Infrared imagery of ocean internal waves

Marmorino, G. O.; Smith, Geoffrey B.; Lindemann, Gloria J.

doi:10.1029/2004gl020152

Cited by 32 publications

(45 citation statements)

References 19 publications

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“…A growing number of airborne studies [10][11][12][13][14][15][16] demonstrated the power of this remote sensing modality to detect and image a wide variety of dynamical processes taking place at or below the air-sea interface. A mid-or long-wave infrared camera is capturing passive radiation emitted by the water no deeper than the skin layer, i.e., tens of microns.…”

Section: Infrared Methodsmentioning

confidence: 99%

Airborne Remote Sensing of the Upper Ocean Turbulence during CASPER-East

et al. 2018

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This study takes on the challenge of resolving upper ocean surface currents with a suite of airborne remote sensing methodologies, simultaneously imaging the ocean surface in visible, infrared, and microwave bands. A series of flights were conducted over an air-sea interaction supersite established 63 km offshore by a large multi-platform CASPER-East experiment. The supersite was equipped with a range of in situ instruments resolving air-sea interface and underwater properties, of which a bottom-mounted acoustic Doppler current profiler was used extensively in this paper for the purposes of airborne current retrieval validation and interpretation. A series of water-tracing dye releases took place in coordination with aircraft overpasses, enabling dye plume velocimetry over 100 m to 10 km spatial scales. Similar scales were resolved by a Multichannel Synthetic Aperture Radar, which resolved a swath of instantaneous surface velocities (wave and current) with 10 m resolution and 5 cm/s accuracy. Details of the skin temperature variability imprinted by the upper ocean turbulence were revealed in 1-14,000 m range of spatial scales by a mid-wave infrared camera. Combined, these methodologies provide a unique insight into the complex spatial structure of the upper ocean turbulence on a previously under-resolved range of spatial scales from meters to kilometers. However, much attention in this paper is dedicated to quantifying and understanding uncertainties and ambiguities associated with these remote sensing methodologies, especially regarding the smallest resolvable turbulent scales and reference depths of retrieved currents.Keywords: airborne remote sensing; ocean surface currents; upper ocean turbulence BackgroundCapabilities for spatial measurements of ocean surface turbulence are highly desirable for a wide variety of needs ranging from basic studies of upper ocean mixing processes to data assimilation into high-resolution coastal and ocean circulation models. On the global scale, presently available observations of the ocean currents are provided by satellite altimeters, which are limited to mesoscales and resolve only the geostrophic component of the surface current. Much anticipated launches of the

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Section: Infrared Methodsmentioning

confidence: 99%

Airborne Remote Sensing of the Upper Ocean Turbulence during CASPER-East

et al. 2018

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“…Similar variability has been observed previously under low-wind conditions and associated with oceanic internal waves (Walsh et al, 1998;Marmorino et al, 2004). However, coincident measurements of the subsurface thermal structure associated with these surface temperature features were lacking; and attribution of the surface signature to a specific mechanism was not conclusive.…”

Section: Resultsmentioning

confidence: 56%

“…If the cool-skin modulation hypothesis of Marmorino et al (2004) was correct, then the internal-wave signal would be expected to exist only in the skin temperature (or at least be significantly different from the internal-wave signal measured in subsurface temperature at 10-20 cm depth). In contrast, if the warm-layer modulation hypothesis of Walsh et al (1998) was correct, then the internal-wave signal in skin temperature would be expected to be essentially the same as the signal observed at 10-20 cm depth (within the warm layer).…”

Section: Resultsmentioning

confidence: 99%

“…However, coincident measurements of the subsurface thermal structure associated with these surface temperature features were lacking; and attribution of the surface signature to a specific mechanism was not conclusive. Walsh et al (1998) hypothesized that the internal-wave SST signals resulted from modulation of vertical mixing at the base of the O(1 m)-thick warm layer that forms under conditions of low winds and strong insolation, whereas Marmorino et al (2004) hypothesized that the SST signal is caused by internal-wave modulation of the cool-skin effect. (The cool skin is an O(1 mm)-thick layer of relatively cool water that exists because of sensible, latent, and longwave-radiative heat loss from the sea surface.…”

Section: Resultsmentioning

confidence: 99%

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Upper Ocean Dynamics and Horizontal Variability in Low Winds

Weller¹

2007

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LONG-TERM GOALSOur long-range scientific objective is to observe and understand the temporal and spatial variability of the upper ocean, to identify the processes that determine that variability, and to examine its predictability. Air-sea interaction is of particular interest, but attention is also paid to the coupling of the sub-thermocline ocean to the mixed layer and to both the open-ocean and littoral regimes. We seek to do this over a wide range of environmental conditions with the intent of improving our understanding of upper ocean dynamics and of the physical processes that determine the vertical and horizontal structure of the upper ocean. OBJECTIVESLittle work has been done to explore air-sea interaction and upper ocean dynamics in very light winds, and few observations are available that describe the mesoscale and smaller scale horizontal variability of the upper ocean in such conditions. The objectives of this work are to observe and understand in low wind conditions: (1) how and why the vertical structure and properties of the surface boundary layer of the ocean (roughly the upper 20 to 50 m) evolve in time, and (2) how and why this evolution varies at horizontal lags of 10s of meters to 10s of kilometers on time scales of minutes to months. To do so we seek to observe and identify: (1) the processes that spatially modulate the vertical structure of the upper ocean (including the depth, salinity, temperature, and velocity of the mixed layer), (2) the processes at work at the base of the mixed layer (such as entrainment), and (3) the air-sea exchanges (fluxes of heat, freshwater, and momentum) that couple the boundary layers on horizontal scales of tens of meters up to 100 km. APPROACHThe CBLAST-LOW (Coupled Boundary Layers Air-Sea Transfers -Low wind) collaborative research program was set up to address the need to better understand and predict the coupled boundary layers in low wind conditions. It combined observations (in situ and remotely sensed) at a site south of Martha's Vineyard, modeling, and simulations. Observational campaigns were carried out in the summers of 2001, 2002, and 2003. The site was selected because winds are often from offshore (from the south to southwest) with very large fetch while at the same time the synoptic variability yields a wide range of summer heating conditions. The air-sea interaction tower (ASIT) of the Martha's Vineyard Coastal Observatory (MVCO) is situated there approximately 4 km south of the island in 19 m of water. The major cooperative field effort, the Intensive Operating Period or IOP, was completed 1

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“…In the field, this work was expanded further by Sutherland (2013) and Sutherland andMelville (2013, 2015a,b) with a stereo IR setup on R/P FLIP. Airborne IR imagery has been used extensively by Marmorino et al (2004Marmorino et al ( , 2005Marmorino et al ( , 2009Marmorino et al ( , 2010Marmorino et al ( , 2015; Smith, 2007 andSavelyev et al (2018) to observe upper ocean turbulence on slightly larger scales ranging from meters to submesoscales.…”

Section: Introductionmentioning

confidence: 99%

Stereo Thermal Marking Velocimetry

Savelyev

Fuchs

2018

Front. Mech. Eng.

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This paper presents a novel approach to measuring and mapping shape and motion of the water surface. The approach combines and borrows from existing techniques, such as stereo imaging shape recognition and tracking, infrared (IR) laser marking and thermography, and particle image velocimetry. The system consists of a high power IR laser beam controlled by a programmable marking head and two IR cameras tracking the thermal pattern projected by the beam onto the water surface. The paper provides detailed description of the setup, discusses the choice of the thermal pattern, and describes the IR image processing algorithm. An example of resolved surface shape and velocity maps is given for an experiment conducted in a laboratory wave tank.

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Infrared imagery of ocean internal waves

Cited by 32 publications

References 19 publications

Airborne Remote Sensing of the Upper Ocean Turbulence during CASPER-East

Airborne Remote Sensing of the Upper Ocean Turbulence during CASPER-East

Upper Ocean Dynamics and Horizontal Variability in Low Winds

Stereo Thermal Marking Velocimetry

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