The Seasonal Variations in Length of Some Marine Planktonic Copepods From the Eastern Mediterranean At Alexandria

Crustaceana ◽  
1965 ◽  
Vol 8 (1) ◽  
pp. 37-47 ◽  
Author(s):  
A.M. El-Maghraby
Keyword(s):  
Seasonal Variations ◽  
Eastern Mediterranean ◽  
Planktonic Copepods

scholarly journals Sources and variability of non-methane hydrocarbons in the Eastern Mediterranean

2013 ◽  
Vol 11 (3) ◽  
pp. 333-340
Keyword(s):  
Natural Gas ◽  
Seasonal Variations ◽  
Eastern Mediterranean ◽  
Lower Troposphere ◽  
Rural Site ◽  
Background Concentration ◽  
Biogenic Origin ◽  
Mixing Ratios ◽  
Stationary Sources ◽  
Biogenic Source

The volume mixing ratios of non-methane hydrocarbons including saturated, unsaturated and aromatic ones (C2 to C8 as non methane hydrocarbons, NMHCS) were measured at three distinct sites (natural, rural, urban) in the lower troposphere of the Eastern Mediterranean from February 2006 to March 2007. Average concentrations for most of the NMHC show clear seasonal variations along the year mainly attributed to photochemistry. Significant correlations found among various hydrocarbons indicate contribution from mobile and stationary sources (exhaust and combustion). Leakages from natural gas (NG) or liquefied petroleum gas (LPG) probably from the continental platforms may account for important sources for the background concentration of ethane and propane in the area. Isoprene has been found to have mostly a biogenic source but its dual anthropogenic–biogenic origin was also evident at the rural site.

scholarly journals Dust Dry Deposition over Israel

Atmosphere ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 197 ◽  
Author(s):  
Pavel Kishcha ◽  
Evgeni Volpov ◽  
Boris Starobinets ◽  
Pinhas Alpert ◽  
Slobodan Nickovic
Keyword(s):  
East Africa ◽  
Seasonal Variations ◽  
Dry Deposition ◽  
Eastern Mediterranean ◽  
Temporal Distribution ◽  
Atmospheric Model ◽  
Dust Deposition ◽  
North East ◽  
Mediterranean Cyclones ◽  
Spatio Temporal

Similar quasiperiodic year-to-year variations of dust dry deposition (DDD) with a two–three-year period were found over Israel and north-east Africa. This phenomenon of quasiperiodic interannual variations of DDD has not been discussed in previous publications. Moreover, similar seasonal variations of DDD were found over both Israel and north-east Africa, characterized by significant dust deposition in spring and a decrease in DDD from spring to autumn. These findings indicate the existence of the same causal factors for interannual and seasonal variations of DDD over the two regions, such as similar surface winds created by Mediterranean cyclones. Daily runs of the Dust REgional Atmospheric Model (DREAM) at Tel Aviv University from 2006 to 2019 were used to investigate the main features of the spatio-temporal distribution of dust dry deposition in the eastern Mediterranean, with a focus on Israel. DREAM showed that, on average, during the 14-year study period, in the winter, spring, and summer months, the spatial distribution of monthly-accumulated DDD over Israel was non-uniform with the maximum of DDD over southern Israel. In the autumn months, DREAM showed an increase in DDD over northern Israel, resulting in an almost uniform DDD pattern. The knowledge of DDD spatio-temporal distribution is helpful for understanding the negative effects of DDD on the performance of solar panels and on insulator flashover in the Israel power electric network.

Modelling the water mass circulation in the Aegean Sea. Part I: wind stresses, thermal and haline fluxes

1994 ◽  
Vol 12 (8) ◽  
pp. 794-807 ◽  
Author(s):  
I. A. Valioulis ◽  
Y. N. Krestenitis
Keyword(s):  
Experimental Evidence ◽  
Black Sea ◽  
Computer Model ◽  
Seasonal Variations ◽  
Water Mass ◽  
Eastern Mediterranean ◽  
Aegean Sea ◽  
Water Fluxes ◽  
Physical Processes ◽  
Mass Circulation

Abstract. The aim of this work is to develop a computer model capable of simulating the water mass circulation in the Aegean Sea. There is historical, phenomenological and recent experimental evidence of important hydrographical features whose causes have been variably identified as the highly complex bathymetry, the extreme seasonal variations in temperature, the considerable fresh water fluxes, and the large gradients in salinity or temperature across neighbouring water masses (Black Sea and Eastern Mediterranean). In the approach taken here, physical processes are introduced into the model one by one. This method reveals the parameters responsible for permanent and seasonal features of the Aegean Sea circulation. In the first part of the work reported herein, wind-induced circulation appears to be seasonally invariant. This yearly pattern is overcome by the inclusion of baroclinicity in the model in the form of surface thermohaline fluxes. The model shows an intricate pattern of sub-basin gyres and locally strong currents, permanent or seasonal, in accord with the experimental evidence.

Air-Sea seasonal CO2 fluxes in a fast warming oligotrophic region – the Eastern Mediterranean case study

2020 ◽  
Author(s):  
Juntao Yu
Keyword(s):  
Mediterranean Sea ◽  
Surface Waters ◽  
Seasonal Variations ◽  
Eastern Mediterranean ◽  
Open Water ◽  
Sea Surface ◽  
Total Alkalinity ◽  
Eastern Region ◽  
Underlying Assumption ◽  
The Mediterranean

<p>In a recent study, it was suggested based on the apparent correlation between multi-annual measurements of summertime maxima and wintertime minima temperature and calculated pCO<sub>2</sub> in the most eastern region of the Mediterranean Sea surface waters that they are a net source of atmospheric CO<sub>2</sub>. Furthermore, it was predicted that the magnitude of this source would increase substantially in this region and that adjacent regions in the Eastern Mediterranean as well would turn into net sources of atmospheric CO<sub>2</sub> due to the fast warming of these waters. In order to confirm the underlying assumption that seasonal variations in pCO<sub>2</sub> in Eastern Mediterranean surface waters are primarily a strong function of seasonal variations in temperature, water samples were collected for the analysis of total alkalinity and pH during 12 monthly cruises from February 2018 to January 2019 at the shallow (THEMO1) and the deep (THEMO2) open water stations that are ca.10 and 20 NM off the Mediterranean coast of Israel. The data from all the cruises show that surface (< 30m depth) seawater pCO<sub>2</sub> has a strong positive linear relationship with temperature in both stations (n=56, r<sup>2</sup>=0.94, p<0.001). The calculated annual net flux of CO<sub>2</sub> from the surface to the atmosphere based on these measurements is ca.1.13 Tg C y<sup>−1</sup>, which is ca.15% higher than the previously estimated flux, but within its range of uncertainty (± 30%). These results clearly demonstrate that surface water pCO<sub>2</sub> levels are indeed a strong positive function of the seasonal variations in sea-surface temperature and that the open water of the most eastern Mediterranean Sea is a net source of atmospheric CO<sub>2</sub>. These results are also in agreement with the conclusions of observational and modelling studies of air-sea CO<sub>2</sub> fluxes in the centers of subtropical gyres and therefore globally relevant.</p>

Seasonal variations in AADSAS applicants

1985 ◽  
Vol 49 (6) ◽  
pp. 445-447
Author(s):  
E Solomon ◽  
D Stoll
Keyword(s):  
Seasonal Variations
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