Characterization of complex fluvial systems using remote sensing of spatial and temporal water level variations in the Amazon,Congo, and Brahmaputra Rivers   总被引：1，自引：0，他引：1  

Hahn Chul Jung  James Hamski  Michael Durand  Doug Alsdorf  Faisal Hossain  Hyongki Lee  A. K. M. Azad Hossain  Khaled Hasan  Abu Saleh Khan  A.K.M. Zeaul Hoque 《地球表面变化过程与地形》2010,35(3):294-304

The Surface Water and Ocean Topography (SWOT) satellite mission will provide global, space‐based estimates of water elevation, its temporal change, and its spatial slope in fluvial environments, as well as across lakes, reservoirs, wetlands, and floodplains. This paper illustrates the utility of existing remote sensing measurements of water temporal changes and spatial slope to characterize two complex fluvial environments. First, repeat‐pass interferometric SAR measurements from the Japanese Earth Resources Satellite are used to compare and contrast floodplain processes in the Amazon and Congo River basins. Measurements of temporal water level changes over the two areas reveal clearly different hydraulic processes at work. The Amazon is highly interconnected by floodplain channels, resulting in complex flow patterns. In contrast, the Congo does not show similar floodplain channels and the flow patterns are not well defined and have diffuse boundaries. During inundation, the Amazon floodplain often shows sharp hydraulic changes across floodplain channels. The Congo, however, does not show similar sharp changes during either infilling or evacuation. Second, Shuttle Radar Topography Mission measurements of water elevation are used to derive water slope over the braided Brahmaputra river system. In combination with in situ bathymetry measurements, water elevation and slope allow one to calculate discharge estimates within 2.3% accuracy. These two studies illustrate the utility of satellite‐based measurements of water elevation for characterizing complex fluvial environments, and highlight the potential of SWOT measurements for fluvial hydrology. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

Variation in the life-history traits of a Schilbid catfish,Clupisoma garua (Hamilton, 1822) in the coastal waters of southern Bangladesh     

Siddik  Muhammad Abu Bakar  Chaklader  Md Reaz  Hanif  Md Abu  Nahar  Ashfaqun  Ilham  Ilham  Cole  Anthony  Fotedar  Ravi 《中国海洋湖沼学报》2017,35(5):1189-1196

For the first time,the present study reports the life-history traits,comprising length-frequency distribution(LFD),sex ratio(SR),length-weight relationships(LWRs),condition factors(CFs),and relative growth(W_R),of Clupisoma garua in the coastal waters of Bangladesh.A total of 150 specimens ranging from 8.60 to 25.20 cm total length(TL)and 4.26 to 128.80 g body weight(BW)were collected using traditional fishing gear from August 2013 to July 2014.The overall sex ratio of males to females in the study did not dif fer significantly from the expected value of 1:1(χ~2=0.96,P0.05)but there were significant sex differences(P0.05)in the intercepts and slopes of graphs characterizing traits in C.garua.The calculated bvalues for the LWRs were 2.955,2.893 and 2.927 for males,females and combined sexes,respectively,and there was negative allometric growth in all cases(b3).The condition factors(K_A,K_F,K_R)and relative growth(W R)also did not differ significantly(P0.05)between the sexes.This study provides a useful tool for fi shery specialists to evaluate the relative condition of fish and to initiate early management strategies and regulations for the sustainable management of the remaining stocks of this species in the entire coastal region of southern Bangladesh.  相似文献   

Extension-related buttress-like folds,the western side of the Gulf of Suez rift,Egypt     

Abu Sharib  A. S. A. A.  Abdel-Fattah  M. M.  Salama  Y. F.  Abdel-Gawad  G. I. 《International Journal of Earth Sciences》2017,106(7):2527-2547

International Journal of Earth Sciences - The wedge-shaped St. Paul block, western side of the Gulf of Suez rift, exposes Late Cretaceous beds that are folded into transverse folds. The block is...  相似文献   

Groundwater beneath the urban area of Khan Younis City,southern Gaza Strip (Palestine): assessment for multi-domestic purposes     

Mohd S. Abu Jabal  Ismail Abustan  Mohd Remy Rozaimy  Hussam El Najar 《Arabian Journal of Geosciences》2017,10(12):257

The present study research investigation is aimed to assess the groundwater quality for the urban area in Khan Younis City, southern Gaza Strip, for multi-domestic purposes. The physicochemical analysis of the groundwater wells shows the major ions in the order of Na⁺ > Mg²⁺ > Ca²⁺ > B³⁺ > K⁺ and Cl^? > HCO₃ ^? > SO₄ ^2? > NO₃ ^2? > F^? > PO₄ ^3?. Groundwater quality is classified as very hard-brackish water type. Ninety-five percent of the wells are classified as saline water type with high NO₃ ^2? concentrations. Based on water quality index (WQI), the groundwater falls into one of three categories: fair water (10%), poor water (15%), very poor (45%), and worst (30%). The high WQI values are because of high Na⁺, Cl^?, SO₄ ^2?, and NO₃ ^2? concentrations, while synthetic pollution index (SPI) values indicate that most about 80% of the wells are seriously polluted. Langelier Saturation Index (LSI) indicates that most of data are either slightly scale forming or corrosive water or slightly corrosive but non-scale forming, and 75% of the wells are suitable for construction purposes (have SO₄ ^2? concentrations <300 mg/L). The groundwater reaches alarming situation, where almost chemically unsuitable for drinking purposes and the water to be used after proper treatment such as desalination.  相似文献   

Illuminating and optimising a three‐dimensional model of an oil shale seam and its volume distribution using the transient electromagnetic induction method,central part of Jordan          下载免费PDF全文

Jafar Sadi Abu Rajab  Eid Al Tarazi 《Geophysical Prospecting》2018,66(3):603-625

The oil shale exploration program in Jordan is undertaking great activity in the domain of applied geophysical methods to evaluate bitumen‐bearing rock. In the study area, the bituminous marl or oil shale exhibits a rock type dominated by lithofacies layers composed of chalky limestone, marls, clayey marls, and phosphatic marls. The study aims to present enhancements for oil shale seam detection using progressive interpretation from a one‐dimensional inversion to a three‐dimensional modelling and inversion of ground‐based transient electromagnetic data at an area of stressed geological layers. The geophysical survey combined 58 transient electromagnetic sites to produce geoelectrical structures at different depth slices, and cross sections were used to characterise the horizon of the most likely sites for mining oil shale. The results show valuable information on the thickness of the oil shale seam at 3.7 Ωm, which is correlated to the geoelectrical layer between 2‐ and 4 ms transient time delays, and at depths ranging between 85 and 105 m. The 300 m penetrated depth of the transient electromagnetic soundings allows the resolution of the main geological units at narrow resistivity contrast and the distinction of the main geological structures that constrain the detection of the oil shale seam. This geoelectrical layer at different depth slices illustrates a localised oil shale setting and can be spatially correlated with an area bounded by fold and fault systems. Also, three‐dimensional modelling and inversion for synthetic and experimental data are introduced at the faulted area. The results show the limitations of oil shale imaging at a depth exceeding 130 m, which depends on the near‐surface resistivity layer, the low resistivity contrast of the main lithological units, and the degree of geological detail achieved at a suitable model's misfit value.  相似文献   

Untapped Economic Resource Potential of the Neoproterozoic to Early Paleozoic Volta Basin,Ghana: A Review     

Abu  Mahamuda  Sunkari  Emmanuel Daanoba  Şener  Mehmet 《Natural Resources Research》2019,28(4):1429-1445

Natural Resources Research - The ~?115,000&nbsp;km2 Volta Basin of Ghana is one of the most studied geological terrains. However, unlike the Birimian and Tarkwaian which have been...  相似文献   

南海中尺度涡温盐结构的季节特征及形成机制   总被引：2，自引：0，他引：2  

祖永灿  孙双文  赵玮  李培良  刘宝超  方越  Samah Azizan Abu 《海洋学报(英文版)》2019,38(4):29-38

本文利用最新的涡旋数据集和ARMOR3D数据,研究了南海中尺度涡温盐结构的季节特征及形成机制。合成分析的结果表明,在冬季,涡旋引起温度异常的水平分布在50米以浅表现为类似偶极型分布,而在50m以深则趋向于中心对称分布;在夏季,温度异常的水平分布均表现为中心对称的特征。涡旋引起盐度异常的水平分布也具有类似的季节特征,但是偶极型中的不对称性相对较弱。在垂向上,涡旋所致的温度异常表现为单层结构,而盐度异常则为三层结构。进一步的分析表明,涡旋所致温盐异常的垂向分布特征与背景温盐的垂向分层有关;而在50m以浅,温盐异常的水平分布的不对称特征主要由背景温盐场的水平平流所致。  相似文献   

Deformation-induced cordierite breakdown–An example from western Maine,USA     

Ioan V. Sanislav  Ahmed S. A. A. Abu Sharib  Raphael S. A. Quentin de Gromard 《Journal of Metamorphic Geology》2020,38(8):831-852

Preservation of partially completed metamorphic reactions in the form of partial pseudomorphs is very important as it provides direct insight onto the reaction mechanism and the phases involved in the reaction. The staurolite and andalusite grade rocks in western Maine, USA, contain cordierite porphyroblasts partly pseudomorphed by coarse-grained muscovite and biotite. The pseudomorphs consist of a cordierite core surrounded by a reaction rim. Modal mineralogy, calculated using the ImageJ processing software based on backscatter images and X-ray compositional maps, reveals that the core consists of cordierite (53.5%), muscovite (22.8%), biotite (9.1%), quartz (1 0.4%), plagioclase (3.1%) and ilmenite/pyrrhotite and apatite (1.1%) whereas the reaction rim consists of cordierite (1.8%), muscovite (51.6%), biotite (30.4%), quartz (4.3%), plagioclase (10%), garnet (1.2%), ilmenite/pyrrhotite and apatite (0.8%). The net effect of the cordierite breakdown reaction is an increase of 226% in muscovite, 334% in biotite and 323% in plagioclase content and a decrease of 97% in cordierite. The reaction involved exchange of components with the matrix requiring addition of H₂O, K⁺, Na⁺ and Ti⁴⁺ and removal of SiO₂, Mg²⁺ and PO₄^3- from the reaction site. PT estimates using the garnet–biotite, Ti-in-biotite, Na-in-cordierite thermometers and the garnet–biotite–muscovite–plagioclase barometer indicate that cordierite breakdown occurred at ~550°C and 3.5 kbar. thermocalc modelling using the bulk rock composition suggests that cordierite is not stable at these conditions, whereas modelling using a thin section-derived bulk composition indicates that cordierite stability extends to higher pressures, and most likely that the cordierite breakdown was not PT dependent. The incorporation of Na (up to 0.18 a.f.u.) into the cordierite structure has the effect of stabilizing the cordierite under a variety of H₂O activity and limiting the role of fluids into destabilizing it. The cordierite cores contain evidence of plastic and brittle deformation in the form of subgrains and microcracks, which facilitated the infiltration of fluids that destabilized cordierite at constant PT conditions by leaching Na and introducing K. New mica growth along these structural heterogeneities suggests that deformation played an important role promoting breakdown of cordierite to muscovite and biotite.  相似文献   

Correction to: Nexus between vulnerability and adaptive capacity of drought-prone rural households in northern Bangladesh     

Salam  Roquia  Islam  Abu Reza Md. Towfiqul  Shill  Badhon Kumar  Alam  G. M. Monirul  Hasanuzzaman  Md.  Hasan  Md. Morshadul  Ibrahim  Sobhy M.  Shouse  Roger C. 《Natural Hazards》2021,106(1):529-529

Natural Hazards - The article was published with a spelling error in one of the co-author names. The correct spelling is reflected in this correction, and the original work has been updated to...  相似文献   

U–Pb TIMS age constraints on the evolution of the Neoproterozoic Meatiq Gneiss Dome,Eastern Desert,Egypt     

Arild Andresen  Mohamed Ali Abu El-Rus  Per Inge Myhre  Gamal Y. Boghdady  Fernando Corfu 《International Journal of Earth Sciences》2009,98(3):481-497

Ages are used to constrain the temporal evolution of the Meatiq Gneiss Dome, Eastern Desert, Egypt, by dating (ID-TIMS) pre-, syn-, and post-tectonic igneous rocks in and around the dome. The Um Ba’anib Orthogneiss, comprising the deepest exposed structural levels of the dome, has a crystallization age of 630.8 ± 2 Ma. The overlying mylonites are interpreted to be a thrust sheet/complex (Abu Fannani Thrust Sheet) of highly mylonitized metasediments (?), migmatitic amphibolites, and orthogneisses with large and small tectonic lenses of less-deformed intrusives. Two syn-tectonic diorite lenses in this complex have crystallization ages of 609.0 ± 1.0 and 605.8 ± 0.9 Ma, respectively. The syn-tectonic Abu Ziran diorite, cutting across the tectonic contact between mylonite gneisses of the Abu Fannani Thrust Sheet and a structurally overlying thrust sheet of eugeoclinal rocks (“Pan-African nappe”), has a magmatic emplacement age of 606.4 ± 1.0 Ma. Zircons from a gabbro (Fawakhir ophiolite) within the eugeoclinal thrust sheet yielded a crystallization age of 736.5 ± 1.2 Ma. The post-tectonic Fawakhir monzodiorite intrudes the ophiolitic rocks and has an emplacement age of 597.8 ± 2.9 Ma. Two other post-tectonic granites, the Arieki granite that intrudes the foliated Um Ba’anib Orthogneiss, and the Um Had granite that cuts the deformed Hammamat sediments, have emplacement ages of 590 ± 3.1 and 596.3 ± 1.7 Ma, respectively. We consider formation of the Meatiq Gneiss Dome to be a young structural feature (<631 Ma), and our preferred tectonic interpretation is that it formed as a result of NE–SW shortening contemporaneous with folding of the nearby Hammamat sediments around 605–600 Ma, during oblique collision of East and West Gondwana.  相似文献