scholarly journals Dead Sea evaporation by eddy covariance measurements vs. aerodynamic, energy budget, Priestley–Taylor, and Penman estimates

2018 ◽  
Vol 22 (2) ◽  
pp. 1135-1155 ◽  
Author(s):  
Jutta Metzger ◽  
Manuela Nied ◽  
Ulrich Corsmeier ◽  
Jörg Kleffmann ◽  
Christoph Kottmeier
Keyword(s):  
Energy Budget ◽  
Water Budget ◽  
Heat Storage ◽  
Sea Water ◽  
Correlation Coefficients ◽  
Dead Sea ◽  
Eddy Covariance Measurements ◽  
Lake Evaporation ◽  
The Dead ◽  
Storage Term

Abstract. The Dead Sea is a terminal lake, located in an arid environment. Evaporation is the key component of the Dead Sea water budget and accounts for the main loss of water. So far, lake evaporation has been determined by indirect methods only and not measured directly. Consequently, the governing factors of evaporation are unknown. For the first time, long-term eddy covariance measurements were performed at the western Dead Sea shore for a period of 1 year by implementing a new concept for onshore lake evaporation measurements. To account for lake evaporation during offshore wind conditions, a robust and reliable multiple regression model was developed using the identified governing factors wind velocity and water vapour pressure deficit. An overall regression coefficient of 0.8 is achieved. The measurements show that the diurnal evaporation cycle is governed by three local wind systems: a lake breeze during daytime, strong downslope winds in the evening, and strong northerly along-valley flows during the night. After sunset, the strong winds cause half-hourly evaporation rates which are up to 100 % higher than during daytime. The median daily evaporation is 4.3 mm d−1 in July and 1.1 mm d−1 in December. The annual evaporation of the water surface at the measurement location was 994±88 mm a−1 from March 2014 until March 2015. Furthermore, the performance of indirect evaporation approaches was tested and compared to the measurements. The aerodynamic approach is applicable for sub-daily and multi-day calculations and attains correlation coefficients between 0.85 and 0.99. For the application of the Bowen ratio energy budget method and the Priestley–Taylor method, measurements of the heat storage term are inevitable on timescales up to 1 month. Otherwise strong seasonal biases occur. The Penman equation was adapted to calculate realistic evaporation, by using an empirically gained linear function for the heat storage term, achieving correlation coefficients between 0.92 and 0.97. In summary, this study introduces a new approach to measure lake evaporation with a station located at the shoreline, which is also transferable to other lakes. It provides the first directly measured Dead Sea evaporation rates as well as applicable methods for evaporation calculation. The first one enables us to further close the Dead Sea water budget, and the latter one enables us to facilitate water management in the region.

scholarly journals Dead Sea evaporation by eddy covariance measurements versus aerodynamic, energy budget, Priestley–Taylor, and Penman estimates

2017 ◽  
Author(s):  
Jutta Metzger ◽  
Manuela Nied ◽  
Ulrich Corsmeier ◽  
Jörg Kleffmann ◽  
Christoph Kottmeier
Keyword(s):  
Linear Function ◽  
Heat Storage ◽  
Sea Water ◽  
Correlation Coefficients ◽  
Vapour Pressure Deficit ◽  
Dead Sea ◽  
Eddy Covariance Measurements ◽  
The Dead ◽  
Daily Evaporation ◽  
Storage Term

Abstract. The Dead Sea water budget is no longer in equilibrium. The lake level decline exceeds 1 m a−1 and causes severe environmental problems, such as a shifting of the fresh/saline groundwater interface and climatic changes. As the Dead Sea is a terminal lake, located in an arid environment, evaporation is the key component of the Dead Sea water budget and accounts for the main loss of water. However, the actual amount of evaporation as well as the governing factors are unknown. Therefore, for the first time, long-term eddy covariance measurements were performed for a period of one year, starting in March 2014. The total annual amount measured at this location was 994 ± 81 mm a−1. The median daily evaporation rate reaches 4.3 mm d−1 in July and only 1.1 mm d−1 in December. The wind velocity and vapour pressure deficit were identified as the main governing factors of evaporation throughout the year. Consequently, the local wind systems define the diurnal evaporation cycle. In the evening, strong downslope winds govern the wind field and cause evaporation amounts which are up to 100 % higher than during daytime, and also during the night evaporation rates are accelerated compared to daytime evaporation, due to strong northerly along-valley flows. Furthermore, a robust and reliable regression model is presented to calculate sub-daily and multiday evaporation values with a linear function of wind velocity and vapour pressure deficit. An overall correlation coefficient of 0.8 is achieved and the cross validation results in a prediction error of 4.8 %. Finally, indirect evaporation approaches were tested for their applicability for the Dead Sea and compared to the measurements. The aerodynamic approach is applicable for sub-daily and multi-day calculations and attains correlation coefficients between 0.85 and 0.99. For the application of the Bowen-Ratio-Energy-Balance (BREB) method and the Priestley–Taylor method, measurements of the heat storage term are inevitable to calculate evaporation on time scales up to one month. Without the heat storage term, the equations yield strong seasonal biases and over- or underestimate daily evaporation rates by up 100 %. The usage of an empirically gained linear function or a hysteresis model depending on the net radiation to estimate the heat storage term was not accurate enough to provide reliable evaporation amounts. The Penman equation was adapted to calculate realistic evaporation amounts, by using an empirically gained linear function for the heat storage term. The correlation coefficients are above 0.9, the daily mean difference is only 0.5 mm d−1 and the estimated annual amount is within the range of the measurement uncertainties. In summary, this study provides the first directly measured amounts of Dead Sea evaporation and applicable methods to calculate evaporation.

Dead Sea Water Levels Analysis Using Artificial Neural Networks and Firefly Algorithm

2022 ◽  
pp. 1118-1129
Author(s):  
Nawaf N. Hamadneh
Keyword(s):  
Neural Network ◽  
Neural Networks ◽  
Water Level ◽  
Firefly Algorithm ◽  
Sea Water ◽  
Dead Sea ◽  
Water Levels ◽  
Artificial Neural ◽  
The Dead ◽  
Predicted Values

In this study, the performance of adaptive multilayer perceptron neural network (MLPNN) for predicting the Dead Sea water level is discussed. Firefly Algorithm (FFA), as an optimization algorithm is used for training the neural networks. To propose the MLPNN-FFA model, Dead Sea water levels over the period 1810–2005 are applied to train MLPNN. Statistical tests evaluate the accuracy of the hybrid MLPNN-FFA model. The predicted values of the proposed model were compared with the results obtained by another method. The results reveal that the artificial neural network (ANN) models exhibit high accuracy and reliability for the prediction of the Dead Sea water levels. The results also reveal that the Dead Sea water level would be around -450 until 2050.

Gypsum saturation degrees and precipitation potentials from Dead Sea - seawater mixtures

2009 ◽  
Vol 6 (5) ◽  
pp. 416 ◽  
Author(s):  
Itay J. Reznik ◽  
Jiwchar Ganor ◽  
Assaf Gal ◽  
Ittai Gavrieli
Keyword(s):  
Surface Water ◽  
Water Level ◽  
Water Column ◽  
Sea Water ◽  
Theoretical Calculations ◽  
Dead Sea ◽  
Gypsum Precipitation ◽  
The Dead ◽  
Rate Of Decline ◽  
The 1960S

Environmental context. Since the 1960s the Dead Sea water level has dropped by nearly 30 m and over the last decade the rate of decline accelerated to over 1 m per year. Conveying seawater to the Dead Sea to stabilise or even raise its water level is currently being considered but may result in ‘whitening’ of the surface water through the formation of minute gypsum crystals that will remain suspended in the water column for a prolonged period of time. This paper is a first step in attaining the relevant physical and chemical parameters required to assess the potential for such whitening of the Dead Sea. Abstract. Introduction of seawater to the Dead Sea (DS) to stabilise its level raises paramount environmental questions. A major concern is that massive nucleation and growth of minute gypsum crystals will occur as a result of mixing between the SO42–-rich Red Sea (RS) water and Ca2+-rich DS brine. If the gypsum will not settle quickly to the bottom it may influence the general appearance of the DS by ‘whitening’ the surface water. Experimental observations and theoretical calculations of degrees of saturation with respect to gypsum (DSG) and gypsum precipitation potentials (PPT) were found to agree well, over the large range but overall high ionic strength of DS–RS mixtures. The dependency of both DSG and PPT on temperature was examined as well. Based on our thermodynamic insights, slow discharge of seawater to the DS will result in a relatively saline upper water column which will lead to enhanced gypsum precipitation.

scholarly journals Controls on the Radiocarbon Reservoir Ages in the Modern Dead Sea Drainage System and in the Last Glacial Lake Lisan

Radiocarbon ◽  
2007 ◽  
Vol 49 (2) ◽  
pp. 969-982 ◽  
Author(s):  
Reuven Belmaker ◽  
Mordechai Stein ◽  
Yoseph Yechieli ◽  
Boaz Lazar
Keyword(s):  
Mass Balance ◽  
Sea Water ◽  
Dissolved Inorganic Carbon ◽  
Dead Sea ◽  
Glacial Lake ◽  
Chemical Compositions ◽  
Exchange Reactions ◽  
Last Glacial ◽  
The Dead ◽  
The Last Glacial

Carbon isotopic and chemical compositions of freshwaters feeding the Dead Sea and the Sea of Galilee (i.e. perennial streams and floods along their stream profiles) were used to constrain the factors that dictate the reservoir ages (RA) of these lakes and the last glacial Lake Lisan. Runoff waters are characterized by high Ca2+, Mg2+, alkalinity, and radiocarbon contents (67–108 pMC), suggesting a major role for 14C atmospheric exchange reactions (carbonate rock dissolution alone will result in lower pMC values). These exchange processes were corroborated by dissolved inorganic carbon (DIC) and δ13C trends throughout the flood profile. During the evolution from rain to incipient runoff, the 14CDIC of the water increases and is accompanied by a DIC increase and δ13CDIC decrease, suggesting an addition of soil CO2, which is characterized by light δ13C and high 14C content. When incipient runoffs evolve to floods, the opposite trends are observed.It appears that the Sea of Galilee, the Dead Sea, and its last glacial precursor, Lake Lisan, maintained uniform but specific RAs of 0.8 ± 0.1, 2.3 ± 0.1, and 1.6 ± 0.3 kyr, respectively. However, applying the 14C contents of modern Dead Sea water sources to the water mass balance of Lake Lisan reveals that the RA of Lake Lisan is higher than that predicted by the mass balance. This discrepancy may reflect enhanced dissolution of carbonatic dust, changes in the amount of 14C exchanged in Judean Desert floods, or variations in the contribution of brine and saline springs. Furthermore, the small fluctuations in the Lisan RA (1.6 ± 0.3 kyr) may reflect small, short-term changes in the relative contributions of these sources.

scholarly journals Haloplanus natans gen. nov., sp. nov., an extremely halophilic, gas-vacuolate archaeon isolated from Dead Sea–Red Sea water mixtures in experimental outdoor ponds

2007 ◽  
Vol 57 (4) ◽  
pp. 780-783 ◽  
Author(s):  
Rahel Elevi Bardavid ◽  
Lily Mana ◽  
Aharon Oren
Keyword(s):  
Red Sea ◽  
Sea Water ◽  
Halophilic Archaea ◽  
Dead Sea ◽  
Rrna Gene ◽  
16S Rrna Gene Sequences ◽  
Haloferax Mediterranei ◽  
Biological Phenomena ◽  
Experimental Mesocosms ◽  
The Dead

To study biological phenomena in the Dead Sea and to simulate the effects of mixing Dead Sea water with Red Sea water, experimental mesocosms were operated at the Dead Sea Works at Sedom, Israel. Dense communities of red halophilic archaea developed in mesocosms filled with 80 % Dead Sea water and 20 % Red Sea water after enrichment with phosphate. The most common type of colonies isolated from these brines belonged to the genus Halorubrum. A few white–pinkish opaque colonies contained pleomorphic flat cells with gas vesicles. Three strains isolated from the latter colonies were characterized in depth. Their 16S rRNA gene sequences showed only 91 % similarity to the closest cultured relative (Haloferax mediterranei), indicating that the new strains represent a novel species of a new genus. The name Haloplanus natans gen. nov., sp. nov. is proposed for this novel organism. The type strain of Haloplanus natans is RE-101T (=DSM 17983T=JCM 14081T).

scholarly journals Modelling chemistry over the Dead Sea: bromine and ozone chemistry

2009 ◽  
Vol 9 (1) ◽  
pp. 4525-4565 ◽  
Author(s):  
L. Smoydzin ◽  
R. von Glasow
Keyword(s):  
Gas Phase ◽  
Sea Water ◽  
Dead Sea ◽  
Chemical Mechanism ◽  
Polar Regions ◽  
Model Calculations ◽  
Halogen Compounds ◽  
Reactive Halogen Species ◽  
The Dead ◽  
Halogen Species

Abstract. Measurements of O3 and BrO concentrations over the Dead Sea indicate that Ozone Depletion Events (ODEs), widely known to happen in polar regions, are also likely to occur over the Dead Sea due to the very high bromine content of the Dead Sea water. However, we show that BrO and O3 levels as they are detected cannot solely be explained by high Br− levels in the Dead Sea water and the release of gas phase halogen species out of sea borne aerosol particles and their conversion to reactive halogen species. It is likely that other sources for reactive halogen compounds are needed to explain the observed concentrations for BrO and O3. To explain the chemical mechanism taking place over the Dead Sea leading to BrO levels of several pmol/mol we used the single column model MISTRA which calculates microphysics, meteorology, gas and aerosol phase chemistry. We performed pseudo Lagrangian studies by letting the model column first move over the desert which surrounds the Dead Sea region and then let it move over the Dead Sea itself. To include an additional source for gas phase halogen compounds, gas exchange between the Dead Sea water and the atmosphere is treated explicitly. Model calculations indicate that this process has to be included to explain the measurements.

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