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1.
The rapid growth of Riyadh—capital of Saudi Arabia—is pushing the area to more pollution and incentive for reorganization. The aim of this research is to assess air pollutants in southeast of Riyadh and detect opinion of the population about their environment. The assessment was done by analyzing 405 questionnaires, evaluating thermal band of Landsat 8, and spatial analyzing of particular matter and chemicals in 19 air samples by geostatistical tool in the ArcMap. Most of the inhabitants stated that they are suffering from bad odor, sewage leakage, and dust mainly from a cement factory. The thermal band of Landsat clarified the location of the pollution sources mainly the 1st industrial city, Yammama Cement Factory, and power plant in Farouq area. The ordinary kriging maps showed that the highest concentration of PM10 (>403 μg/m3) lied to the northern and western side of the study area and caused a health issue to most inhabitants.  相似文献   
2.
Siliyin spring is one of the many natural fresh water springs in the Western Desert of Egypt. It is located at the central part of El-Fayoum Delta, which is a potential place for urban developments and touristic activities. Integrated geoelectrical survey was conducted to facilitate mapping the groundwater resources and the shallow subsurface structures in the area. Twenty-eight transient electromagnetic (TEM) soundings, three vertical electrical soundings (VES) and three electrical resistivity tomography (ERT) profiles were carried out around the Siliyin spring location. The dense cultivation, the rugged topography and the existence of infra structure in the area hindered acquiring more data. The TEM data were inverted jointly with the VES and ERT, and constrained by available geological information. Based on the inversion results, a set of geoelectrical cross-sections have been constructed. The shallow sand to sandy clay layer that forms the shallow aquifer has been completely mapped underneath and around the spring area. Flowing of water from the Siliyin spring is interconnected with the lateral lithological changes from clay to sand soil. Exploration of the extension of Siliyin spring zone is recommended. The interpretation emphasizes the importance of integrating the geoelectrical survey with the available geological information to obtain useful, cheap and fast lithological and structural subsurface information.  相似文献   
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4.
This study uses the seismic refraction and noise measurements to investigate the velocity structure of the subsurface and emphasize the advantage of ambient vibration over the conventional seismic refraction technique. Field measurements were carried out at nine sites in and around Zagazig city. Shallow seismic refraction data were interpreted using the delay time method to obtain the two-dimension ground model at each site. Ambient vibration arrays are used to infer the one-dimensional compressional and shear wave velocity profiles through two main steps. The first step is to derive the dispersion curve from the recorded signals using the frequency-wavenumber method. The second is to invert the dispersion curve to obtain the site velocity profiles. The results of the compressional wave velocities obtained from seismic refraction technique showed that the subsurface consists of a number of layers ranging from two to four layers and give a good agreement with the results of the seismic wave velocities obtained from the ambient vibration arrays. The ambient vibration arrays gave a deeper depth of penetration than the other method, providing more information on the subsurface structure without any disturbance to the environment. This work provides reliable estimates of the seismic velocity structures of both shallow and deep sedimentary layers within the area of interest.  相似文献   
5.
The time fractional KdV equation is derived for small but finite amplitude electron-acoustic solitary waves in plasma of cold electron fluid with two different temperature isothermal ions. The effects of the time fractional parameter on the electrostatic solitary structures are presented. It is shown that the effect of time fractional parameter can be used to modify the amplitude of the electrostatic waves (viz. the amplitude, width and electric field) of the electron-acoustic solitary waves. The model may provide a possible explanation for the low-frequency component of the broadband electrostatic noise in the plasma sheet boundary layer of the Earth’s magnetotail where the electron beams are not present.  相似文献   
6.
An accurate tropical cyclone track and intensity forecast is very important for disaster management. Specialized numerical prediction models have been recently used to provide high-resolution temporal and special forecasts. Hurricane Weather Research and Forecast (HWRF) model is one of the emerging numerical models for tropical cyclone forecasting. This study evaluates the performance of HWRF model during the post monsoon tropical cyclone Nilofar on the north Indian Ocean basin. The evaluation uses the best track data provided by the Indian Meteorological Department (IMD) and the Joint Typhoon Warning Centre (JTWC). Cyclone track, central pressure, and wind speed are covered on this evaluation. Generally, HWRF was able to predict the Nilofar track with track error less than 230 km within the first 66 h of forecast time span. HWRF predicted more intense tropical cyclone. It predicted the lowest central pressure to be 922 hPa while it reached 950 hPa according to IMD and 937 hPa according to JTWC. Wind forecast was better as it predicted maximum wind speed of 122 kt while it reached 110 and 115 kt according to IMD and JTWC, respectively.  相似文献   
7.
To understand the impact of the influence of treated wastewater, a study was undertaken in the downstream side of Wadi Hanifa in the southern part of Riyadh City in Saudi Arabia. Chemical elements from 17 groundwater samples, 9 surface water samples (treated wastewater), and 14 soil samples were analyzed. Water facies analyses showed that both groundwater and surface water belong to the SO4-Cl class. However, the groundwater is characterized by high salinity (average value of 3547 mg/l), which may be result of the greater rock-water interaction and limited rainfall recharge. The NO3 values are also high in the groundwater samples (average value of 40 mg/l) and are mainly attributed to the agricultural practices in the study area. The surface water samples (treated wastewater from the plant) shows an average salinity value of 1232 mg/l and is better suited for irrigation purposes. Heavy elements analyzed in the soil samples show high concentrations of all the elements except Mn and Ni as compared to their background concentration. Enrichment factor and index of geoaccumulation calculated from the soil samples indicate that they are severely enriched with respect to Cd and Se. The spatial distribution maps were prepared based on kriging interpolation technique to estimate the concentrations of the analyzed elements at unknown locations. The treated wastewater in the study area is better suited for agricultural and domestic activities as compared to groundwater.  相似文献   
8.
This study examines riparian vegetation cover changes along ephemeral channels due to the emplacement of the Central Arizona Project (CAP) canal. Two research questions examined are the following: (1) How has riparian vegetation changed over the course of twenty-eight years due to altered flow conditions? (2) How has channel morphology affected changes in vegetation cover? Five Landsat TM images acquired in 1982, 1989, 1996, 2003, and 2010 were classified. The average change of vegetation cover per 0.5-km section over the twenty-eight-year period is approximately 100,436 m2 over 25.5-km length of the canal on the upstream section. In addition, the total amount of vegetation cover increase in the twenty-eight years over the 25.5-km length of the canal is approximately 5,122,239 m2. Larger streams experienced a greater increase in vegetation cover upslope than smaller streams. In addition, streams of similar width dimensions that were completely closed off resulted in greater vegetation cover than streams that were semiconnected. A significant relationship between changes in vegetation green-up and channel widths was examined. Results from this study suggest that there is a quasi-linear relationship between channel widths and increases in vegetation cover for altered and impounded channels due to the presence of the CAP canal.  相似文献   
9.
Ground penetrating radar, electromagnetic terrain conductivity, and electric tomography have proven to be effective tools if they are combined together to investigate archeological sites. We have conducted a geophysical survey at the Akhmim archaeological site, the main objective of our survey is to locate additional buried structures for further excavation. Geophysical data were acquired in the area using the GEM-300 multi-frequency terrain conductivity profiler, the SIR 2000 ground penetrating radar, and the Syscal R2 resistivity meter systems. The results of the integrated interpretation show a number of buried features and a strong linear zone about 1 m wide that coincides with the suspected trend of a buried wall. There appears to be two parallel ridges of strong reflections on either side, indicating two parallel walls extended East-West and a room is identified at the bottom left comer of the site. Moreover, the interpretation results of some selected GPR and dipoledipole resistivity profiles adjacent to the open-air museum suggest the existence of a second statue of Ramses Ⅱ to the right of the previously discovered statue which could still be buried in the sand.  相似文献   
10.
The Africa–Arabia plate boundary comprises the Red Sea oceanic spreading centre and the left‐lateral Dead Sea Fault Zone (DSFZ); however, previous work has indicated kinematic inconsistency between its continental and oceanic parts. The Palmyra Fold Belt (PFB) splays ENE from the DSFZ in SW Syria and persists for ～400 km to the River Euphrates, but its significance within the regional pattern of active crustal deformation has hitherto been unclear. We report deformation of Euphrates terraces consistent with Quaternary right‐lateral transpression within the PFB, indicating anticlockwise rotation (estimated as 0.3° Ma?1 about 36.0°N 39.8°E) of the block between the PFB and the northern DSFZ relative to the Arabian Plate interior. The northern DSFZ is shown to be kinematically consistent with the combination of Euler vectors for the PFB and the Red Sea spreading, resolving the inconsistency previously evident. The SW PFB causes a significant earthquake hazard, previously unrecognized, to the city of Damascus.  相似文献   
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