Recent measurements of the spectral backward-scattering coefficient in coastal waters

摘要

Abstract: The backward scattering coefficient b$-b$/ was measured in various coastal waters with fixed-angle backscattering sensors developed by the authors. Measurements were made at four discrete wavelengths covering the spectral range 440 to 675 nm. A power law spectral dependence of b$-b$/ due to scattering by particles was investigated of the form b$- b$/$+p$/($lambda@) $EQ b$-b$/$+p$/ ($lambda$-0$/) ($lambda$- 0$//$lambda@)$+$gamma@, where the superscript p denotes particle scattering and $lambda is the wavelength. The exponent $gamma depends on the particle size distribution and composition of particles. Extensive measurements in Monterey Bay, California, showed that 0.1 $LSEQ $gamma $LSEQ 1.1, where the lower values were in the clear, interior waters generally below 10 m. For the upper 10 m, 0.7 $LSEQ $gamma $LSEQ 1.0, and $gamma $CNGR 0.8. In the relatively clear Gulf of Mexico waters near Panama City, Florida, $gamma for the upper 10 m was found to be in the range, 0.9 $LSEQ $gamma $LSEQ 1.1, with $gamma $CNGR 1.0. At dry Tortugas, which consists of clear coral reef water, 0.9 $LSEQ $gamma $LSEQ 1.1, and $gamma $CNGR 1.0. In the thick, green-brown waters of East Sound, Washington, 0 $LSEQ $gamma $LSEQ 0.1, which thus were the most spectrally 'flat' waters measured. !4