Automatic Feature Extraction Module for Change Detection in Al Ain,UAE: Analysis by Means of Multi-temporal Remote Sensing Data

Monitoring new changes in cities adjacent to dynamic sand dunes requires precise classifier technique. Unlike traditional techniques of supervised classification which use training sites, the integration of image transformation tasseled cap and automatic feature extraction module based on spectral signatures has provided to be sensitive and realistic techniques with time and cost effective. The proposed module was applied to Al Ain district, United Arab Emirates (UAE). The module consists of four steps in terms of segmentation, thresholding and clustering and computing attributes. The obtained greenness and classified maps were then enhanced by applying a 3?×?3 Sobel filter. The new changes were detected by combining the multi-temporal greenness and classification maps. Accuracy assessment and quantitative analysis were performed using confusion matrix and ground truthing. The results showed significant increasing in urban and agricultural areas from the year from 1990 to 2000 compared with the period of time from the year 2000 to 2006. The image difference showed that the vegetation and building classes had increased 7.58 and 20.28 km² respectively. This study showed that image difference and fuzzy logic approach are the most sensitive techniques for detecting new changes in areas adjacent to dynamic sand dunes.     

Height-season structure of the available potential energy and kinetic energy in the lower and middle atmosphere

The distributions of kinetic energy (KE) and available potential energy (APE) in the lower and middle atmosphere of the Northern and Southern hemispheres over the period 1992–2003 are investigated. Annual mean values of the amplitude and phase of annual and semiannual oscillations in the zonal and eddy forms of KE and APE are calculated in the height range 0–55 km (1000–0.316 hPa) for the 21st layer. A clearly pronounced annual cycle of the zonal and eddy components of KE and APE with maxima in the winter season are observed in the troposphere of both hemispheres. In the lower stratosphere, the annual-cycle maximum is shifted toward the summer season because of the meridional gradient of the zonal mean temperature. In the stratosphere of both hemispheres, along with annual oscillations, semiannual oscillations are present in all forms of energy. The intensity of these oscillations for the zonal KE and APE at the upper-stratosphere heights is comparable to the intensity of annual oscillations. A local structure of the energy regime of the upper mesosphere-lower thermosphere is investigated against the background of the global energy regime from the data of meteor sounding in Kazan. It is shown that, for both the global and regional regimes, specific features of the phase profiles of energy characteristics can be explained by the presence of barriers during the propagation of wave disturbances along the vertical.     

Monazite chemistry: evidence for a prehistoric journey

The chemistry of monazite from the black sand deposits of northern Sinai beach suggests that pegmatites and granites of the Eastern Desert of Egypt are the most likely source rocks. The floods associated with the pluvial periods prevailed in Egypt during the Pleistocene were able to erode the source rocks and liberate heavy minerals including monazite. The mineral grains were moved through several wadis and tributaries to the River Nile. At the confluence sites, these heavy minerals were mixed with the Ethiopian and central African heavy mineral assemblages. The grains continued to move together downriver until being deposited in their current locations.     

Tectonometamorphic evolution of an intracontinental orogeny inferred from P–T–t–d paths of the metapelites from the Rehamna massif (Morocco)

New petrographic and microstructural observations, mineral equilibria modelling and U/Pb (monazite) geochronological studies were carried out to investigate the relationships between deformation and metamorphism across the Rehamna massif (Moroccan Variscan belt). In this area, typical Barrovian (muscovite to staurolite) zones developed in Cambrian to Carboniferous metasedimentary rocks that are distributed around a dome‐like structure. First assemblages are characterized by the presence of locally preserved andalusite, followed by prograde evolution culminating at 6 kbar and 620 °C in the structurally deepest staurolite zone rocks. This Barrovian sequence was subsequently uplifted to supracrustal levels, heterogeneously reworked at greenschist facies conditions, which was followed locally by static growth of andalusite, indicating heating to 2.5–4 kbar and 530–570 °C. The ²⁰⁶Pb/²³⁸U monazite age of 298.3 ± 4.1 Ma is interpreted as minimum age of peak metamorphic conditions, whereas the ages of 275.8 ± 1.7 Ma and 277.0 ± 1.1 Ma date decompression and heating at low pressure, in agreement with previous dating of Permian granitoids intruding the Rehamna massif. The prograde metamorphism occurred during thickening and associated horizontal flow in the deeper crust (S1 horizontal schistosity). The horizontally disposed metamorphic zones were subsequently uplifted by a regional scale antiform during ongoing N–S compression. The re‐heating of the massif follows late massive E–W shortening, refolding and retrograde shearing of all previous fabrics coevally with regionally important intrusions of Permian granitoids. We argue that metamorphic evolution of the Rehamna massif occurred several hundred kilometres from the convergent plate boundaries in the interior of continental Gondwanan plate. The tectonometamorphic history of the Rehamna massif is put into Palaeozoic plate tectonic perspective and Late Carboniferous reactivation of (Devonian)–Early Carboniferous basins formed during stretching of the north Gondwana margin and formation of the Palaeotethys Ocean. The inherited heat budget of these magma‐rich basins plays a role in the preferential location of this intracontinental orogen. It is shown that rapid transition from lithospheric stretching to compression is characterized by specific HT type of Barrovian metamorphism, which markedly differs from similar Barrovian sequences along Palaeozoic plate boundaries reported from Variscan Europe.     

Forced vertical and horizontal movements of a rectangular rigid foundation on a transversely isotropic half‐space

An analytical investigation of a half‐space containing transversely isotropic material under forced vertical and horizontal displacements applied on a rectangular rigid foundation is presented in this paper. With the goal of a rigorous solution to the shape‐ and rigidity‐ induced singular mixed boundary value problem, the formulation employs scalar potential representation, the Fourier expansion and the Hankel integral transforms method to obtain the surface arbitrary point‐load solution in cylindrical coordinate system. The obtained Green's functions are rewritten in rectangular coordinate system, allowing the response of the half‐space because of an arbitrary distributed load on a rectangular surface area be given in terms of a double integral. The numerical evaluations of stresses are done with the use of an element, which is singular at the edge and the corner of the rectangle. Upon the imposition of the rigidity displacement boundary condition for a rigid foundation and the use of a set of two‐dimensional adaptive‐gradient elements, which can capture the singular behavior in the contact stress effectively, a set of new numerical results are presented to illustrate the effect of transverse isotropy on the foundation response. Copyright © 2012 John Wiley & Sons, Ltd.     

Performance of a conceptual and physically based model in simulating the response of a semi‐urbanized watershed in San Antonio,Texas

The need for accurate hydrologic analysis and rainfall–runoff modelling tools has been rapidly increasing because of the growing complexity of operational hydrologic and hydraulic problems associated with population growth, rapid urbanization and expansion of agricultural activities. Given the recent advances in remote sensing of physiographic features and the availability of near real‐time precipitation products, rainfall–runoff models are expected to predict runoff more accurately. In this study, we compare the performance and implementation requirements of two rainfall–runoff models for a semi‐urbanized watershed. One is a semi‐distributed conceptual model, the Hydrologic Engineering Center‐Hydrologic Modelling System (HEC‐HMS). The other is a physically based, distributed‐parameter hydrologic model, the Gridded Surface Subsurface Hydrologic Analysis (GSSHA). Four flood events that took place on the Leon Creek watershed, a sub‐watershed of the San Antonio River basin in Texas, were used in this study. The two models were driven by the Multisensor Precipitation Estimator radar products. One event (in 2007) was used for HEC‐HMS and GSSHA calibrations. Two events (in 2004 and 2007) were used for further calibration of HEC‐HMS. Three events (in 2002, 2004 and 2010) were used for model validation. In general, the physically based, distributed‐parameter model performed better than the conceptual model and required less calibration. The two models were prepared with the same minimum required input data, and the effort required to build the two models did not differ substantially. Copyright © 2012 John Wiley & Sons, Ltd.     

Implementing Digital Imaging for Improved Understanding of Microfine Cement Grout Permeation and Filtration

Geotechnical and Geological Engineering - Permeation grouting is a ground improvement method commonly used for strengthening and/or reducing permeability of soils with minimal disturbance to the...     

Tonian–Ediacaran Tectonometamorphic History of the Sa’al Complex, Sinai (Egypt): Implications for the Tectonostratigraphic Framework of the Northern Arabian–Nubian Shield

The Sa''al Metamorphic Complex (SMC; southern Sinai) encompasses the oldest arc rocks in the Arabian–Nubian Shield, comprising two non-consanguineous metavolcanic successions (the Agramiya Group and the Post-Ra''ayan Formation) separated by the metasediments of the Ra''ayan Formation. It experienced three distinct deformational events (D1–D3) and two low-medium grade regional metamorphic events (M1–M2). The Agramiya Group and the Ra''ayan Formation experienced all tectonometamorphic events (D1–D3 and M1–M2), whereas the Post-Ra''ayan volcanic rocks were only affected by the D3 and M2 events. D1 is an extensional event and is connected to the late Rodinia break-up (~Tonian; 900–870 Ma). The M1 metamorphism variably affected the older Agramiya Group, the rhyolitic tuffs experiencing lower to upper greenschist facies conditions and the basic and intermediate volcanic rocks undergoing amphibolite facies metamorphism. The Ra''ayan Formation metasediments experienced upper greenschist to amphibolite facies metamorphism. The upper greenschist facies M2 affected the youngest Post-Ra''ayan volcanic rocks and other stratigraphic successions. The compressive D2 and D3 events were coeval with the accretion of dismembered terranes in the assembly of Gondwana. D2 can be linked to the Tonian–Cryogenian arc-arc assembly (~880–760 Ma; in Elat and Sinai), whereas D3 and the accompanying M2 is constrained to 622–600 Ma (Ediacaran).