Thermal Infrared Multipath Reflection from Breaking Waves Observed at Large Incidence Angles

Branch, Ruth; Chickadel, C. Chris; Jessup, Andrew T.

doi:10.1109/tgrs.2013.2238241

Cited by 4 publications

(6 citation statements)

References 22 publications

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“…Recent work with IR imagers operating in the mid-and longwave spectral regions has revealed a complex signature of residual foam due to breaking waves. Although limited data are available, they show that the foam IR brightness temperature of actively breaking waves is higher than a quiescent water surface at the same physical temperature [23,24]. Furthermore, this increase in brightness temperature is due to a one to three percent increase in the emissivity for typical oblique viewing angles [13,25].…”

Section: Introductionmentioning

confidence: 99%

Laboratory Heat Flux Estimates of Seawater Foam for Low Wind Speeds

et al. 2022

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Laboratory experiments were conducted to measure the heat flux from seafoam continuously generated in natural seawater. Using a control volume technique, heat flux was calculated from foam and foam-free surfaces as a function of ambient humidity (ranged from 40% to 78%), air–water temperature difference (ranged from −9 °C to 0 °C), and wind speed (variable up to 3 m s−1). Water-surface skin temperature was imaged with a calibrated thermal infrared camera, and near-surface temperature profiles in the air, water, and foam were recorded. Net heat flux from foam surfaces increased with increasing wind speed and was shown to be up to four times greater than a foam-free surface. The fraction of the total heat flux due to the latent heat flux was observed for foam to be 0.75, with this value being relatively constant with wind speed. In contrast, for a foam-free surface the fraction of the total heat flux due to the latent heat flux decreased at higher wind speeds. Temperature profiles through foam are linear and have larger gradients, which increased with wind speed, while foam free surfaces show the expected logarithmic profile and show no variation with temperature. The radiometric surface temperatures show that foam is cooler and more variable than a foam-free surface, and bubble-resolving thermal images show that radiometrically transparent bubble caps and burst bubbles reveal warm foam below the cool surface layer, contributing to the enhanced variability.

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Section: Introductionmentioning

confidence: 99%

Laboratory Heat Flux Estimates of Seawater Foam for Low Wind Speeds

et al. 2022

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“…This effect has been shown by Niclos et al [2007] to hold whether the sea surface is considered a diffuse or specular reflector. Newer data have extended this relationship to 858 incidence angle [Branch et al, 2012], and the resulting emissivity curves were found in agreement with those from Niclos et al [2007]. The higher emissivity of foam causes foam produced by an actively breaking wave to have a higher apparent temperature than the undisturbed sea surface.…”

Section: Thermal Signal Of the Sea Surfacementioning

confidence: 55%

Estimating wave energy dissipation in the surf zone using thermal infrared imagery

et al. 2015

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Thermal infrared (IR) imagery is used to quantify the high spatial and temporal variability of dissipation due to wave breaking in the surf zone. The foam produced in an actively breaking crest, or wave roller, has a distinct signature in IR imagery. A retrieval algorithm is developed to detect breaking waves and extract wave roller length using measurements taken during the Surf Zone Optics 2010 experiment at Duck, NC. The remotely derived roller length and an in situ estimate of wave slope are used to estimate dissipation due to wave breaking by means of the wave-resolving model by Duncan (1981). The wave energy dissipation rate estimates show a pattern of increased breaking during low tide over a sand bar, consistent with in situ turbulent kinetic energy dissipation rate estimates from fixed and drifting instruments over the bar. When integrated over the surf zone width, these dissipation rate estimates account for 40-69% of the incoming wave energy flux. The Duncan (1981) estimates agree with those from a dissipation parameterization by Janssen and Battjes (2007), a wave energy dissipation model commonly applied within nearshore circulation models.

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“…In this study, the emphasis is on remotely sensed SST as a prerequisite parameter to estimating accurate ocean/sea subsurface water temperature. In the remote sensing approaches used to determine SST, water emissivity is an important constant in the SST equation [103]. When there is a slight spatial change in thermal inertia and the structure of the water, the emissivity is equal both vertically and horizontally, and is assumed to be 1 or near 1.…”

Section: Accurate Sea Surface Temperaturementioning

confidence: 99%

A Review of Ocean/Sea Subsurface Water Temperature Studies from Remote Sensing and Non-Remote Sensing Methods

Akbari

Alavipanah

Jeihouni

et al. 2017

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Oceans/Seas are important components of Earth that are affected by global warming and climate change. Recent studies have indicated that the deeper oceans are responsible for climate variability by changing the Earth's ecosystem; therefore, assessing them has become more important. Remote sensing can provide sea surface data at high spatial/temporal resolution and with large spatial coverage, which allows for remarkable discoveries in the ocean sciences. The deep layers of the ocean/sea, however, cannot be directly detected by satellite remote sensors. Therefore, researchers have examined the relationships between salinity, height, and temperature of the oceans/Seas to estimate their subsurface water temperature using dynamical models and model-based data assimilation (numerical based and statistical) approaches, which simulate these parameters by employing remotely sensed data and in situ measurements. Due to the requirements of comprehensive perception and the importance of global warming in decision making and scientific studies, this review provides comprehensive information on the methods that are used to estimate ocean/sea subsurface water temperature from remotely and non-remotely sensed data. To clarify the subsurface processes, the challenges, limitations, and perspectives of the existing methods are also investigated.

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Thermal Infrared Multipath Reflection from Breaking Waves Observed at Large Incidence Angles

Cited by 4 publications

References 22 publications

Laboratory Heat Flux Estimates of Seawater Foam for Low Wind Speeds

Laboratory Heat Flux Estimates of Seawater Foam for Low Wind Speeds

Estimating wave energy dissipation in the surf zone using thermal infrared imagery

A Review of Ocean/Sea Subsurface Water Temperature Studies from Remote Sensing and Non-Remote Sensing Methods

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