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1.
Amazonia I is a large multi-disciplinary project, now in its fourth year, concerned with the effects of changing land use on the ecology and climate of the Brazilian Amazon. It is primarily concerned with investigating the water, carbon and nutrient cycles, and brings together about 80 scientists from a number of Brasilian institutes, but especially from INPA in Manaus, CENA/USP in Piracicaba and EMBRAPA/CPATU in Belem.Major activities include the better identification of water vapour producing precipitation, to establish better water vapour circulation models (via 18O, deuterium and 3H analysis, plus radiosonding); the study of water relations of isolated forest areas; the study of various phases of the carbon cycle especially soil organic matter; primary production; and nitrogen and soil fertility studies.A first phase Regional Amazon Model (RAM) for hydrology is being developed, and it should shortly be possible to make a first research-based attempt at modelling the carbon cycle of the Amazon region.This coordinated project represents in most ways the type of research required for the International Geosphere-Biosphere Programme (IGBP) and is a major Brasilian initiative.  相似文献   

2.
Barth  Hans Karl  Quiel  Friedrich 《GeoJournal》1986,13(3):251-259
Due to a particularly favourable geologic and tectonic setting in the Eastern Province, Saudi Arabia has the world largest oil reserves and is the third largest oil-producing nation in the world. Based on oil and gas revenues, the Kingdom experienced an overwhelming development during the last few decades, changing a desert country into a modern industrialized nation. Main characteristics of spatial changes are based on processes of urbanization and industrialization, on agricultural reclamations and infra-structural developments. Since the natural environment of deserts and semi-deserts in the Eastern Province is determined by an extremely sensitive equilibrium, environmental impacts, shortages in water resources, as well as limited human resources are causing basic problems, which will influence future developments.  相似文献   

3.
Al-gabbani M 《GeoJournal》1992,24(4):375-385
"This paper examines and assesses the changes in the population density pattern in the city of Riyadh, the capital of Saudi Arabia where the city has undergone dramatic changes in its physical as well as its social structure. Analysis of data revealed a decline in population density at an exponential rate from the city center with variation between city sectors and zones. The city's rapid horizontal expansion and dispersal of population is the result of factors such as increases in city population and in size and number of single family dwellings, widening of streets, rise in income and residential mobility rates, mass use of automobiles, change in family size, zoning regulations, leapfrogging, and huge governmental city development projects."  相似文献   

4.
This paper examines and assesses changes in the population density pattern in the city of Riyadh, the capital of Saudi Arabia where the city has undergone dramatic changes in its physical as well as its social structure. Analysis of data revealed a decline in population density at an exponential rate from the city center with variation between city sectors and zones. The city's rapid horizontal expansion and dispersal of population is the result of factors such as increases in city population and in size and number of single family dwellings, widing of streets, rise in income and residential mobility rates, mass use of automobile, change in family size, zoning regulations, leapfrogging, and huge governmental city development projects. The resulting low population density pattern made it difficult for city officials to provide necessary services and facilities for the dispersed residential development. This paper recommends that city officials make real efforts and workable programs to stop or slow this uneconomical growth by improving quality of life in the central areas to make them residentially desirable by some city residents and reduce the high residential turnover the central area has experienced in last years, and to centralize peripheral growth by planning for self-sufficient satellite communities in outer areas.  相似文献   

5.
In central Saudi Arabia, the combination of rock types and sedimentary bedding created a unique scarp landscape. The escarpments were formed during Late Miocene through Early Quaternary times. At present, cuesta formation and migration are restricted to the actual escarpments as a consequence of negligible sediment removal. The plains between the escarpments are sealed through periodically active fluvial processes and through eolian sedimentation. In this publication, the major escarpments of central Saudi Arabia are described. The interactions between tectonics, climate, and morphogenesis which created this unique landscape are reviewed.  相似文献   

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The extent of desertification on Saudi Arabia   总被引:2,自引:0,他引:2  
Desertification is the process that turns productive deserts into non-productive deserts as a result of poor land-management. Desertification reduces the ability of land to support life, affecting wild species, domestic animals, agricultural crops and humans. The reduction in plant cover that accompanies desertification leads to accelerated soil erosion by wind and water. South Africa is losing approximately 300–400 million tons of topsoil every year. As vegetation cover and soil layer are reduced, rain fall impact and run-off increases. This paper discusses the extent of desertification, its potential threat to sustained irrigated agriculture and possible measures adopted to control ongoing desertification processes to minimize the loss of agricultural productivity in an arid country such as the Kingdom of Saudi Arabia.  相似文献   

9.
This paper examines the distribution characteristics of urban settlements in the Kingdom of Saudi Arabia through major dimensions such as settlement regularly, degree of primacy and polarisation at the national and geographic regional levels. The paper points out that the settlement pattern at the national level has transformed from a primate distribution during the pre-plan period (< 1970) to an intermediary distribution during the period of development planning (1970 >). At the geographical regional level the settlement distribution, however, has shown diverse pattern. While the regional settlement distribution of Western and Eastern Region have shown trends of increasing polarisation, settlements in the Northern and Southern Regions are more log-normal in character. This is explained by the increasing growth of small and intermediary towns in the Northern and Southern Regions. The paper concludes that the national trend of decreasing urban primacy, induced by the decentralised national development strategies, is less pronounced due to the absence of a balanced regional investment policy. Since the government expenditure and settlement population growth rates are not related, slow growing primate cities continue to receive a larger share of public expenditure, enabling them to retain their primacy. This calls for a balanced regional investment policy to fully realise the national strategy of regional balance and multi-polar settlement pattern.  相似文献   

10.
The developmental schemes implemented by the Government in the Al-Hassa Oasis have influenced the social and economic behavior of Al-Hassa farming community. The impact of these socio-economic changes on agricultural practices and water use have been evaluated in this study.A detailed questionnaire was prepared considering social attitude, standard of living, family structure, and occupation, and was distributed among the farmers of the Al-Omran area. Data thus collected were statistically evaluated. The study showed that literacy and social exposure were the major factors for the acceptability of modern agricultural practices in the oasis.  相似文献   

11.
Drought and human adjustment in Saudi Arabia   总被引:1,自引:0,他引:1  
Drought is one of the natural hazards which causes death and damage for property particularly in drylands of the world. Drought as a natural hazard tends to limit and disrupt human activities. On the other hand, man has tried to adjust his living conditions to this hazard. The adjustment to drought is different from one country to another. Adjustment to drought is affected by culture, income, and by the political system in the country. In the case of Saudi Arabia adjustment to drought hazard is usually the work of both individuals, and government. The Saudi Arabian government has spent large sums of money to reduce impact of drought hazard.  相似文献   

12.
The porosity and engineering properties of vesicular basalt in Saudi Arabia   总被引:2,自引:0,他引:2  
The presence of non-connected vesicles in extensive basalt flows in western Saudi Arabia greatly affects their engineering properties such as compressive strength, modulus of elasticity, Poisson's ratio and sonic velocities. In order to evaluate some of these properties, the density and/or the porosity of the material must be known. Using conventional methods to determine the porosity or the density of irregular lumps proved to be erroneous. An image analysis technique is suggested to estimate the porosity of the vesicular basalt. The estimated values were correlated against the calculated porosity values using core samples, and were found to have excellent correlation (R=0.99). The estimated porosity values were also correlated against the static and dynamic properties of the basalt and a good level of correlation (R=0.77) was obtained.  相似文献   

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Summary This paper presents a brief review of the geological and geotechnical aspects of the Kingdom of Saudi Arabia. The first part of the paper presents a brief summary of the geological aspects and the soil characteristics in different parts of the country. The second part gives a brief outline of the major geotechnical problems encountered in the regions of the Kingdom along with their geographical locations.  相似文献   

16.
This paper presents the derivation of the design storm hyetograph patterns for the Kingdom of Saudi Arabia based on real rainfall events from meteorological stations distributed throughout the Kingdom. Two thousand twenty-seven rainfall storms for a 20–28-year period were collected and analyzed covering 13 regions of the Kingdom. Four distinct dimensionless rainfall hyetograph patterns have been obtained over the Kingdom, while two patterns have been obtained for each individual region because of the lack of data for long-duration storms in individual regions. The resulting dimensionless rainfall patterns for each region can be used to develop storm hyetographs for any design duration, total rainfall depth and return period. It has been shown that the developed storm hyetographs have different features from other storm patterns that are commonly used in arid zones. The study recommends using these curves for the design of hydraulic structures in Kingdom of Saudi Arabia and regions alike.  相似文献   

17.
The study focuses on the analysis of manufacturing industry in Saudi Arabia by examining development, structure and spatial distribution. The analysis has shown that Saudi manufacturing is basically of recent development and is highly capital- and energy-intensive, particularly the hydrocarbon-based groups. Perhaps the most conspicuous weakness of Saudi industrialization is the almost total dependence on expatriate labour. Foreign capital and expertise share in the building and development of the industrial sector by providing technical, managerial, and marketing skills. Saudi industry is heavily subsidized by the government, and the public sector plays a commanding role in industrial development. Large-scale basic industries are owned and run by the government, while light manufacturing of the import-substitution type is dominated by the private sector. One of the main characteristics of manufacturing industry is that it is scantily diversified, modestly concentrated and remarkably linked geographically but not functionally or structurally. Although the authorities are exerting tremendous efforts to achieve a regional balance in industrial development, Saudi manufacturing industry is significantly polarized, urban-oriented and highly associated with the major axes of population scatter. Like all developing countries beginning to industrialize, Saudi manufacturing industry faces certain problems which have to be resolved so as to lay the foundations for a sound and prosperous industrial future. The paper goes on to indicate problems and to suggest solutions.  相似文献   

18.
Small volumes of peralkaline granites were generated as the final phase of a Pan African calc-alkaline igneous event which built the Arabian Peninsula. The peralkaline granites are closely associated with trends or sutures related to ophiolites. Peralkaline rocks are chemically heterogeneous, with anomalous abundances of Zr (average 2,150 ppm±2,600 1), Y (200±190), and Nb (105±100), representing up to ten-fold enrichments of these elements relative to abundances in calc alkaline granite counterparts. Large enrichments of some rare earth elements and fluorine are also present.The peralkaline granites have scattered whole rock 18O values, averaging 8.7±0.6% in the Hadb Aldyaheen Complex and 10.7±1% in the Jabal Sayid Complex. Quartz-albite fractionations of 0.5 to 1.5% signify that the heavier whole rock -values probably represent the oxygen isotope composition of the peralkaline magma. Small variable enrichments of 18O, in conjunction with slightly elevated 87Sr/86Sr initial ratios relative to broadly contemporaneous calc alkaline granites, are both suggestive of a small degree of involvement of crustal, or crustal derived material in the peralkaline magmas. It is proposed that the peculiar magma genesis is associated with a relaxation event which followed continental collision and underthrusting of salt rich sediments.  相似文献   

19.
Earth Fissuring and Land Subsidence in Western Saudi Arabia   总被引:4,自引:0,他引:4  
The present investigation deals with the engineering geological evaluation of earth fissuring associated with land subsidence in Wadi Al-Yutamah. The investigations include surface mapping and sampling, in situ and laboratory soil testing, water well inventory, geophysical survey, and monitoring of open fissures and the level of the wadi floor.The earth fissures in the area developed as a result of land subsidence due to man-induced water level declines caused by pumping water from the wadi aquifer above a safe yield. This situation has produced a compaction of underlying unconsolidated sediments and formed hair fissures above ridges and steps of buried surface bedrock. These hair fissures enlarged later after flood erosion and possible enhancement with hydrocompaction.The wadi soil in the study area consists mainly of silt of low plasticity, low density and high void ratio and it was classified as loess like material and collapsing soil. The settlement in the area is greatly increased by excessive wetting under constant pressures. The calculated coefficients of subsidence (collapse) show that the wadi soils were considered to pose moderate problems when wetted.Monitoring of the existing open earth fissures using extensometers indicates that the width of the fissure increases after flooding or rain falls. Monitoring of the ground level using GPS techniques, shows a good relation between the declination of the water table and the subsidence of the ground of the wadi floor.  相似文献   

20.
The present paper reviews the conservation movement in Saudi Arabia as measured against the established protected areas, as well as the basic philosophy regarding natural resource management. The degree of representation of the biophysical diversity of Saudi Arabia in the established protected areas is discussed by using three areas as case studies: Harrat Al-Harrah (lava field), Urug Bani Mu'arid (Cuesta and Sand), and Raydah Escarpment (High Mountain).  相似文献   

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