Geophysical and hydrological investigations at the west bank of Nile River (Luxor, Egypt)

Luxor, the modern Egyptian city that occupies the site of ancient Thebes, is famed for its magnificent ancient monuments. Since 1967, the Aswan high dam has prevented the annual flooding of the Nile River, resulting in excessive salt accumulation on the Nile floodplains and on exposed monument surfaces. In addition, the expansion of agricultural land within the Luxor study area has resulted in increased salinity and groundwater level. These conditions accelerate the degradation of buried and exposed monuments that were fairly well preserved in the past. To mitigate this problem, it is necessary to first understand the near-surface setting and the groundwater conditions of the Luxor area. A geophysical investigation was carried out using resistivity and electromagnetic surveys. In addition, a chemical analysis was conducted of some surface water samples collected from canals and the sacred lake of Memnon Temple. Based on the results of the geophysical surveys and the chemical analysis of the water samples, the shallow subsurface was characterized into four geoelecterical units. Groundwater flow directions were determined to be from the central area to the west, causing a rise in the groundwater levels and groundwater salinity in the area of monuments.     

Determination of mangrove forest performance in reducing tsunami run-up using physical models

Coastal ecosystems such as mangroves fringing tropical coastlines have been recognized as natural protectors of the coastal areas against destructive attack of a tsunami. In this paper, the authors aim to investigate the interaction of a tsunami wave on a typical mangrove forest and to determine its performance in reducing the run-up. A laboratory experiment using a hydraulic flume with a mangrove forest model was carried out in which tests were conducted by varying the vegetation widths of 0, 1, 2 and 3?m and average densities of 8, 6 and 4 trees per 100?cm² using a scale ratio of 1:100. Two conditions of water levels were considered in the experiments at several tsunami wave heights between 2.4 and 14?cm. The dam break method used in the experiments produced two types of waves. At low water condition, a bore was developed and subsequently, a solitary wave was produced during high water. The results of the experiments showed that in general, vegetation widths and densities demonstrate a dampening effect on tsunami run-up. A larger vegetation width was found to be more effective in dissipating the wave energy. The first 1?m width of mangrove forest could reduce 23?C32?% during high water and 31?C36?% during low water. Increasing the mangrove forest width to 2 and 3?m could further increase the average percentage of run-up reduction by 39?C50?% during high water and 34?C41?% during low water condition. It was also observed that densities of the mangrove forest do not influence the run-up reduction as significantly as the forest widths. For mangrove forest densities to be significantly enough to reduce more tsunami run-up, an additional density of 4 trees/100?m² needs to be provided. The experiments also showed that mangrove roots are more effective in reducing the run-up compared to the trunks and canopies. The experiments managed to compare and present the usefulness of mangrove forests in dissipating wave energy and results produced are beneficial for initiating design guidelines in determining setback limits or buffer zones for development projects in mangrove areas.     

Characteristics of optical emissions and particle precipitation in polar cap arcs

Simultaneous optical and particle data from the ISIS-2 satellite are used to characterize polar cap arcs. Polar cap arcs are identified from two-dimensional geomagnetic transforms of the optical data along with precipitating electron data for the time at which the satellite is on the field line intersecting the arc. No precipitating protons were detected for any of the arc crossings. The pitch angle. distribution of the precipitating electrons is generally isotropic and the differential electron spectra show enhancements in the flux in the 300–750 eV energy range. The average energy of the precipitating electrons for the different arcs ranges from about 300 to 600 eV. A possible explanation of the observed precipitating particle characteristics is that parallel electric fields are accelerating polar rain type spectra at an altitude of several thousand km. For the arc crossings reported here the equivalent 4278 Å emission rate per unit energy deposition rate has a mean value of 162 R/(erg cm^?2 s^?1). Average 3914 Å intensities are about 0.8 kR while 6300 Å intensities range from 0.5 to 3 kR. Model calculations indicate that direct impact excitation is a minor source for the 5577 Å emission rate, but supplies approx. 40% of the 6300 Å emission.     

BIOMONITORING OF AMBIENT CONCENTRATIONS OF CADMIUM, COPPER, I,EAD AND ZINC IN THE COASTAL WETLAND WATER BY USING GILLS OF THE GREEN- LIPPED MUSSEL PERNA VIRIDIS

The distribution and concentrations of Cd, Cu, Pb and Zn were determined in the gills and remaining soft tissues of Perna viridis collected from 12 geographical sites （ 10 from the west and 2 from the east coastal waters） of Peninsular Malaysia. All samples showed that the levels of Cd, Pb and Zn were generally higher in the gill than those in the remaining soft tissues. These results could be due to the fact that gills are the first organ of metal accumulation and larger surface area with mucus sheets in the organ. Since the mussel gill is a better accumulator of Cd, Pb and Zn of ambient seawater than remaining soft tissue, it is a potential indicator of ambient levels of dissolved metals in the ambient seawater. However, further validations based on laboratory conditions are needed.     

An investigation of Malaysian granitic rocks as suitable sources of feldspar

Medium- to coarse-grained leucocratic granitic bodies containing more than 60% feldspar and less than 10% mafic minerals are found to be appropriate and potential source materials of local feldspar. Out of the 72 granite quarries/outcrops studied in Peninsular Malaysia, 31 have been identified as “ideal” sources of feldspar conforming to the “preferred” feldspar specification of >18% Al₂O₃, >11% (Na₂O+K₂O) and <0.3% Fe₂O₃. A feldspar recovery efficiency exceeding 60% was achieved in this study. Despite the positive and encouraging indication that the extracted feldspar samples of different chemical composition are found to be suitable for the general purpose of making ceramic bodies and glaze, the chemical content of the feldspar, nevertheless, could be critical for the manufacture of specific end products. At 1250°C all extracted feldspar samples were fused; however, at the lower temperature of 1170°C feldspar samples extracted from some “Central Belt granites” remained unfused. The Eastern Province granites generally yielded feldspars which show better fusion characteristics i.e. (unblemished) than those extracted from the Main Range Province. A valuable by-product of the feldspar extraction process is silica sand.     

Feature Extraction of Laser Scan Data Based on Geometric Properties

Terrestrial Laser Scanner (TLS) is an important device to provide three-dimensional geometric information with respect to known reference coordinates system. The data from TLS are often called point clouds due to their high density. They are unstructured and do not have any explicit information about the object, except 3D positional and intensity information to each point. Data segmentation and feature extraction are fundamental problems in the point cloud processing step. These are important prerequisites for object recognition and environment understanding. This paper describes a methodology to use the geometrical information of the scanned object, such as a normal vector to extract and segment object edges. The edge based segmentation technique will be studied and improved. The proposed method is programmed and used to extract different region boundaries for two real TLS data, and the quality of the results shows the effectiveness of the proposed algorithm.     

The Thermodynamic Structure of Arctic Coastal Fog Occurring During the Melt Season over East Greenland

An automated method to classify Arctic fog into distinct thermodynamic profiles using historic in-situ surface and upper-air observations is presented. This classification is applied to low-resolution Integrated Global Radiosonde Archive (IGRA) soundings and high-resolution Arctic Summer Cloud Ocean Study (ASCOS) soundings in low- and high-Arctic coastal and pack-ice environments. Results allow investigation of fog macrophysical properties and processes in coastal East Greenland during melt seasons 1980–2012. Integrated with fog observations from three synoptic weather stations, 422 IGRA soundings are classified into six fog thermodynamic types based on surface saturation ratio, type of temperature inversion, fog-top height relative to inversion-base height and stability using the virtual potential temperature gradient. Between 65–80% of fog observations occur with a low-level inversion, and statically neutral or unstable surface layers occur frequently. Thermodynamic classification is sensitive to the assigned dew-point depression threshold, but categorization is robust. Despite differences in the vertical resolution of radiosonde observations, IGRA and ASCOS soundings yield the same six fog classes, with fog-class distribution varying with latitude and environmental conditions. High-Arctic fog frequently resides within an elevated inversion layer, whereas low-Arctic fog is more often restricted to the mixed layer. Using supplementary time-lapse images, ASCOS microwave radiometer retrievals and airmass back-trajectories, we hypothesize that the thermodynamic classes represent different stages of advection fog formation, development, and dissipation, including stratus-base lowering and fog lifting. This automated extraction of thermodynamic boundary-layer and inversion structure can be applied to radiosonde observations worldwide to better evaluate fog conditions that affect transportation and lead to improvements in numerical models.     

Long-range seasonal rainfall forecast for Zimbabwe and its relation with El-Niño/Southern Oscillation (ENSO)

Summary This investigation shows a fairly definite connection between the mean seasonal rainfall in a rainy season and the ground minimum temperature in the preceding two winter seasons in Zimbabwe. The latter is considered to represent the intensity of the over land high over Botswana and the corresponding degree of cooling of the subcontinent during the winter season. This over land high is related to the east-west overturning Walker Circulation. This relationship emphasizes that the rainfall variability over Zimbabwe is strongly linked to the ENSO phenomenon.The study brings out an empirical relationship between these two factors from which the mean seasonal rainfall over Zimbabwe can be predicted three months before the start of the rainy season. These approaches have been examined against independent data covering a period of 20 years and the results were very encouraging.

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Zusammenfassung Diese Untersuchung zeigt einen ziemlich deutlichen Zusammenhang zwischen dem durchschnittlichen Niederschlag während der Regenzeit und den Bodentemperatur-Minima während der beiden vorhergehenden Winter in Zimbabwe. Letztere Daten sollen die Intensität des Land-Hochs über Botswana repräsentieren und somit das Ausmaß der Abkühlung des Subkontinents während des Winters zeigen. Dieses Land-Hoch steht in Zusammenhang mit der auf Ost—West umschlagenden Walker-Zirkulation. Dies macht deutlich, daß zwischen der Niederschlags-Variabilität über Zimbabwe und dem ENSO-Phänomen ein enger Zusammenhang besteht.Die vorliegende Studie weist einen empirischen Zusammenhang zwischen den beiden Faktoren nach, wodurch eine Vorhersage des durchschnittlichen Niederschlags über Zimbabwe bereits drei Monate vor Beginn der Regenzeit möglich wird. Die genannten Ansätze wurden mit einem unabhängigen Datensatz von 20 Jahren überprüft und durch das Ergebnis in ermutigender Weise bestätigt.

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With 7 Figures