Wave-Induced Light-Field Fluctuations in the Sea

Snyder, Russell L.; Dera, Jerzy

doi:10.1364/josa.60.001072

Cited by 63 publications

(54 citation statements)

References 3 publications

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“…Field measurements show that the fluctuations of downwelling irradiance E d are at maximum in clear waters, under clear skies, with high sun altitudes, at wavelengths in the blue-green spectral range, and near the surface within the first ten metres (Dera and Gordon, 1968;Snyder and Dera, 1970;Nikolayev and Prokopov, 1977;Dera and Stramski, 1986). The latest radiometric measurements show very intense fluctuations in irradiance (at 532 nm wavelength and at 0.86 m depth) with peaks exceeding the mean irradiance by a factor of 13 (Gernez et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Modeling of wave-induced irradiance variability in the upper ocean mixed layer

Hieronymi

Macke

2012

Ocean Sci.

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Abstract.A Monte Carlo based radiative transfer model has been developed for calculating the availability of solar radiation within the top 100 m of the ocean. The model is optimized for simulations of spatial high resolution downwelling irradiance E d fluctuations that arise from the lensing effect of waves at the water surface. In a first step the accuracy of simulation results has been verified by measurements of the oceanic underwater light field and through intercomparison with an established radiative transfer model. Secondly the potential depth-impact of nonlinear shaped single waves, from capillary to swell waves, is assessed by considering the most favorable conditions for light focusing, i.e. monochromatic light at 490 nm, very clear oceanic water with a low chlorophyll a content of 0.1 mg m −3 and high sun elevation. Finally light fields below irregular wave profiles accounting for realistic sea states were simulated. Our simulation results suggest that under open ocean conditions light flashes with 50 % irradiance enhancements can appear down to 35 m depth, and light variability in the range of ±10 % compared to the mean E d is still possible in 100 m depth.

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Section: Introductionmentioning

confidence: 99%

Modeling of wave-induced irradiance variability in the upper ocean mixed layer

Hieronymi

Macke

2012

Ocean Sci.

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“…Field measurements are, therefore, essential for validation of the theoretical findings, and many studies based on field measurements were also conducted as early as in the 1960s [e.g., Dera and Gordon, 1968]. They were often performed at a single wavelength in the green part of the electromagnetic spectrum, which was imposed by the technology used at that time for the filters, and which also corresponded to the maximum of transparency for the coastal waters under scrutiny [e.g., Dera and Gordon, 1968;Snyder and Dera, 1970;Stramski, 1986;Dera et al, 1993]. More recently, the spectral behavior of the fluctuations in the visible range was analyzed in the clear waters of the Sargasso Sea [Stramska and Dickey, 1998].…”

Section: Introductionmentioning

confidence: 99%

“…Some of the main facts can be listed below. The fluctuations of E d are created by the focusing of sunlight rays refracted by surface gravity and capillary waves [Dera and Gordon, 1968;Schenck, 1957;Snyder and Dera, 1970]. They are maximal under clear skies and within the first ten meters [Dera, 1970], although sometimes observed down to 35 m in clear waters [Stramska and Dickey, 1998].…”

Section: Introductionmentioning

confidence: 99%

Field characterization of wave‐induced underwater light field fluctuations

Gernez¹,

Antoine²

2009

J. Geophys. Res.

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[1] A field characterization of the amplitude and periods of the underwater light field fluctuations is presented on the basis of field measurements of the downward and upward irradiances at a deep-sea mooring in the Mediterranean Sea (BOUSSOLE site). The optical time series at this site includes multispectral irradiance measurements at two depths and irradiance profiles taken from free-fall radiometers. It is already several years long and is paralleled by a time series of wind and waves. When pooled together, both data sets provide an opportunity to complement previous field experiments dedicated to the understanding of underwater light fluctuations, which were mostly carried out in coastal waters and essentially for the downward irradiance, by exploring more systematically the electromagnetic spectrum and the range of environmental parameters. In addition, the characteristics of the upward flux are also investigated. The behavior of the amplitude and period of the

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“…At small depths, the underwater light regime is governed by high-frequency and small-scale intensity changes (e.g. Snyder and Dera, 1970;Hieronymi and Macke, 2010;Darecki et al, 2011). For this reason, we choose a high spatial resolution of dx = 2.5 mm for our nearsurface model; some current irradiance collectors have sensor head diameters of 2.5 mm (e.g.…”

Section: Radiative Transfer Modelsmentioning

confidence: 99%

“…Schenck, 1957;Snyder and Dera, 1970;Nikolayev and Khulapov, 1976;Stramski and Dera, 1988;Gernez et al, 2011). Whereas, less is known about the winddependency of light fluctuations and very little is known about its sea state dependency.…”

Section: Introductionmentioning

confidence: 99%

On the influence of wind and waves on underwater irradiance fluctuations

Hieronymi

Macke

2012

Ocean Sci.

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Abstract. The influence of various wind and wave conditions on the variability of downwelling irradiance E d (490 nm) in water is subject of this study. The work is based on a two-dimensional Monte Carlo radiative transfer model with high spatial resolution. The model assumes conditions that are ideal for wave focusing, thus simulation results reveal the upper limit for light fluctuations. Local wind primarily determines the steepness of capillary-gravity waves which in turn dominate the irradiance variability near the surface. Down to 3 m depth, maximum irradiance peaks that exceed the mean irradiance E d by a factor of more than 7 can be observed at low wind speeds up to 5 m s −1 . The strength of irradiance fluctuations can be even amplified under the influence of higher ultra-gravity waves; thereby peaks can exceed 11 E d . Sea states influence the light field much deeper; gravity waves can cause considerable irradiance variability even at 100 m depth. The simulation results show that under realistic conditions 50 % radiative enhancements compared to the mean can still occur at 30 m depth. At greater depths, the underwater light variability depends on the wave steepness of the characteristic wave of a sea state; steeper waves cause stronger light fluctuations.

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Wave-Induced Light-Field Fluctuations in the Sea

Cited by 63 publications

References 3 publications

Modeling of wave-induced irradiance variability in the upper ocean mixed layer

Modeling of wave-induced irradiance variability in the upper ocean mixed layer

Field characterization of wave‐induced underwater light field fluctuations

On the influence of wind and waves on underwater irradiance fluctuations

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