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Summary ?One of the most important features in analysing the climatology of any region is to study the precipitation and its periodicity
of different harmonics in order to study the behavior of the observed data. In this study the amplitude of frequencies, phase
angle and basic statistical parameters are calculated in order to depict spatial characteristics of precipitation over Jordan.
Precipitation records of 17 stations were chosen according to climatic regions of Jordan. The first and second harmonic analyses
explain more than 90% of the precipitation variation in Jordan effectively. The amplitudes of the first and second harmonic
were calculated in order to describe the climatic regions in the country. The maximum amplitudes were found in the northern
mountainous region. The phase angle representing the time of maximum rainfall is also used in the form of a contour chart.
It is found that Jordan has its main rainfall season in winter with maximum around January. The coefficient of variation shows
the high variability of rainfall of the country.
Received February 4, 2002; revised August 1, 2002; accepted August 6, 2002 相似文献
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Q. Y. Tarawneh M. El Alfy 《International Journal of Environmental Science and Technology》2017,14(6):1267-1276
Saudi Arabia is a huge area with diverse climatic and topographical features. This diversity in climate is augmented by seasonal weather variations. The study discusses solar irradiance and sunshine duration in terms of seasonal weather systems. Sunshine duration and solar irradiance maps show that the East Mediterranean weather systems (such as Cyprus low) in winter affect the majority of the geographical regions in Saudi Arabia. In spring and autumn, Sudan low becomes more active than Cyprus low, especially in the west and central regions. Sunshine duration in April is 47% compared to 50% in January. Sunshine duration in the southwest region is affected by the rainy and wet summer monsoon which reduces sunshine duration to 33% in summer (July), while it is 43% in winter (January). In addition, the study uses the Angstrom equation to estimate solar irradiance. The absolute relative error between estimated and observed solar irradiance ranges between 2 and 10% in the majority of cases, with a few cases exceeding 13%. 相似文献
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A hydrological record extension model for reconstructing streamflows from tree‐ring chronologies 
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下载免费PDF全文 Characterizing drought events is an important factor in designing and operating water resource projects, but instrumental hydrologic records are generally short (<100 years). Because estimates of drought statistics can improve when longer records are available, we developed a stochastic model to extend instrumental streamflows based on tree‐ring chronologies. This Record Extension plus Noise (or REXTN) model consists of an autoregressive term to account for the temporal persistence of streamflows, predictor variables with longer records, and a noise term. The noise term was included to avoid underestimating the variability of the flows and to generate multiple extensions, which offer the possibility of quantifying the uncertainty of drought statistics such as the critical drought. For cases where having multiple extensions is not desirable, a statistically based algorithm was developed to select a single extended record. Using a simulation experiment, model REXTN was found to perform better than other existing reconstruction methods. The model was then applied to extend streamflows of the Poudre River, CO, USA, based on tree ring‐chronologies back to the year 1600, and the reconstructions were used to determine drought statistics such as duration and magnitude. When results based on the classical linear regression model were compared with those calculated by model REXTN, the latter was found to better match flow and drought statistics from the instrumental records, as well as to give a broader range of drought duration and magnitude. The REXTN model provides a useful addition to the range of tools available to hydrologists for coping with the uncertainty associated with water resource management under future climate scenarios. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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Bashar Tarawneh 《地学前缘(英文版)》2017,8(1):199-204
Standard Penetration Test(SPT) and Cone Penetration Test(CPT) are the most frequently used field tests to estimate soil parameters for geotechnical analysis and design.Numerous soil parameters are related to the SPT N-value.In contrast,CPT is becoming more popular for site investigation and geotechnical design.Correlation of CPT data with SPT N-value is very beneficial since most of the field parameters are related to SPT N-values.A back-propagation artificial neural network(ANN) model was developed to predict the N6o-value from CPT data.Data used in this study consisted of 109 CPT-SPT pairs for sand,sandy silt,and silty sand soils.The ANN model input variables are:CPT tip resistance(q_c),effective vertical stress(σ'_v),and CPT sleeve friction(f_s).A different set of SPT-CPT data was used to check the reliability of the developed ANN model.It was shown that ANN model either under-predicted the N_(60)-value by 7-16%or over-predicted it by 7-20%.It is concluded that back-propagation neural networks is a good tool to predict N_(60)-value from CPT data with acceptable accuracy. 相似文献
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This study is concerned with the spatial variability of some wet atmospheric precipitation parameters such as; pH, conductivity (EC). The study also depicts the spatial variability of some ions (cations and anions) of atmospheric precipitation in Jordan such as, Ca2+, Mg2+, Na+ and K+, HCO3−, Cl−, NO3− and SO42−. The basis of the work is to establish a relationship through the cumulative semivariogram technique between the distance ratios and the spatial dependence structure of the chemical composition of atmospheric precipitation. All semivariogram models are constructed in this study in order to understand the behavior of the spatial distribution. The spatial distributions of rainwater parameters show differences from station to station which is expressed in terms of angle, where the larger the angle the weaker the correlation. The semivariogram (SV) models are constructed to show the variation of the rainfall chemistry in Jordan. The SV models show weak correlation between mountain and leeside mountain stations, i.e. mountain and desert stations. On the other hand, good correlations are observed when transferring from south to north of the country. The larger is the found angle, the weaker is the correlation. For most of the SV model the correlation is found to be very weak between desert and mountainous locality. The Standard Regional Dependence Factor (SRDF) is used for prediction of the distribution of rain fall parameters. It shows the relative error between observed and predicted values of rainwater parameters. The overall regional relative error between the observed and estimated concentrations remains less than 15%. 相似文献
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Petrography, chemistry and genesis of phosphorite concretions in the Eocene Umm Rijam Chert limestone Formation, Ma'an area, south Jordan 总被引：1，自引：0，他引：1
Phosphorite concretions are recorded for the first time within the lower part of the Umm Rijam Chert Limestone Formation (Eocene) in the Ma'an area, southern Jordan. The phosphorite concretions are typically hosted and encountered as individual layer in moderately lithified sediments of marl, chalk and chalky marl. The phosphorite concretions are present in thin layer (10–30 cm thick). They are localized on a hardground surface that formed as a result of cementation of soft ground by bioclastic materials. Light grey and brownish to black colors are encountered with isometric, ellipsoid, elongated, subangular to subrounded phosphorite concretions (up to 6 cm in length). Most of the phosphorite concretions preserve bioturbation structures; they also include fecal pellets of various sizes. The main biogenic components are fragments of macrofossils (bivalves) and microfossils (planktonic foraminifera) in different proportions. Petrographic examinations reveal that the phosphorite concretions are composed of cryptocrystalline apatite that characteristically appears in cross-polarized light almost as isotropic phosphate and minor anisotropic phosphate. Apatite and calcite are the main mineral constituents of the phosphorite concretions identified by XRD. The apatite is identified as francolite (carbonate-flour-apatite). Chemical analyses of the phosphorite concretions using X-ray florescence indicate that the P2O5 content ranges from 18.8 to 31.19%, whereas SEM–EDS analyses indicate that the phosphorus proportion is around 14% by volume. It could be argued that the phosphorite concretions were transported after being reworked, or were derived from carbonate and chalk pebbles that were later phosphatized and subjected to erosion, forming residual lag deposit along the hardground surface. 相似文献
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The Dead Sea is worldwide a major bromine provider for industry with an average concentration of 5.2 g/l of bromide compared to 0.065 mg/l in seawater and with a Cl/Br weight ratio in the Dead Sea water of about 42 compared to around 300 in oceanic water. The origin of the high bromide concentration in the Dead Sea has not yet been adequately clarified. In the course of this study, the bromide concentrations in the different surface and groundwater bodies in Jordan were analyzed and the types of rocks with which these waters were in contact were identified. Analyses carried out up to about 30 years ago and recent analyses confirm the natural origin of bromide in the water and also confirm that the analyzed sources are not polluted by anthropogenic bromide sources. It was found that a variety of these surface and groundwater sources contain high concentrations of bromide which discharges into the Dead Sea and contribute to its high bromide concentration. The present study concludes that the late Cretaceous early Tertiary oil shale deposits form the major source of the bromine species in the surface and groundwater feeding the Dead Sea. Some bromide is also contributed by the Triassic and Jurassic rocks containing evaporate salts containing bromides. Phosphate rocks of late Upper Cretaceous age contribute also with appreciable amounts of bromine species to the different water sources and hence to the Dead Sea water. At present, dissolution and erosion of bromide-rich sediments laid down by the predecessor water bodies of the present Dead Sea such as the Lisan Lake are being transported into the Dead Sea and contribute relatively large amounts of secondary bromide to the Dead Sea water. 相似文献