NOAA’s Synthetic Aperture Radar Marine User’s Manual
by Christopher Jackson and Benjamin Holt
Beginning with the launch of SEASAT in 1978, SAR satellites have provided a global perspective on a wide range of diverse ocean and atmospheric phenomena. The finely-detailed imagery of the ocean’s surface from SAR is assuredly the most complex and least understood data set that is provided by a remote sensing instrument. What to make of the unprecedented two-dimensional views of waves, currents and eddies, slicks, surface manifestations of subsurface features, brushed over by interactions with the boundary layer, has captivated and perplexed researchers for over three decades. Add to this mix, the ocean’s motion during the SAR imaging process and one has quite a challenge to derive information on what these image patterns uniquely convey about the upper ocean processes and air-sea exchange.
To help people understand the types of information that may be obtained from SAR images of the ocean, the NOAA/NESDIS Office of Research and Applications sponsored the creation of the “Synthetic Aperture Radar (SAR) Marine User’s Manual.” The Manual was conceived by Dr. John Apel as a way to help educate potential users about the capabilities of SAR for ocean remote sensing. It is intended for non-expert, scientifically literate investigators who wish to use SAR data in their studies, but need assistance in understanding the features visible in the imagery.
The Manual is composed of 20 chapters and is divided into four sections (Background, Oceanic Measurements, Atmospheric and Boundary Layer Measurements, and Sea Ice Observations). Each chapter’s authors are recognized experts in their respective fields.
The background material in Section I (Chapters 1 - 3) presents the basic properties of SAR as well as introduces the factors behind how the sea surface and sea ice are observed by microwave radiation and radar in particular. Section II (Chapters 4 - 12) looks at the manifestations of various oceanic processes, including surface waves and spectra, internal waves, currents, upwelling, underwater topography, surfactants, and ship and wake detection. Section III (Chapters 13 - 17) is devoted to atmospheric and boundary layer measurements, including wind speed and direction, cellular convection, roll vortices, mesoscale storms, gravity waves, vortex streets, and rainfall. Section IV (Chapters 18 - 20) examines sea ice, the ice edge, and icebergs.
Where appropriate, information is included on how SAR is being used routinely to aid the operational mission of environmental agencies (Chapters 12, 13, and 20 discuss wind, ship and ice, respectively).
Overall the manual is 464 pages in length and fully indexed. It contains over 240 images and figures, and more than 70 are in color. The Appendices describe the imaging modes and products of the major SAR satellites as well as providing a list of on-line SAR image archives and other resources.
The entire content of the Manual is available on line at www.sarusersmanual.com as a series of individual PDF files. The site also contains a link to purchase a hardcopy from the U.S. Government Printing Office’s on-line bookstore.
(Cost inside the U.S. is $73.00)
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