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Abstract Flood distributions can have unimodal or multimodal densities due to different flood generation mechanisms such as snowmelt and rainfall in the annual flood series. When applying nonparametric frequency analysis to annual flood data from the province of New Brunswick in Canada, unimodal, bimodal and heavy-tailed distribution shapes were found. By grouping basins with similarly-shaped densities on a geographical basis, homogeneous regions were delineated. Regional equations derived for a homogeneous region gave lower integral square errors than those of province-wide equations. 相似文献
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ABSTRACT Time series techniques were employed to determine rates of vertical crustal movement within the Great Lakes region of North America. Observations of water level elevations as recorded at gauges around the lakes, and differences in elevations between pairs of gauges were analysed for linear trends, periodicities and stochastic components. It was found that the variance of time series of elevations consisted mainly of first-order linear trends and small periodic components. Relative rates of crustal movement were computed from a linear trends analysis of elevation differences. These rates were converted to absolute rates of movement using the Nipissing zero isobase as a datum. This study shows that, in general, the northeastern area of the Great Lakes region is rising at a rate of about 1·00 ft per 100 years relative to the southwest of the region. 相似文献
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LESZEK LINDNER LESZEK MARKS KAZIMIERZ PEKALA 《Boreas: An International Journal of Quaternary Research》1984,13(1):35-47
On the basis of field and laboratory studies supported by thermoluminescence dates, an occurrence of marine and glacial sediments is described from South Spitsbergen. These deposits are thought to date from the Holsteinian interglacial and the Saalian glacial stages respectively. In addition, the evidence and extent of Vistulian and Holoccne glacial advances in South Spitsbergen are presented. These advances occurred at 50,000–43,000, 30,000–10,000, 3,000–2,500 and 600–100 years B.P. The latter have been tentatively correlated with those recorded in other parts of Svalbard, as well as in East Greenland, the Barents Sea, Scandinavia, the Baltic Sea, North Poland and the Russian Plain. 相似文献
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KAZIMIERZ WIIKOWSKI 《Boreas: An International Journal of Quaternary Research》1989,18(4):357-358
A new simple method of using a stretching device to stabilize coring rods in deep water is described. The method can be used for sediment coring with rod-operated samplers in lakes of a water depth down to 30–40 m. 相似文献
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Six-year record of atmospheric carbon dioxide and methane at a high-altitude mountain site in Poland 总被引:2,自引:0,他引:2
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Abstract The natural variability of precipitation in agricultural regions both in time and space is modelled using extensions of Box & Jenkins (1976) methodology based on the ARMA procedure. This broad class of aggregate regional models belongs to the general family of Space-Time Autoregressive Moving Average (STARMA) processes. The paper develops a three-stage iterative procedure for building a ST ARMA model of multiple precipitation series. The identified model is STMA (13). The emphasis is placed on the three stages of the model building procedure, namely identification, parameter estimation and diagnostic checking. In the parameter estimation stage the polytope (or simplex) method and three further classical nonlinear optimization algorithms are used, namely two conjugate gradient methods and a quasi-Newton method. The polytope method has been adopted and the developed model performed well in describing the spatio-temporal characteristics of the multiple precipitation series. Application has been attempted in a rural watershed in southern Canada. 相似文献
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