Interannual variability of Mediterranean evaporation and its relation to regional climate     

Igor I. Zveryaev  Abdel A. Hannachi 《Climate Dynamics》2012,38(3-4):495-512

Gridded monthly evaporation data for 1958–2006 from the Woods Hole Oceanographic Institution data set are used to investigate interannual variability of Mediterranean evaporation during cold and hot seasons and its relation to regional atmospheric dynamics, sea surface temperature and atmospheric elements of the hydrological cycle. The first EOF mode of Mediterranean evaporation, explaining more than 50% of its total variance, is characterized by the monopole pattern both in winter and summer. However, despite structural similarity, the EOF-1 of Mediterranean evaporation is affected by different climate signals in cold and hot seasons. During winter the EOF-1 is associated with the East Atlantic teleconnection pattern. In summer, there is indication of tropical influence on the EOF-1 of Mediterranean evaporation (presumably from Asian monsoon). Both in winter and summer, principal components of EOF-1 demonstrate clear interdecadal signals (with a stronger signature in summer) associated with large sea surface temperature anomalies. The results of a sensitivity analysis suggest that in winter both the meridional wind and the vertical gradient of saturation specific humidity (GSSH) near the sea surface contribute to the interdecadal evaporation signal. In summer, however, it is likely that the signal is more related to GSSH. Our analysis did not reveal significant links between the Mediterranean evaporation and the North Atlantic Oscillation in any season. The EOF-2 of evaporation accounts for 20% (11%) of its total variance in winter (in summer). Both in winter and summer the EOF-2 is characterized by a zonal dipole with opposite variations of evaporation in western and eastern parts of the Mediterranean Sea. This mode is associated presumably with smaller scale (i.e., local) effects of atmospheric dynamics. Seasonality of the leading modes of the Mediterranean evaporation is also clearly seen in the character of their links to atmospheric elements of the regional hydrological cycle. In particular, significant links to precipitation in some regions have been found in winter, but not in summer.  相似文献   

Evaluation of the effect of water management interventions on water level of Gaza coastal aquifer     

Mazen Abualtayef  Ghada Abdel Rahman  Ismael Snounu  Khalid Qahman  Hasan Sirhan  Ahmed Khaled Seif 《Arabian Journal of Geosciences》2017,10(24):555

Gaza coastal aquifer (GCA) is the most precious natural source where it is the only source of water for different uses. Groundwater crisis in Gaza includes two major folds: shortage of water supply and contamination. The extraction of groundwater currently exceeds the aquifer recharge rate. As a result, the groundwater level is falling continuously leading severely deterioration of GCA. The main objective of this study is to analyze and evaluate the current and proposed water resources management plans and their effect on the water level of GCA. In this respect, the available quantities of rainfall that could be harvested and infiltrated from different types of land-use based on existing and planned situations are studied using GIS tool and numerical models for GCA using V-MODFLOW environment for simulating four scenarios: (i) existing management practice (no action scenario), (ii) proposed Palestinian Water Authority (PWA) stormwater infiltration plan, (iii) proposed Gaza Emergency Technical Assistance Program (GETAP) interventions, and (iv) combination between second and third scenarios. The management scenarios were tested with the calibrated flow model for the target period between 2016 and 2040. The simulation results of existing management practice scenario show that there are several depression zones in Gaza Strip; in southern part from ??18 to ??24 m MSL in 2020 and 2040, in the northern part from ??7 to ??12 m MSL in 2020 and 2040, and in the middle regions experienced a small decline in groundwater level. The simulation results of proposed PWA scenario indicate similar depression zones as per first scenario but with good enhancement of water level, ??17 to ??18 m MSL in the southern part and ??3 to ??6 m MSL in the northern part in 2020 and 2040, respectively. The simulation results of GETAP intervention scenario show a positive impact on groundwater level. The results of fourth scenario show good enhancement of water level, in which the water level in the northern part ranges from +?3 to +?6 m MSL in 2020 and 2040, while in the south part ranges from ??15 to +?4 MSL in 2020 and 2040.  相似文献   

Correlation of Aerogravity and BHT Data to Develop a Geothermal Gradient Map of the Northern Western Desert of Egypt using an Artificial Neural Network     

Haby S. Mohamed  Mohamed Abdel Zaher  Mahmoud M. Senosy  Hakim Saibi  Mohamed El Nouby  J. Derek Fairhead 《Pure and Applied Geophysics》2015,172(6):1585-1597

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An Upper Cretaceous (Campanian-Maastrichtian) actinopterygian fish assemblage from the marginal marine Adaffa Formation of Saudi Arabia     

Benjamin P. Kear  Thomas H. Rich  Mohammed A. Ali  Yahya A. Al-Mufarrih  Adel H. Matiri  Abdu M. Al-Masary  Yousry Attia 《Cretaceous Research》2009,30(5):1164-1168

Actinopterygian remains have been recovered from Upper Cretaceous (lower Campanian to lower Maastrichtian) marginal marine deposits of the Adaffa Formation in northwestern Saudi Arabia. The fossils comprise gars (Lepisosteidae), pachycormids (cf. Protosphyraena sp.), indeterminate pycnodontiforms, enchodontid teleosts (cf. Enchodus sp.) and other indeterminate Teleostei. This assemblage is significant because it includes a novel occurrence for the Middle East (Pachycormidae) together with taxa (Lepisosteidae, Pycnodontiformes, Enchodontidae) that have been previously recorded from Late Cretaceous faunas elsewhere in the Mediterranean Tethyan region.  相似文献   

Experimental and Numerical Investigation of the Flow Hydraulic in Gradual Transition Open Channels     

Adel Asnaashari  Amir Ahmad Dehghani  Ali Akbar Akhtari  Hossein Bonakdari 《Water Resources》2018,45(4):565-577

Channel expansions are common in both natural and artificial open channels. With increasing cross-sectional dimensions in an expansion, the flow decelerates. Due to separation of flow and subsequent eddy formation, a significant head loss is occurred along the transition. This study presents the results of experimental investigations on subcritical flow along the expansive transition of rectangular to trapezoidal channels. Also, a numerical simulation was developed using the finite volume method with Reynolds Stress turbulent model. Water surface profiles and velocity distributions of flow through the transition were measured experimentally and compared with the numerical results. Also, hydraulic efficiency of the transition and coefficient of energy head loss were calculated. The results show that with increasing the upstream Froude number, hydraulic efficiency of the transition and coefficient of energy head loss are decreased and increased, respectively. The results also showed the ability of numerical simulation for simulating the flow separation zones and bed shear stress along the transition for different inlet discharges and inflow Froude numbers.  相似文献   

Modelling the impact of a time-varying wave angle on the nonlinear evolution of sand bars in the surf zone     

Abdel Nnafie  Niek van Andel  Huib de Swart 《地球表面变化过程与地形》2020,45(11):2603-2612

Sandy beaches are often characterized by the presence of sand bars, whose characteristics (growth, migration speed, etc.) strongly depend on offshore wave conditions, such as wave height and angle of wave incidence. This study addresses the impact of a sinusoidally time-varying wave angle of incidence with different time-means on the saturation height, migration speed and longshore spacing of sand bars. Model results show that shore-transverse sand bars (so-called TBR bars) eventually develop under a time-varying wave angle. Depending on the time-mean, amplitude and period of the varying angle of wave incidence, the mean heights and mean migration speeds of the bars can be larger or smaller than their corresponding values in the case of time-invariant angles. Bars might not even form when the wave angle varies around a too large oblique mean value, whereas bars exist in the case of a time-invariant wave angle. The oscillations in both bar height and migration speed are large if the period of the time-varying wave angle is close to the adjustment timescale of the system and if large differences in the local growth and migration rates of the bars occur during one oscillation period. The oscillations in bar height are a combination of harmonics with the principal period and half the period of the time-varying wave angle, whereas those of migration speed contain only the principal period. Bars that are subject to time-varying wave angles have larger longshore crest-to-crest spacings than those which form under fixed wave angles. Physical explanations for these findings are given. © 2020 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd  相似文献   

Accurate determination of highly eccentric orbits in earth's gravtational field with axial symmetry     

A. Abdel Aziz Bakry 《Earth, Moon, and Planets》1988,41(1):77-88

In this paper, an algorithm is constructed for the determination of the perturbed motion, in both, the rectangular and the orbital elements of highly eccentric orbits in Earth's gravitational field with axial symmetry whatever the number N of the zonal harmonic coefficients may be. An application of the algorithm for the Explorer 28 satellite (e > 0.94) is given for two geopotential models corresponding to N = 2 and N = 36. In both examples extremely accurate predictions during the satellite life time are obtained.  相似文献   

Third-order Uranus-Neptune theory     

Abdel Aziz Bakry 《Earth, Moon, and Planets》1988,42(1):77-106

In this paper of the third order Uranus-Neptune planetary theory which is the third part of this work for the third order theory, we compute the Poisson brackets in the Lie series which is used to transform canonical variables. We apply Hori-Lie technique in this work and neglect all powers higher than the second in Poincaré variables H, K, P, Q. We restrict this work to the principal part of the disturbing function.  相似文献   

The construction of a seventh-order Jupiter-Saturn analytical theory     

Osman M. Kamel  Adel S. Soliman 《Earth, Moon, and Planets》1993,60(2):141-175

We extend the construction of the Jupiter-Saturn theory to include all the terms up to the seventh order in the masses. The Hori-Lie transformation technique is employed. The Jacobian coordinates are adopted and the theory is expressed in terms of the canonical non-singular variables of H. Poincaré.  相似文献   

Motion of artificial satellites in the set of Eulerian redundant parameters,II     

Mohammed Adel Sharaf  Mervat El-Sayed Awad  Samiha Al-Sayed Abdullah Najmuldeen 《Earth, Moon, and Planets》1991,55(3):223-231

In this paper the full recurrent power series solution is established for J ₂-gravity perturbed motion in terms of the Eulerian redundant parameters. Applications of the method for the problem of the final state prediction are illustrated by numerical examples of some typical ballistic missiles, a final state of very high accuracy is obtained for each case study.  相似文献