The relation of reflectance to backscatter and absorption parameters is investigated for waters more turbid than those of previous investigations. Experimental data are examined for river waters in which beam attenuation values range from 8.9 to 18.9 m(_1) at 550 nm. Attenuation, absorption, backscatter, and irradiance reflectance spectral properties are presented for wavelengths between 450 and 800 nm. Comparisons of reflectance with backscatter to absorption ratio and backscatter with absorption plus backscatter ratio indicate that data for turbid waters do not fit linear or polynomial models which are presently available in the literature.

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Results from both field measurements and laboratory simulations are used to assess the effects of dissolved organic materials on turbid-water optical properties. Upwelled reflectance, attenuation, absorption, and b•ckscatter spectral properties at wavelengths from 450 to 800 nm are examined in relation to water chemistry. From these data it is clear that dissolved organic materials decrease upwelled reflectance from turbid waters. Depending on wavelength, the decrease in reflectance is a nonlinear function of concentration with largest gradients at low carbon concentrations. Large increases in absorption coefficient (particu!arly at blue wavelengths) are observed with increases in dissolved organic mate•al. Changes in backscatter coefficient are moderate, indicating mi•mal changes in particle scattering. Upwelled reflectance is highly correlated with two backs½•ttter-absorption parameters used in certain optical models. Both ba•gkscatter-absorption parameters prove to be nonlinear with dissolved organic material concentration change.

Horizontal spectra of temperature fluctuations on wavelengths from the mesoscale to the fine scale and spectra of conductivity fluctuations on the microscale are reported. These spectra are combined with intermediate‐scale isopycnal displacement data of Katz (1973), and a composite potential energy spectrum is constructed which spans scales from 2 cm to 2000 km, a range of eight decades in wave number. The overlap in energy level between scales is remarkably consistent, even though the data were acquired in different oceans and at depths from 60 to 600 m. This composite spectrum can be fit roughly by a −2 power law across these scales, and excesses above this level occur near 500 km, near 1 km, and on scales less than about 15 m. The excesses at the longest and shortest scales are apparent when energetic features, specifically mesoscale eddies and fine‐structure and microstructure patches, occur in the data. Spectral levels vary by an order of magnitude on the mesoscale and by 3 orders of magnitude on the fine scale and microscale. There appears to be a minimum in the relative variability in spectral level in the band from 1 to 50 km.