ISSN:0303-6936    

DOI:10.1080/02626667409493862

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

ISSN:0303-6936    

DOI:10.1080/02626667409493863

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

ISSN:0303-6936    

DOI:10.1080/02626667409493864

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

ISSN:0303-6936    

DOI:10.1080/02626667409493865

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Errors in the statistical estimation of the correlation and phase between the periodic components of two concurrent time series arising from inadequate sampling are investigated. Analytically developed concepts of aliasing errors are applied to spectra of simple analytical form as well as to more complex geophysical time series. The errors introduced by inadequate sampling into the spectra of four periodic events are amply demonstrated by the observations. For correlated oscillations coherences are reduced, phases are shifted, and spectral peaks are broadened. The theory allows a quantitative account of aliasing when applied to an ensemble average of aliased spectra. An interesting effect of aliasing resulting in the splitting of spectral lines cannot be quantitatively accounted for due to nonstationarity of the random process. It is recommended that if interest is centred in periods of water level fluctuation less than the semidiurnal period then unaliased water level readings should be employed in spectral computations.

ISSN:0303-6936    

DOI:10.1080/02626667409493866

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Steady-state concentration in lake water is determined by the rate of input, residence time of water, and rate of removal into lake floor sediments. For a given input (loading) rate, a steady-state concentration is a ‘warning sign’ or a limit to which the lake will tend. For 22 lakes in North America and Western Europe, the upper limits of steady-state concentrations of phosphorus are in the ‘eutrophic’ range from 0·03 to 0·3 mg P/l., at the existing input rates of 10−2to 10−1mg 1.−1year−1. A natural baseline input of phosphorus to lakes, owing to the chemical weathering of continents, is lower, 10−4to 10−3mg 1.−1year−1. The rates of removal of phosphorus to lake floor sediments are of the order of 25–50 per cent of input load. For sodium and chloride, mean rate of removal into sediment is less than 0·5 per cent of input load; for Sr90, 1–4 per cent; and for Cs137, 25–65 per cent or higher. The higher rates of removal into sediments result in lower concentration in lake water.

ISSN:0303-6936    

DOI:10.1080/02626667409493867

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

This report describes an analytical approach to the problem of defining changes in the water levels of two lakes or reservoirs connected by a channel subjected to flow blockages or retardations due to ice. Routing equations for this purpose were derived for Lakes Michigan-Huron and Erie which form a portion of the Great Lakes system. Procedures were developed for computing the monthly winter flow retardation due to ice in the St. Clair River, the outlet channel for Lake Michigan-Huron. An examination of these flow retardations, 1899–1969, indicated that the degree of retardation has progressively diminished since 1920. Utilizing the routing equations derived, the effects of these reductions in the retardations were computed to have lowered the levels of Lake Michigan-Huron by 0·50 ft. Investigation of factors responsible for the reduction in the winter flow retardations lead to the conclusion that the major factor was man-made channel enlargements in the St. Clair River.

ISSN:0303-6936    

DOI:10.1080/02626667409493868

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

In Norway, most water power projects cause increased winter flow in the rivers and through the lakes. This paper deals with some aspects of the changes in temperature distribution in, and ice conditions on the lakes, when subject to increased winter flow. The main factors which affect ice conditions in lakes, are the temperature and rate of the inflowing water. Experiences from several Norwegian lakes show some unexpected, but rather interesting results, especially when the inflowing water has a high temperature, which in this connection means 1–3 °C.

ISSN:0303-6936    

DOI:10.1080/02626667409493869

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

ISSN:0303-6936    

DOI:10.1080/02626667409493870

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

ISSN:0303-6936    

DOI:10.1080/02626667409493871

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor