Satellite observations of turbidity in the Dead Sea

Abstract

[1] A methodology to attain daily variability of turbidity in the Dead Sea by means of remote sensing was developed. 250 m/pixel moderate resolution imaging spectroradiometer (MODIS) surface reflectance data were used to characterize the seasonal cycle of turbidity and plume spreading generated by flood events in the lake. Fifteen minutes interval images from meteosat second generation 1.6 km/pixel high-resolution visible (HRV) channel were used to monitor daily variations of turbidity. The HRV reflectance was normalized throughout the day to correct for the changing geometry and then calibrated against available MODIS surface reflectance. Finally, hourly averaged reflectance maps are presented for summer and winter. The results show that turbidity is concentrated along the silty shores of the lake and the southern embayments, with a gradual decrease of turbidity values from the shoreline toward the center of the lake. This pattern is most pronounced following the nighttime hours of intense winds. A few hours after winds calm the concentric turbidity pattern fades. In situ and remote sensing observations show a clear relation between wind intensity, wave amplitude and water turbidity. In summer and winter similar concentric turbidity patterns are observed but with a much narrower structure in winter. A simple Lagrangain trajectory model suggests that the combined effects of horizontal transport and vertical mixing of suspended particles leads to more effective mixing in winter. The dynamics of suspended matter contributions from winter desert floods are also presented in terms of hourly turbidity maps showing the spreading of the plumes and their decay.

Increased frequency of torrential rainstorms during a regional late Holocene eastern Mediterranean drought

“…However, debris flow formation might be accompanied by flash floods restricted to the path of the fifth- and sixth-order streams (Ben David-Novak et al, 2004). Sediment loads of flash floods reaching the Dead Sea in these streams are deposited in front of their deltas, while the fine fraction is carried farther into the lake as sediment plumes (Nehorai et al, 2013), which do not affect the DSEn site.…”

Interpreting Soft Sediment Deformation and Mass Transport Deposits as Seismites in the Dead Sea Depocenter

“…Modern offshore sedimentation monitoring in the Dead Sea by satellite observations (Nehorai et al, ) reveals that flash floods play a key role in supplying suspension particles to the deepwater environment. Closer to the shore, the plume generated by the flood floats above the underlying denser brine (density: 1.24 g/cm 3 ) forming a hypopycnal flow.…”

“…Observations in the Dead Sea reveal that typical amplitudes of winter storm waves are less than 2 m (Nehorai et al, 2013;Sirkes et al, 1997). Lake Lisan's lowest water level is much higher than the present Dead Sea (Torfstein et al, 2013).…”

Diurnal Course of Evaporation From the Dead Sea in Summer: A Distinct Double Peak Induced by Solar Radiation and Night Sea Breeze

“…The station is equipped with a data logger (CR1000, Campbell Scientific, USA) and meteorological sensors similar to those on the shore station: A 2‐D Sonic Anemometer, air temperature and relative humidity sensor, both located at 4.5 m above the water surface. Net radiometer (Kipp & Zonen CNR4), installed at ∼1.5 m above the lake water surface at the edge of a ∼2.5 m long horizontal arm (see also Nehorai et al, ). We added an automatic daily washing system to wash sea spray and salt precipitants off the 4 domes on the net radiometer.…”