地貌特征对约旦南部阿尔阿加河(WadiAl-Arja)流域产沙影响分析(英文)   总被引：1，自引：0，他引：1  

Ali Hamdi ABU SALIM 《地理学报(英文版)》2014,24(3):457-474

This study addresses the morphometric variables that determine the sediment yield in Wadi Al-Arja through the analysis of the impact of different morphometric characteristics along the course of the valley on its sediment yield, as well as the analysis of spatial and formal dimensions and morphologies of the basin and its relationship to the sediment yield. The study also addresses the size of variation in the volume of sediment yield of the river tributaries that make up the water network of the valley under the differences of its morphometric and hydrological characteristics. The study found several results, most notably: The classification of Wadi Al-Arja basin according to the hypsometric integral value(72.1%) within an uneven topography, which increases the force of the erosive activity and the size of the sediment yield if the basin was exposed to moist climatic periods. The study also showed the presence of convergence in the intra-spaces between the river tributaries in the water network. This increases the volume of water flows when these tributaries meet with each other and thus increasing their erosive ability and sediment yield. The study also showed the presence of marked variation in the sediment yield of the river tributaries depending on the differences in its morphometric characteristics. The results of the step-wise regression analysis confirmed the importance of the morphometric and hydrological variables, and plant coverage in interpreting the variation in the size of the sediment yield of the river tributaries of different stream order in Wadi Al-Arja basin, where these variables interpreted 43% of the total variation, with statistical significance less than 0.05.  相似文献   

Mobility of rare earth elements in the system soils–plants–groundwaters: a case study of an arid area (Oman)     

Khadija Semhi  Osman A. E. Abdalla  Salah Al Khirbash  Tabisam Khan  Salim Asaidi  Sardar Farooq 《Arabian Journal of Geosciences》2009,2(2):143-150

Groundwater samples from six wells and various species of plants from soils developed on ophiolites were collected from an arid area (AlKhod area, Oman) and analyzed for trace elements including rare earth elements (REEs). The distribution patterns of REEs in plants indicated an enrichment in middle REEs (MREEs?=?Sm to Dy) and heavy REEs (HREEs?=?Ho to Lu), when they are normalized to the REE composition of the Post Archean Australian Shale (PAAS), with a significant negative anomaly in Ce and a positive anomaly in Eu. Compared to Oman ophiolites, the REEs in different species of plants are depleted in Ce and enriched in MREEs and slightly enriched in light REE (LREE?=?from La to Nd). Relative to PAAS, the distribution of REEs in groundwaters revealed similar patterns to the REE distribution in plants. The distribution patterns of REEs in plants relative to those in waters are nearly flat. These patterns suggest that the transfer of REEs from soil solutions to the groundwaters in Oman occurs without any significant fractionation.  相似文献   

New information on radionuclides concentration in phosphorites originating from Tunisia and Algeria     

Jaloul Bejaoui  Mohamed Samaali  Souad Baccouche  Nafaa Regugui  Mohamed Fethi Ben Hamouda  Zohra Azzouz  Adel Trabelsi  Salah Bouhlel  Boulamia Salim 《Arabian Journal of Geosciences》2013,6(7):2685-2689

In this study we investigate the radiological hazard of naturally occurring radioactive material in Tunisian and Algerian phosphorite deposits. Eight samples of phosphorite were collected from the phosphorite mines. The Tunisian and Algerian phosphorites occur in the Late Paleocene and Lower Eocene (Ypresian-Lutetian) in age (Béji Sassi 1984 and Zaïer 1999). Activity concentrations in all the samples were measured by alpha spectrometry and gamma spectrometry. Alpha spectrometry analyses show that the specific activity values of ²³⁸U, ²³⁴U and ²³⁵U in the samples of Tunisian phosphorite were 327?±?7 (321–327), 326?±?6 (325–331) and 14.50?±?0.72 (13.90–15.57) Bq kg^?1, respectively. Specific activity measured by gamma spectrometry in the samples of the Tunisian and Algerian phosphorite shows a small difference. Specific activity levels of ⁴⁰K, ²²⁶Ra, ²³²Th, ²³⁵U and ²³⁸U in the phosphorite samples from Tunisia were, respectively, 71.10?±?3.80, 391.54?±?9.39, 60.38?±?3.74, 12.72?±?0.54 and 527.42?±?49.57 Bq kg^?1 and Algeria were 15.72?±?1.73, 989.65?±?12.52, 12.08?±?1.20, 47.50?±?1.52 and 1,148.78?±?7.30 Bq kg^?1, respectively. The measured value of specific activity of ²³²Th and ⁴⁰K in the Tunisian phosphorite samples is relatively higher than that found in the samples of Algerian phosphorite. The measured activity of uranium (²³⁸U) in the Tunisian phosphorite (527?±?49) Bq kg^?1 is lower than in Algerian phosphorite. The measured activity of ²³⁸U in the Tunisian phosphorite samples was (527–1,315?±?65) ²³⁸U Bq kg^?1 which is higher than its maximum background value of 110 Bq kg^?1 in soils of the various countries of the world (Tufail et al. Radiat Meas 41:443–451, 2006). Different geological origins of phosphorites deposits are the main reason for the large spread in worldwide specific activities. The obtained results of uranium concentrations in phosphorites of different types (Algerian and Tunisian) demonstrate that the uranium concentrations are mainly governed by the phosphatic material. The present study reveals that phosphorite deposits contain natural radioactivity higher than background level.  相似文献   

Seismic spectrograms of an anelastic layer with different source-receivers configurations     

Ayman N. Qadrouh  José M. Carcione  Ahmed M. A. Salim  Zuhar Zahir Tuan Harith 《Arabian Journal of Geosciences》2016,9(5):413

Thin and relatively thin anelastic layers (compared to the signal wavelength) generally represent hydrocarbon reservoirs, where the rock is a sandstone or a source rock saturated with brine, oil and gas. The study of the seismic response of these layers is important to detect the hydrocarbons on the basis of the reflection and transmission coefficients and the wave velocity and attenuation properties. Different seismic experiments (source-receiver configurations) can provide useful information to characterise its properties. In this work, we consider varying thicknesses and Q values of the layer and analyse the reflection and transmission coefficients. Moreover, we obtain spectrograms of surface seismic profiles and vertical and horizontal well profiles (VSP and HSP, respectively) to analyse their frequency content with offset due to variations of the attenuation properties of the layer. In addition, we compare the effects due to NMO stretching and intrinsic attenuation related to the low-frequency shadows (LFS) observed in real data after stacking, since LFS can have several causes. Ambiguity is present in this case, indicating that non-stretch NMO is required, otherwise an offset mute of the data may remove useful information regarding the intrinsic (physical) loss.  相似文献   

Assessment of SARAL-ALTIKA Tidal Corrections in the Coastal Oceans Around India     

R. K. Nayak  M. Salim  S. K. Sasamal  P. C. Mohanthy  R. K. Bharadwaj  K. H. Rao 《Marine Geodesy》2016,39(5):331-347

The present tidal correction of sea level records of Satellite with ARgoes and ALtimeter (SARAL) is based on the finite element solution (FES) of global tide model FES2012 tidal solution. In this study, we examined the validity of the tidal corrections in the coastal oceans around India using tide gauge measurements and a regional tidal model. Our regional model is based on the barotropic version of the Princeton Ocean Model that is forced by the time-varying tidal levels at the open ocean end based on the global FES99 tidal solution. Tide charts prepared from the simulated tidal levels are very similar to the FES tidal solutions. Comparison with the tide gauge measurement shows close agreement with the regional tidal solutions. On the other hand, the agreement with the FES tide models differ significantly in the Gulf of Khambhat and the Gulf of Kutch on the northwest, and in the Hooghly estuary on the northeast continental shelf. However, the agreement is exceptional in other parts of the study domain. These tidal solutions are used in the SARAL-ALTIKA X-track data to assess the FES tidal correction and to draw some inferences associated with the coastal processes. It is revealed that these corrections are reasonably accurate for the coastal oceans around India except the aforementioned converging channels.  相似文献   

The changing social relations of a community-based mangrove forest project in Zanzibar     

Fred Saunders  Salim M. Mohammed  Narriman Jiddawi  Karolina Nordin  Bengt Lundèn  Sara Sjöling 《Ocean & Coastal Management》2010,53(4):150-160

Coastal areas in East Africa are experiencing rapid economic, resource management, demographic and technological shifts. In response diverse Community-based Natural Resource Management (CBNRM) applications have been embraced to provide mutual conservation and use benefits. These initiatives have met with mixed success in practice. Reflecting on the limitations of past research using common pool resources theory theory to study CBNRM we use insights from actor oriented theory combined with satellite image analysis to describe and discuss the forces dynamically influencing institutional and mangrove forest cover change at Kisakasaka, Zanzibar focussing on the formal CBNRM project period between 1996 and 2001, but also considering the period before and after this. We examine the shifting social relations that affected the performance and viability of the formal CBNRM arrangements. An integrated approach was taken to the presentation and discussion of results where it was possible to enrich and expand explanations of socio-environmental change, which was driven by a lack of government support, the undermining effects of party political divisions, and the lack of institutional adaptive capacity. We conclude that this was a useful approach to explain CBNRM intervention events at Kisakasaka.  相似文献   

The correlation of star formation quenching with internal galaxy properties and environment     

Taysun Kimm  Rachel S. Somerville  Sukyoung K. Yi  Frank C. van den Bosch  Samir Salim  Fabio Fontanot  Pierluigi Monaco  Houjun Mo  Anna Pasquali  R. M. Rich  Xiaohu Yang 《Monthly notices of the Royal Astronomical Society》2009,394(3):1131-1147

We investigate the correlation of star formation quenching with internal galaxy properties and large-scale environment (halo mass) in empirical data and theoretical models. We make use of the halo-based group catalogue of Yang and collaborators, which is based on the Sloan Digital Sky Survey. Data from the Galaxy evolution explorer are also used to extract the recent star formation rate. In order to investigate the environmental effects, we examine the properties of 'central' and 'satellite' galaxies separately. For central galaxies, we are unable to conclude whether star formation quenching is primarily connected with halo mass or stellar mass, because these two quantities are themselves strongly correlated. For satellite galaxies, a nearly equally strong dependence on halo mass and stellar mass is seen. We make the same comparison for five different semi-analytic models based on three independently developed codes. We find that the models with active galactic nuclei feedback reproduce reasonably well the dependence of the fraction of central red and passive galaxies on halo mass and stellar mass. However, for satellite galaxies, the same models badly overproduce the fraction of red/passive galaxies and do not reproduce the empirical trends with stellar mass or halo mass. This satellite overquenching problem is caused by the too-rapid stripping of the satellites' hot gas haloes, which leads to rapid strangulation of star formation.  相似文献   

Time series forecasting of river flow using an integrated approach of wavelet multi-resolution analysis and evolutionary data-driven models. A case study: Sebaou River (Algeria)     

Mousaab Zakhrouf  Hamid Bouchelkia  Madani Stamboul  Sungwon Kim  Salim Heddam 《自然地理学》2018,39(6):506-522

The complexity of hydrological processes and lack of data for modeling require the use of specific tools for non-linear natural phenomenon. In this paper, an effort has been made to develop a conjunction model – wavelet transformation, data-driven models, and genetic algorithm (GA) – for forecasting the daily flow of a river in northern Algeria using the time series of runoff. This catchment has a semi-arid climate and strong variability in runoff. The original time series was decomposed into multi-frequency time series by wavelet transform algorithm and used as inputs to artificial neural networks (ANN) and adaptive neuro-fuzzy inference system (ANFIS) models. Several factors must be optimized to determine the best model structures. Wavelet-based data-driven models using a GA are designed to optimize model structure. The performances of wavelet-based data-driven models (i.e. WANFIS and WANN) were superior to those of conventional models. WANFIS (RMSE = 12.15 m³/s, EC = 87.32%, R = .934) and WANN (RMSE = 15.73 m³/s, EC = 78.83%, R = .888) models improved the performances of ANFIS (RMSE = 23.13 m³/s, EC = 54.11%, R = .748) and ANN (RMSE = 22.43 m³/s, EC = 56.90%, R = .755) during the test period.  相似文献   

Spatial-temporal changes of NDVI and their relations with precipitation and temperature in Yangtze River basin from 1981 to 2001     

Li Zhang  Xiaoling Chen  Xiaobin Cai  Habib Aziz Salim 《地球空间信息科学学报》2010,13(3):186-190

Multitemporal NOAA/AVHRR NDVI images and monthly temperature and precipitation data were obtained across Yangtze River basin covering the period 1981–2001. The spatial and temporal patterns of NDVI are the same, while spatial analysis shows that the NDVI is influenced by the vegetation types growing in the study regions, and NDVI presents an increasing trend during the study period in the whole basin. The climate indicators play an important role in the changes of vegetation cover in the river basin. In the two Indicators, temperature has a significant effect on the NDVI values than precipitation in the whole basin. However, in the 11 subbasins, the different rules are shown in different subbasins.  相似文献   

Green and Eco‐Friendly Removal of Mycotoxins with Organo‐Bentonites; Isothermal,Kinetic, and Thermodynamic Studies     

Muhammad Saeed  Komal Farooq  Muhammad Nafees  Muhammad Arshad  Mohammad Salim Akhter  Amir Waseem 《洁净——土壤、空气、水》2020,48(9)

In the current study the application of organo‐modified bentonite for the adsorption of mycotoxins (aflatoxin B1, citrinin, patulin, and zearalenone) is presented. The modification of clays is carried out using benzyl‐tri‐n‐butyl ammonium bromide (BTB), benzethonium chloride (BTC), and dioctyl sodium sulfosuccinate (DSS). Various experimental parameters such as pH, time, adsorbent dose, and mycotoxins concentration are thoroughly studied. The modified clays (B‐BTB, B‐BTC and B‐DSS) are characterized by X‐ray fluorescence, X‐ray diffraction, and Fourier transform infrared spectroscopy. The results depicted the high detoxification efficiency (≈99%) of modified clays for the removal of mycotoxins under optimized conditions (pH 5, time: 30 min, adsorbent amount: 50 mg). The adsorption capacities of modified clays are found in the order of: B‐BTC (AFB1: 18.02, CIT: 18.35, PAT: 18.21, ZEA: 18.09 mg g^?1) > B‐BTB (AFB1: 17.7, CIT: 18.11, PAT: 17.95, ZEA: 17.90 mg g^?1) > B‐DSS (AFB1: 17.5, CIT: 18.02, PAT: 17.86, ZEA: 17.80 mg g^?1). The obtained results fitted well with thermodynamic, isothermal (Langmuir) and pseudo‐second order kinetics. Low cost organo‐modified bentonite shows the promise in mitigating mycotoxin contamination, which could improve food safety and reduce environmental contamination.  相似文献