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

The atmospheric dynamics in the Dead Sea Valley has been studied for decades. However, the studies relied mostly on surface observations and simple coarse-model simulations, insufficient to elucidate the complex flow in the area. In this seminar I will present a first study using high resolution (temporal and spatial) and sophisticate both, measurements and modeling tools. We focused on afternoon hours during summer time, when the Mediterranean Sea breeze penetrates into the Dead Sea Valley and sudden changes of wind, temperature and humidity occur in the valley.An intense observations period in the area, including ground-based remote sensing and in-situ observations, took place during August and November 2014. The measurements were conducted as part of the Virtual Institute DEad SEa Research Venue (DESERVE) project using the KITcube profiling instruments (wind lidars, radiometer and soundings) along with surface Energy Balance Station. These observations enabled analysis of the vertical profile of the atmosphere at one single location at the foothills of Masada, about 1 km west of the Dead Sea shore.High resolution (1.1 km grid size) model simulations were conducted using the Advanced Research Weather version of the Weather Forecast and Research mesoscale model (WRF). The simulations enabled analysis of the 3D flow at the Dead Sea Valley, information not provided by the observations at a single location. Sensitivity tests were run to determine the best model configuration for this study.Our study shows that foehn develops in the lee side of the Judean Mountains and Dead Sea Valley in the afternoon hours when the Mediterranean Sea breeze reaches the area. The characteristics of the Mediterranean Sea breeze penetration into the valley and of the foehn (e.g. their depth) and the impact they have on the boundary layer flow in the Dead Sea Valley (e.g. sudden changes in temperature, humidity and wind) are conditioned to the daily synoptic and mesosocale conditions. In the synoptic scale, the depth of the seasonal pressure trough at sea level and the height of inversion layers play a significant role in determining the breeze and foehn characteristics. In the mesoscale, the intensity of the Dead Sea breeze and the humidity brought by it determines the outcomes at the time of Mediterranean Sea breeze penetration and foehn development. Dynamically, the foehn is associated with a hydraulic jump.Hypothetical model simulations with modified terrain and with warmer Mediterranean Sea surface temperature were conducted to reveal the relative contribution of each of these factors and of their synergism on the observed phenomena. The information provided by the factor separation study can be useful in future climate projections, when a warmer Mediterranean Sea is expected.The forecasting feasibility of foehn and the sudden changes in the Dead Sea valley 24 hours in advance using WRF is suggested following the present study. These forecasts can be most valuable for the region affected by pollution penetration from the metropolitan coastal zone.

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Foehn-induced effects on local dust pollution, frontal clouds and solar radiation in the Dead Sea valley

Meteorology and Atmospheric Physics ◽

10.1007/s00703-017-0521-1 ◽

2017 ◽

Vol 130 (3) ◽

pp. 295-309 ◽

Cited By ~ 3

Author(s):

Pavel Kishcha ◽

Boris Starobinets ◽

Amit Savir ◽

Pinhas Alpert ◽

Michael Kaplan

Keyword(s):

Solar Radiation ◽

Dead Sea ◽

Dust Pollution ◽

The Dead ◽

Local Dust

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Observations of Unexpected Short-Term Heating in the Uppermost Layer of the Dead Sea after a Sharp Decrease in Solar Radiation

International Journal of Oceanography ◽

10.1155/2017/5810575 ◽

2017 ◽

Vol 2017 ◽

pp. 1-12 ◽

Cited By ~ 2

Author(s):

Pavel Kishcha ◽

Boris Starobinets ◽

Isaac Gertman ◽

Tal Ozer ◽

Pinhas Alpert

Keyword(s):

Solar Radiation ◽

Temperature Rise ◽

Dead Sea ◽

Hypersaline Lake ◽

Water Heating ◽

Short Term ◽

Sharp Drop ◽

Uppermost Layer ◽

The Dead ◽

Buoy Measurements

The Dead Sea is one of the saltiest bodies of water in the world. Observational evidence has been obtained of unexpected short-term water heating in the 2 m uppermost layer of this hypersaline lake, following a sharp drop in solar radiation under weak winds. This was carried out using Dead Sea buoy measurements. Passing frontal cloudiness mixed with significant dust pollution over the Judean Mountains and the Dead Sea, which occurred on March 22, 2013, led to a dramatic drop in noon solar radiation from 860 W m−2 to 50 W m−2. This drop in solar radiation caused a short-term (1-hour) pronounced temperature rise in the uppermost layer of the sea down to 2 m depth. After the sharp drop in noon solar radiation, in the absence of water mixing, buoy measurements showed that the temperature rise in the uppermost layer of the Dead Sea took place for a shorter time and was more pronounced than the temperature rise under the regular diurnal solar cycle. The water heating could be explained by gravitational instability in the skin-surface layer, when the warm surface water with the increased salinity and density submerged, thereby increasing temperature in the layers below.

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Investigation of sea-breeze/foehn in the Dead Sea valley employing high resolution WRF and observations

Atmospheric Research ◽

10.1016/j.atmosres.2019.06.012 ◽

2019 ◽

Vol 229 ◽

pp. 240-254 ◽

Cited By ~ 5

Author(s):

Pavel Kunin ◽

Pinhas Alpert ◽

Dorita Rostkier-Edelstein

Keyword(s):

High Resolution ◽

Sea Breeze ◽

Dead Sea ◽

The Dead

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Asymmetry in surface temperature between the east and west sides of the Dead Sea under uniform solar radiation

10.5194/egusphere-egu2020-1847 ◽

2020 ◽

Author(s):

Pavel Kishcha ◽

Boris Starobinets ◽

Rachel Pinker ◽

Pavel Kunin ◽

Pinhas Alpert

Keyword(s):

Remote Sensing ◽

Surface Water ◽

Heat Flow ◽

Solar Radiation ◽

Surface Temperature ◽

Dead Sea ◽

Surface Heat ◽

Sea Surface ◽

The West ◽

The Dead

The Dead Sea is a terminal hypersaline lake with a depth of ~300 m, at a unique location approximately 430 m below sea level. Because of very high salinity of ~300 g/kg of Dead Sea water, the non-linear absorption of solar radiation is of an order of magnitude greater than that in fresh-water lakes. Consequently, by contrast to surface water temperature in fresh-water lakes, Dead Sea surface temperature is influenced by wind speed and water mixing. In the absence of vertical water mixing under weak winds, solar radiation in the summer months leads to significant warming of Dead Sea surface water. Under such conditions, daytime sea surface temperature (SST) could reach land surface temperature (LST) over land areas adjacent to the lake. This could lead to an essential reduction of surface heat flow from land to sea and, consequently, significant surface heating of land areas adjacent to the lake.Pronounced asymmetry has been obtained in daytime surface temperature between the east and west sides of the Dead Sea. This asymmetry was observed in the summer months, under uniform solar radiation. Our findings are based on MODIS data (2002&#8211;2016) on board the Terra and Aqua satellites. MODIS data showed that, on average for the 15-year study period, daytime SST over the eastern part of the lake exceeded that over the western part by 5 &#176;C. This SST asymmetry (observed in the absence of surface heat flow from land to sea at the eastern side) was accompanied by the asymmetry in LST over areas adjacent to the Dead Sea. Specifically, LST over areas adjacent to the east side exceeded that over areas adjacent to the west side by 10 &#176;C. Such LST difference is the characteristic feature of the hypersaline Dead Sea. In addition to MODIS records (on board the two orbital satellites - Terra and Aqua), Meteosat Second Generation records (on board the geostationary satellites) proved the presence of daytime SST/LST asymmetry.Regional atmospheric warming led to a decrease in the SST asymmetry during the study period. Temperature difference between daytime SST over the east part and that over the west of the Dead Sea steadily decreased at the rate of 0.32 &#176;C decade-1, based on MODIS/Terra data, and 0.54 &#176;C decade-1, based on MODIS/Aqua data.We found that the Weather Forecast and Research (WRF) model distribution of skin temperature over land and sea does not correspond to satellite observations. At midday, over the sea, WRF was incapable of reproducing the observed SST asymmetry. Over land areas adjacent to both the west and east sides of the lake, WRF incorrectly showed that modeled skin temperature increases with its approach to the coastline. The application to modeling of the observed SST/LST asymmetry in existing regional models will improve simulations of atmospheric dynamics over the Dead Sea.&#160;Reference: &#160;Kishcha P., Starobinets B., Pinker R., Kunin P., Alpert P. (2020). Spatial non-uniformity of surface temperature of the Dead Sea and adjacent land areas. Remote Sensing, Special Issue: Lake Remote Sensing, 12(1), 107; doi:10.3390/rs12010107.

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