Fine-scale features on the sea surface in SAR satellite imagery – Part 2: Numerical modeling
With the advent of the new generation of synthetic aperture radar (SAR) satellites, it has become possible to resolve fine-scale features on the sea surface on the scale of meters. The proper identification of sea surface signatures in SAR imagery can be challenging, since some features may be due t...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2014-06-01
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| Series: | Ocean Science |
| Online Access: | http://www.ocean-sci.net/10/427/2014/os-10-427-2014.pdf |
| Summary: | With the advent of the new generation of synthetic aperture radar (SAR) satellites, it has become
possible to resolve fine-scale features on the sea surface on the scale of
meters. The proper identification of sea surface signatures in SAR imagery
can be challenging, since some features may be due to atmospheric distortions
(gravity waves, squall lines) or anthropogenic influences (slicks), and may
not be related to dynamic processes in the upper ocean. In order to improve
our understanding of the nature of fine-scale features on the sea surface and
their signature in SAR, we have conducted high-resolution numerical
simulations combining a three-dimensional non-hydrostatic computational fluid
dynamics model with a radar imaging model. The surface velocity field from
the hydrodynamic model is used as input to the radar imaging model. The
combined approach reproduces the sea surface signatures in SAR of ship wakes,
low-density plumes, and internal waves in a stratified environment. The
numerical results are consistent with observations reported in a companion
paper on in situ measurements during SAR satellite overpasses. Ocean surface and
internal waves are also known to produce a measurable signal in the ocean
magnetic field. This paper explores the use of computational fluid dynamics
to investigate the magnetic signatures of oceanic processes. This potentially
provides a link between SAR signatures of transient ocean dynamics and
magnetic field fluctuations in the ocean. We suggest that combining SAR
imagery with data from ocean magnetometers may be useful as an additional
maritime sensing method. The new approach presented in this work can be
extended to other dynamic processes in the upper ocean, including fronts and
eddies, and can be a valuable tool for the interpretation of SAR images of
the ocean surface. |
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| ISSN: | 1812-0784 1812-0792 |