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Optical properties of the Dead Sea
Author(s) -
Boss Emmanuel,
Gildor Hezi,
Slade Wayne,
Sokoletsky Leonid,
Oren Aharon,
Loftin James
Publication year - 2013
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
eISSN - 2169-9291
pISSN - 2169-9275
DOI - 10.1002/jgrc.20109
Subject(s) - salinity , absorption (acoustics) , biogeochemistry , particulates , spectral slope , attenuation , mineralogy , absorption spectroscopy , geology , environmental science , chemistry , environmental chemistry , spectral line , oceanography , materials science , optics , physics , organic chemistry , astronomy , composite material
The Dead Sea, located in the rift valley between Jordan and Israel, is a hypersaline lake, resulting in unique biogeochemistry and optical properties. In the spring of 2004 we conducted two days of physical and optical measurements in the lake. Because of the significant effect of dissolved salts on the optical properties of water, our analysis required a novel processing approach to obtain dissolved and total inherent optical properties from the measurements. In addition, we show that the lake's salinity can be estimated from measurements of hyper‐spectral absorption or attenuation spectra in the red and infrared parts of the spectrum, using published values of specific absorption of dissolved NaCl, despite the fact that the lake's salt chemistry is complex. In situ observations demonstrated that the lake has a two‐layer structure with a warm and more turbid layer at the top 20–30 m and a clearer colder layer below. Both the particulate and dissolved absorption are well approximated by exponentially decreasing functions with the spectral slope of the particulate absorption about half that of the dissolved fraction and consistent with other aquatic environments. Both have relatively low and similar magnitudes in the blue (O(0.15 m –1 )). Mean particle size was observed to increase with depth, consistent with precipitating salt crystals (observed in past campaigns) shown here to play a major role in the lake's optical properties.