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Abstract A method was developed for allocating an area likely to be shared by a raingauge station. Average areal precipitation was found by weighting the rainfall at the gauging station in terms of the product of distances enclosing it or radiating from it. The method was applied to two real and two hypothetical basins and the results were compared with those obtained by existing techniques. 相似文献
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A petrographic study of 157 samples from the Early to Middle Eocene deep-marine sandy systems, Ainsa–Jaca basin, Spanish Pyrenees, shows that each system has a characteristic petrofacies. Three main petrofacies are recognized. Petrofacies 1 sandstones comprise mainly siliciclastic grains (≥80%), subordinate terrigenous carbonate grains and negligible intrabasinal grains. Petrofacies 2 hybrid arenites are characterized by significant amounts (≥10%) of intrabasinal carbonate grains. Petrofacies 3 calcilithites contain relatively abundant (≥10%) extrabasinal carbonate grains. On the basis of these petrofacies, a revised correlation of the sandy systems is proposed between the more proximal Ainsa basin, and the more distal Jaca basin sediments, now separated by the Boltaña anticline, across which it is impossible to actually trace out individual beds or sandstone packages between both basins. The arenite composition in the Ainsa and Jaca basins is interpreted as being controlled mainly by synsedimentary tectonic processes that led to changes in sediment sources during basin evolution. 相似文献
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Abstract Some commonly used statistical distributions have been compared to find their applicability for describing minimum flows of the Tigris River at Baghdad gauging station. Drought flows with given return period have, thereafter, been predicted by these techniques. The mean of the estimated flows by the various distributions has been calculated to represent a design drought; upper and lower values estimated have been used to give an idea of variation in drought flow estimation. The methodology suggested herein may avoid the dilemma as to which distribution to select for drought flow estimation. 相似文献
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Abstract Gumbel's method has been simplified in such a manner that one can obtain the magnitude of a given return period flood without recourse to looking at a table and working out the value of the coefficient of variation of the given data. The results obtained by the simplified version are compared with those obtained from using both the original approach and those from Powell's modification of Gumbel's method. 相似文献
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