Estimation of wave and wind fields from spaceborne SAR imagery in the Mediterranean Sea

2004 ◽  
Author(s):  
Giacomo De Carolis
Keyword(s):  
Mediterranean Sea ◽  
Wind Fields ◽  
The Mediterranean ◽  
Sar Imagery

scholarly journals Improved near real time surface wind resolution over the Mediterranean Sea

Ocean Science ◽  
2007 ◽  
Vol 3 (2) ◽  
pp. 259-271 ◽  
Author(s):  
A. Bentamy ◽  
H.-L. Ayina ◽  
P. Queffeulou ◽  
D. Croize-Fillon ◽  
V. Kerbaol
Keyword(s):  
Wind Speed ◽  
Mediterranean Sea ◽  
Real Time ◽  
Surface Wind ◽  
Surface Wind Speed ◽  
Remotely Sensed ◽  
Wind Fields ◽  
Remotely Sensed Data ◽  
Space And Time ◽  
The Mediterranean

Abstract. Several scientific programs, including the Mediterranean Forecasting System Toward Environmental Predictions (MFSTEP project), request high space and time resolutions of surface wind speed and direction. The purpose of this paper is to focus on surface wind improvements over the global Mediterranean Sea, based on the blending near real time remotely sensed wind observations and ECMWF wind analysis. Ocean surface wind observations are retrieved from QuikSCAT scatterometer and from SSM/I radiometers available at near real time at Météo-France. Using synchronous satellite data, the number of remotely sensed data available for each analysis epoch (00:00 h; 06:00 h; 12:00 h; 18:00 h) is not uniformly distributed as a function of space and time. On average two satellite wind observations are available for each analysis time period. The analysis is performed by optimum interpolation (OI) based on the kriging approach. The needed covariance matrixes are estimated from the satellite wind speed, zonal and meridional component observations. The quality of the 6-hourly resulting blended wind fields on 0.25° grid are investigated trough comparisons with the remotely sensed observations as well as with moored buoy wind averaged wind estimates. The blended wind data and remotely wind observations, occurring within 3 h and 0.25° from the analysis estimates, compare well over the global basin as well as over the sub-basins. The correlation coefficients exceed 0.95 while the rms difference values are less than 0.30 m/s. Using measurements from moored buoys, the high-resolution wind fields are found to have similar accuracy as satellite wind retrievals. Blended wind estimates exhibit better comparisons with buoy moored in open sea than near shore.

scholarly journals The InflateSAR Campaign: Evaluating SAR Identification Capabilities of Distressed Refugee Boats

2020 ◽  
Vol 12 (21) ◽  
pp. 3516
Author(s):  
Peter Lanz ◽  
Armando Marino ◽  
Thomas Brinkhoff ◽  
Frank Köster ◽  
Matthias Möller
Keyword(s):  
Mediterranean Sea ◽  
Incidence Angle ◽  
Test Site ◽  
Detection Algorithm ◽  
Open Ocean ◽  
The Mediterranean ◽  
Sar Imagery ◽  
Low Incidence ◽  
The Moment ◽  
Metallic Parts

Most of the recent research in the field of marine target detection has been concentrating on ships with large metallic parts. The focus of this work is on much more challenging targets represented by small rubber inflatables. They are of importance, since in recent years they have largely been used by migrants to cross the Mediterranean Sea between Libya and Europe. The motivation of this research is to mitigate the ongoing humanitarian crisis at Europe’s southern borders. These boats, packed with up to 200 people, are in no way suitable to cross the Mediterranean Sea or any other big water body and are in distress from the moment of departure. The establishment of a satellite-based surveillance infrastructure could considerably support search and rescue missions in the Mediterranean Sea, reduce the number of such boats being missed and mitigate the ongoing death in the open ocean. In this work we describe and analyze data from the InflateSAR acquisition campaign, wherein we gathered multiple-platform SAR imagery of an original refugee inflatable. The test site for this campaign is a lake which provides background clutter that is more predictable. The analysis considered a sum of experiments, enabling investigations of a broad range of scene settings, such as the vessel’s orientation, superstructures and speed. We assess their impact on the detectability of the chosen target under different sensor parameters, such as polarimetry, resolution and incidence angle. Results show that TerraSAR-X Spotlight and Stripmap modes offer good capabilities to potentially detect those types of boats in distress. Low incidence angles and cross-polarization decrease the chance of a successful identification, whereas a fully occupied inflatable, orthogonally oriented to the line of sight, seems to be better visible than an empty one. The polarimetric analyses prove the vessel’s different polarimetric behavior in comparison with the water surface, especially when it comes to entropy. The analysis considered state-of-the-art methodologies with single polarization and dual polarization channels. Finally, different metrics are used to discuss whether and to which extent the results are applicable to other open ocean datasets. This paper does not introduce any vessel detection or classification algorithm from SAR images. Rather, its results aim at paving the way to the design and the development of a specially tailored detection algorithm for small rubber inflatables.

scholarly journals Improved near real time surface wind resolution over the Mediterranean Sea

2006 ◽  
Vol 3 (3) ◽  
pp. 435-470 ◽  
Author(s):  
A. Bentamy ◽  
H.-L. Ayina ◽  
P. Queffeulou ◽  
D. Croize-Fillon
Keyword(s):  
Wind Speed ◽  
Mediterranean Sea ◽  
Real Time ◽  
Surface Wind ◽  
Surface Wind Speed ◽  
Remotely Sensed ◽  
Wind Fields ◽  
Remotely Sensed Data ◽  
Space And Time ◽  
The Mediterranean

Abstract. Several scientific programs, including the Mediterranean Forecasting System Toward Environmental Predictions (MFSTEP project), request high space and time resolutions of surface wind speed and direction. The purpose of this paper is to focus on surface wind improvements over the global Mediterranean Sea, based on the blending near real time remotely sensed wind observations and ECMWF wind analysis. Ocean surface wind observations are retrieved from QuikSCAT scatterometer and from SSM/I radiometers available at near real time at Météo-France. Using synchronous satellite data, the number of remotely sensed data available for each analysis epoch (00:00 h; 06:00 h; 12:00 h; 18:00 h) is not uniformly distributed as a function of space and time. On average two satellite wind observations are available for each analysis time period. The analysis is performed by optimum interpolation (OI) based on the kriging approach. The needed covariance matrixes are estimated from the satellite wind speed, zonal and meridional component observations. The quality of the 6-hourly resulting blended wind fields on 0.25° grid are investigated trough comparisons with the remotely sensed observations as well as with moored buoy wind averaged wind estimates. The blended wind data and remotely wind observations, occurring within 3 h and 0.25° from the analysis estimates, compare well over the global basin as well as over the sub-basins. The correlation coefficients exceed 0.95 while the rms difference values are less than 0.30 m/s. Using measurements from moored buoys, the high-resolution wind fields are found to have similar accuracy as satellite wind retrievals. Blended wind estimates exhibit better comparisons with buoy moored in open sea than near shore.

Aeromonas dhakensis pneumonia and sepsis in a neonate Risso’s dolphin Grampus griseus from the Mediterranean Sea

2015 ◽  
Vol 116 (1) ◽  
pp. 69-74 ◽  
Author(s):  
L Pérez ◽  
ML Abarca ◽  
F Latif-Eugenín ◽  
R Beaz-Hidalgo ◽  
MJ Figueras ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Grampus Griseus ◽  
The Mediterranean ◽  
Risso's Dolphin

Dolphin Morbillivirus in the Mediterranean Sea

2008 ◽  
Vol 34 (4) ◽  
pp. 514-515 ◽  
Author(s):  
Giovanni Di Guardo
Keyword(s):  
Mediterranean Sea ◽  
Dolphin Morbillivirus ◽  
The Mediterranean
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