are able to scan ocean areas about 100 × 100 km2 with a spatial resolution about 20 × 20 m2. These SAR images are able to provide information about the spatial variability of wave fields, as well as other phenomena that occur on the ocean surface, such as the local wind field. This work investigates the capabilities of spaceborne SAR to extract sea state information for those areas close to coastal locations, where the incoming wave fields present high spatial inhomogeneities. For this purpose, ERS-2 SAR and ENVISAT Advanced SAR (ASAR) images acquired over the North Sea and the Bay of Biscay are used to study ocean waves in shallow waters under different climate and oceanographic conditions. In addition, the potential of ENVISAT ASAR capability to scan the ocean surface with dual polarizations (horizontal, HH, and vertical, VV) is analyzed in this work. The relevance of these investigations for different practical applications concerning the analysis of ocean waves is discussed.


2011 ◽  
Vol 268-270 ◽  
pp. 1934-1939
Author(s):  
Kun Chao Lei ◽  
Hui Li Gong ◽  
Xiao Juan Li ◽  
Bei Bei Chen ◽  
Ji Wei Li ◽  
...  

Land subsidence in Cangzhou of the North China Plain, has been an ongoing problem for the past four decades (since the later 1970s). With the development of new synthetic aperture radar(SAR)sensors and interferometric synthetic aperture radar(InSAR) techniques, the application of satellite Radar data have enhanced capabilities to detect and monitor ground displacements with centimeter to millimeter precision at greater spatial detail and higher temporal resolution. We use Permanent Scatterers interferometric synthetic aperture radar(PS-InSAR)technology (Hooper, A.2004) to detect and measure ground movement in this area(from2004 to 2007). Results of the cangzhou region study are reported and the utility of the InSAR methodology is discussed.


1980 ◽  
Vol 85 (C9) ◽  
pp. 5003 ◽  
Author(s):  
William McLeish ◽  
Duncan Ross ◽  
Robert A. Shuchman ◽  
Paul G. Teleki ◽  
S. Vincent Hsiao ◽  
...  

2020 ◽  
Vol 5 (1) ◽  
pp. 375-390 ◽  
Author(s):  
Charlotte B. Hasager ◽  
Andrea N. Hahmann ◽  
Tobias Ahsbahs ◽  
Ioanna Karagali ◽  
Tija Sile ◽  
...  

Abstract. Europe's offshore wind resource mapping is part of the New European Wind Atlas (NEWA) international consortium effort. This study presents the results of analysis of synthetic aperture radar (SAR) ocean wind maps based on Envisat and Sentinel-1 with a brief description of the wind retrieval process and Advanced Scatterometer (ASCAT) ocean wind maps. The wind statistics at 10 and 100 m above mean sea level (a.m.s.l.) height using an extrapolation procedure involving simulated long-term stability over oceans are presented for both SAR and ASCAT. Furthermore, the Weather Research and Forecasting (WRF) offshore wind atlas of NEWA is presented. This has 3 km grid spacing with data every 30 min for 30 years from 1989 to 2018, while ASCAT has 12.5 km and SAR has 2 km grid spacing. Offshore mean wind speed maps at 100 m a.m.s.l. height from ASCAT, SAR, WRF and ERA5 at a European scale are compared. A case study on offshore winds near Crete compares SAR and WRF for flow from the north, west and all directions. The paper highlights the ability of the WRF model to simulate the overall European wind climatology and the near-coastal winds constrained by the resolution of the coastal topography in the WRF model simulations.


2005 ◽  
Vol 45 (1) ◽  
pp. 311 ◽  
Author(s):  
A.T. Jones ◽  
G.A. Logan ◽  
J.M. Kennard ◽  
N. Rollet

The Timor Sea region of the North West Shelf is one of natural hydrocarbon accumulation and seepage, which has been investigated by integrated remote sensing studies in the past 10 years. One of the primary tools incorporated in these studies has been Synthetic Aperture Radar (SAR). During a recent Geoscience Australia marine survey to the Yampi Shelf area, active hydrocarbon seepage was directly observed in the form of gas plumes rising from the sea-floor. Active seepage was not observed in areas associated with dense clusters of elongated to irregularshaped features in the SAR data, which have previously been interpreted as natural hydrocarbon seepage slicks. These slicks, and another dense cluster of slicks across the Browse–Bonaparte Basin Transition Zone, are reassessed in the context of alternative formational processes.Mapping of bathymetric channels directly beneath the SAR slicks using multi-beam swath bathymetry and measurement of tidal currents using an acoustic doppler current profiler indicates that tidal current flows may have contributed to slick formation over the Yampi Shelf headland. In contrast, coral spawning may have contributed to the formation of annular to crescent-shaped SAR slicks associated with submerged reefs and shoals over the nearby transition zone. Subsequent to identifying potential alternative origins for these two types of SAR features, the remaining slicks across the area were re-categorised on the basis of their size and shape in the context of ancillary hydrographic and environmental data. An alternative nonseepage origin was established for most of the 381 SAR slicks previously identified as being related to natural hydrocarbon seepage. This may necessitate a significant downgrading of the extent and frequency of active hydrocarbon (particularly oil) seepage in the region.


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