Analysis of flood vulnerability and assessment of the impacts in coastal zones of Bangladesh due to potential sea-level rise     

Bhuiyan  Md. Jabed Abdul Naser  Dutta  Dushmanta 《Natural Hazards》2012,61(2):729-743

The 4th IPCC report highlights the increased vulnerability of the coastal areas from floods due to sea-level rise (SLR). The existing coastal flood control structures in Bangladesh are not adequate to adapt these changes and new measures are urgently necessary. It is important to determine the impacts of SLR on flooding to analyse the performance of the existing structures and corresponding impact to plan for suitable adaptation and mitigation measures to reduce the impacts of floods on coastal zone. The study aims to develop a comprehensive understanding of the possible effects of SLR on floods in the coastal zone of Bangladesh. A hydrodynamic model, which is a combination of surface and river parts, was utilized for flood simulation. The tool was applied under a range of future scenarios, and results indicate both spatial variability of risk and changes in flood characteristics between now and under SLR. Estimated impact on population, infrastructure and transportation is also exposed. These types of impact estimation would be of value to flood plain management authorities to minimize the socio-economic impact.  相似文献   

Textural characteristics of dust fallout and potential effect on public health in Kuwait City and suburbs     

Adeeba Essa Al-Hurban  Abdulaziz Naser Al-Ostad 《Environmental Earth Sciences》2010,60(1):169-181

The textural and mineralogical characteristics of the dust fallout along with the potential effect on human health were investigated at 12 locations in Kuwait City and suburbs during March 2006–February 2007. Mineralogically, the dust comprises mostly calcite and quartz with grain size ranging from 1 to 25 μm. Chemically, elements such as Ca, Fe, Mg, and Al are the dominant ones with the highest amount of average percentage concentration 12.89% for Ca. Results showed that humans in the 12 sites are being exposed to different ranges of average percentage concentrations of minerals such as calcite (15.00–51.80%), quartz (26.40–66.9%), albite (6.30–17.30%), dolomite (1.20–10.20%), and gypsum (0.00–6.4%), where site K3 recorded the lowest average concentrations for calcite, dolomite, and gypsum and the highest for quartz, and albite. The elements Ca, Fe, Mg, Al, K, Zn, Na, Cr, and Cd recorded ranges of (5.845–12.890%), (0.946–3.141%), (0.752–2.513%), (0.545–2.261%), (0.059–0.307%), (0.004–0.792%), (0.003–0.018%), (0.001–0.005%) and <0.0004%, respectively. Inhalation of such concentrations of calcite particles may cause coughing, sneezing, and nasal irritation, and in cases of chronic exposure to excessive oral doses of calcite may produce alkalosis and hypercalcemia. Quartz can have potentially serious respiratory effects following long-term exposure (1 year or more) which is the case here in our study. Comparing with international and local standards, it is highly likely that harmful and hazardous effects on the human body are being experienced by long-term exposure to dust fallout in Kuwait.  相似文献   

Ground-roll attenuation using modified common-offset–common-reflection-surface stacking     

Seyyed Ali Fa’al Rastegar  Abdolrahim Javaherian  Naser Keshavarz Farajkhah  Mehrdad Soleimani Monfared  Abbas Zarei 《应用地球物理》2016,13(2):353-363

We modified the common-offset–common-reflection-surface (COCRS) method to attenuate ground roll, the coherent noise typically generated by a low-velocity, low-frequency, and high-amplitude Rayleigh wave. The COCRS operator is based on hyperbolas, thus it fits events with hyperbolic traveltimes such as reflection events in prestack data. Conversely, ground roll is linear in the common-midpoint (CMP) and common-shot gathers and can be distinguished and attenuated by the COCRS operator. Thus, we search for the dip and curvature of the reflections in the common-shot gathers prior to the common-offset section. Because it is desirable to minimize the damage to the reflection amplitudes, we only stack the multicoverage data in the ground-roll areas. Searching the CS gathers before the CO section is another modification of the conventional COCRS stacking. We tested the proposed method using synthetic and real data sets from western Iran. The results of the ground-roll attenuation with the proposed method were compared with results of the f–k filtering and conventional COCRS stacking after f–k filtering. The results show that the proposed method attenuates the aliased and nonaliased ground roll better than the f–k filtering and conventional CRS stacking. However, the computation time was higher than other common methods such as f–k filtering.  相似文献   

咸海地区粉尘气溶胶动态变化及潜在扩散特征     

葛拥晓  阿力甫&#  那思尔  吉力力&#  阿不都外力  刘东伟 《中国沙漠》2016,36(5):1374-1380

咸海水位不断下降导致湖滨荒漠化加剧,尘暴频发,区域环境恶化。利用臭氧观测仪（OMI）气溶胶数据和HYSPLIT（Hybrid Single Particle Lagrangian Integrated Trajectory Model）模型,对咸海地区近期粉尘气溶胶变化及其潜在扩散特征进行了研究。结果表明：2005年以来,咸海地区粉尘活动不断增强,OMI气溶胶指数年平均值、方差、中值和最大值均呈现快速增加趋势,2013年OMI气溶胶指数平均值已经上升至1.47;OMI气溶胶指数具有明显的季节变化特征,春季（3-5月）和秋末初冬（11月-次年1月）是两个气溶胶指数峰值区;在相同时间内,春季和冬季的粉尘潜在扩散范围最大,秋季次之,夏季最小,且粉尘潜在扩散表现出明显的经向和纬向扩散特征;受气流和地形影响,粉尘潜在扩散主要有东北和西南两个方向。  相似文献   

Multisensor integration using neuron computing for land-vehicle navigation     

Kai-Wei Chiang  Aboelmagd Noureldin  Naser El-Sheimy 《GPS Solutions》2003,6(4):209-218

Most of the present navigation sensor integration techniques are based on Kalman-filtering estimation procedures. Although Kalman filtering represents one of the best solutions for multisensor integration, it still has some drawbacks in terms of stability, computation load, immunity to noise effects and observability. Furthermore, Kalman filters perform adequately only under certain predefined dynamic models. Neuron computing, a technology of artificial neural network (ANN), is a powerful tool for solving nonlinear problems that involve mapping input data to output data without having any prior knowledge about the mathematical process involved. This article suggests a multisensor integration approach for fusing data from an inertial navigation system (INS) and differential global positioning system (DGPS) hardware utilizing multilayer feed-forward neural networks with a back propagation learning algorithm. In addition, it addresses the impact of neural network (NN) parameters and random noise on positioning accuracy. Electronic Publication  相似文献   

A combined algorithm of improving INS error modeling and sensor measurements for accurate INS/GPS navigation   总被引：1，自引：1，他引：1  

Sameh Nassar  Naser El-Sheimy 《GPS Solutions》2006,10(1):29-39

Although the integrated system of a differential global positioning system (DGPS) and an inertial navigation system (INS) had been widely used in many geodetic navigation applications, it has sometimes a major limitation. This limitation is associated with the frequent occurrence of DGPS outages caused by GPS signal blockages in certain situations (urban areas, high trees, tunnels, etc.). In the standard mechanization of INS/DGPS navigation, the DGPS is used for positioning while the INS is used for attitude determination. In case of GPS signal blockages, positioning is provided using the INS instead of the GPS until satellite signals are obtained again with sufficient accuracy. Since the INS has a very short-time accuracy, the accuracy of the provided INS navigation parameters during these periods decreases with time. However, the obtained accuracy in these cases is totally dependent on the INS error model and on the quality of the INS sensor data. Therefore, enhanced navigation parameters could be obtained during DGPS outages if better inertial error models are implemented and better quality inertial measurements are used. In this paper, it will be shown that better INS error models are obtained using autoregressive processes for modeling inertial sensor errors instead of Gauss–Markov processes that are implemented in most of the current inertial systems and, on the other hand, that the quality of inertial data is improved using wavelet multi-resolution techniques. The above two methods are discussed and then a combined algorithm of both techniques is applied. The performance of each method as well as of the combined algorithm is analyzed using land-vehicle INS/DGPS data with induced DGPS outage periods. In addition to the considerable navigation accuracy improvement obtained from each single method, the results showed that the combined algorithm is better than both methods by more than 30%.  相似文献   

Does the Actual Drop in Dead Sea Level Reflect the Development of Water Sources Within its Drainage Basin?     

E. Salameh  H. Wl‐Naser 《洁净——土壤、空气、水》1999,27(1):5-11

As a part of Jordan’s efforts to quantify the effect of the Dead Sea level decline on the precious groundwater resources of the surrounding aquifers, the authors analyzed the historic or predevelopment inflows and outflows of the Dead Sea basin and the resulting water balance which included precipitation, evaporation, surface‐ and groundwaters. The predevelopment situation was taken as the point of departure for the sake of this study. Furthermore, the present situation was analyzed in an attempt to quantify the groundwater inflows into the Dead Sea as a result of drop in the Dead Sea level. The groundwater component and the corresponding saltwater/freshwater interface were taken as the variables to balance the levels of the sea that would have been reached without the contribution of the uncontrolled groundwater inflows as a result of the salt/freshwater interface seaward migration. The present day water balance that includes all the water diversion projects from all riparians indicates serious declines in the Dead Sea level. The effects of the present day level declines on the fresh groundwater/saltwater interface indicate that considerable amounts of groundwater are driven into the Sea as a result of the seaward migration of the freshwater/saline water interface.  相似文献   

Changes in the Dead Sea Level and their Impacts on the Surrounding Groundwater Bodies     

E. Salameh  H. El‐Naser 《洁净——土壤、空气、水》2000,28(1):24-33

In this paper the reaction of the salt‐/freshwater interface due to the changes in the Dead Sea level are elaborated at in details by using the inflows into the Dead Sea, the outflows due to evaporation losses and artificial discharges, and the hydrographic registrations of the Dead Sea level. The analyses show that the interface seaward migration resulted in a groundwater discharge of around 423 Mio m³ per meter drop in the level of the Dead Sea in the period 1994–1998 and of around 525 Mio m³/m in the period 1930–1937. The additional amount of groundwater joining the Dead Sea due to the interface seaward migration was 51 Mio m³ per one square kilometer of shrinkage in the area of the Dead Sea in the period 1930–1937 and 91 Mio m³/km² in the period 1994–1998. The riparian states of the Dead Sea are nowadays loosing 370 Mio m³/a of freshwater to the Dead Sea through the interface readjustment mechanisms as a result of their over exploitation of waters which formerly fed the Dead Sea.  相似文献   

Hazardous waste landfill site selection in Khorasan Razavi Province, Northeastern Iran   总被引：2，自引：0，他引：2  

Naser Hafezi Moghaddas  Hadi Hajizadeh Namaghi 《Arabian Journal of Geosciences》2011,4(1-2):103-113

The disposal is the final step of any hazardous waste management plan. An inappropriate landfill site may have negative environmental, economical, and ecological impacts. Therefore, landfills should be sited carefully by taking into account various rules, regulations, factors, and constraints. In this study, candidate sites for hazardous landfills in the northeastern Khorasan Razavi province are determined using the integration of geographic information system and landfill susceptibility zonation methods. For this, the inappropriate areas were first removed from the model, and the suitability of remaining regions were evaluated using 15 different criteria in two steps. With this done, nine candidate sites were selected as the most suitable locations. Finally, the selected landfill sites were proposed based on environmental impact assessment (Leopold matrix) and economical studies. This study shows that Maasumabad, Kheirabad, Mayamey, and Yonsi are the best locations for the constitution of landfill in Khorasan Razavi province, respectively.  相似文献   

Inherent heterogeneity of sediments in Dhahran, Saudi Arabia — a case study     

Naser A. Al-Shayea   《Engineering Geology》2000,56(3-4):305-323

The behavior and properties of sediments depend on their compositional characteristics and formation processes, as well as the environmental conditions during their geological history, i.e. post-formation processes. A vertical cut made in a hill in Dhahran, Saudi Arabia, reveals a vivid picture of the inherent heterogeneity of sediments that have been deposited at different geological ages. A review of the geology of the area, as well as laboratory tests, help to determine the possible causes of the variability of soil types and properties in the area. Laboratory tests include basic geotechnical tests, chemical tests, X-ray diffraction analysis, scanning electron microscopy, and thermal analysis. These tests are used to identify different rock types and soils from the face of the cut. The results of this study indicate that the material from this cut varies from clayey shale and limestone rock (Tertiary, lower Eocene) formed some 52 M.Y. to calcite-cemented sand and pure calcite rock formed in the Quaternary age.  相似文献