On the influence of wind and waves on underwater irradiance fluctuations.

Hieronymi, Martin and Macke, Andreas (2012) On the influence of wind and waves on underwater irradiance fluctuations. Open Access Ocean Science, 8 (4). pp. 455-471. DOI 10.5194/os-8-455-2012.

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Abstract

The influence of various wind and wave conditions on the variability of downwelling irradiance Ed (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 Ed 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 Ed. 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.

Document Type: Article
Additional Information: WOS:000309616400005
Keywords: Marine meteorology; downwelling irradiance Ed (490 nm); SUBSURFACE CHLOROPHYLL MAXIMUM; SURFACE-WAVES; LIGHT-FIELD; OCEAN WAVES; SEA-SURFACE; DOWNWELLING IRRADIANCE; VERTICAL PROFILES; PACIFIC-OCEAN; VARIABILITY; SPECTRA
Research affiliation: OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-ME Maritime Meteorology
HZG
Refereed: Yes
Open Access Journal?: Yes
DOI etc.: 10.5194/os-8-455-2012
ISSN: 1812-0784
Related URLs:
Date Deposited: 24 Jul 2012 09:07
Last Modified: 25 Jul 2019 10:46
URI: http://oceanrep.geomar.de/id/eprint/14896

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