Can IR Images of the Water Surface Be Used to Quantify the Energy Spectrum and the Turbulent Kinetic Energy Dissipation Rate?

Near-surface oceanic turbulence plays an important role in the exchange of mass, momentum, and energy between the atmosphere and the ocean. The climate modifying the air-sea CO2 transfer rate varies linearly with the surface turbulent kinetic energy dissipation rate to the 1/4 power in a range of systems with different types of forcing, such as coastal oceans, river estuaries, large tidal freshwater rivers, and oceans. In the first part of this paper, we present a numerical study of the near-surface turbulent kinetic energy spectra deduced from a direct numerical simulation (DNS) compared to turbulent kinetic energy spectra deduced from idealized infrared (IR) images.

A Salinity-Temperature Sensor Based on Microwave Resonance Reflection.

We developed and tested a microwave in situ salinity sensor (MiSSo) to simultaneously measure salinity and temperature within the same water sample over broad ranges of salinity (S) (3−50 psu) and temperature (T) (3−30 °C). Modern aquatic S sensors rely on measurements of conductivity (C) between a set of electrodes contained within a small volume of water. To determine water salt content or S, conductivity, or C, measurements must be augmented with concurrent T measurements from the same water volume.

Polarimetric lidar measurements of aquatic turbulence-laboratory experiment: erratum.

We present an erratum to inform readers about the location of the data for our paper.

Polarimetric lidar measurements of aquatic turbulence - laboratory experiment.

Lidar is one of few remote sensing methods available to researchers to sense below the oceanic air-surface. We present polarimetric lidar measurements of turbulence in a laboratory generated turbulent flow. We found that the nearforward light depolarization characterized by the depolarization rate γ(z), varies with the turbulent flow parameter: χ(z)∊(z), where χ(z) and ∊(z) are the respective depth dependent, temperature variance, and turbulent kinetic energy dissipation rates.

Laboratory measurements of light beam depolarization on turbulent convective flow.

Laboratory measurements of light beam depolarization by a turbulent flow, corresponding to oceanic turbulence within the oceanic mixed layer, show that the depolarization rate (1x10(-5)?m(-1) to 3x10(-3)?m(-1)) correlates with turbulence strength and is consistent with polarized lidar observations [Opt. Express, 16, 1196 (2008)OPEXFF1094-408710.1364/OE.

Numerical study of light scattering by a boundary-layer flow.

Temperature inhomogeneities in free, isotropic turbulence have the effect of scattering light in near-forward angles. We investigate numerically modifications of free turbulence by a rigid wall and its effect on the propagation of light through turbulence. The wall is a 5 cm optical window placed at the leading edge of an instrument towed with speeds of 0.

Light scattering on oceanic turbulence.

Turbulent inhomogeneities of fluid flow have the effect of scattering light in near-forward angles, thus providing an opportunity to use optics to quantify turbulence. Here we report measurements of the volume-scattering function in the range of 10(-7) to 10(-3) rad using a wave-front sensing technique. The total scattering coefficient b, due to scattering on turbulent inhomogeneities, is between 1 and 10 m(-1) under typical oceanographic conditions.