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N.C. Matalas

Publications and source records attributed to N.C. Matalas.

14 recordsLinked to original sources
USGS2011

Water resources of the People's Republic of China

At the invitation of the Society of Hydraulic Engineers of the People's Republic of China (PRC), a delegation of U.S. hydrologists and hydraulic engineers visited the PRC in the fall of 1978.* From discussions with officials of both the Society and the Ministry of Water Conservancy and Power (MWCP), and from visits to research and academic institutions and water projects, the delegation gained a general understanding of the country's surface water resources. The reported statistics, supplemented with others from published sources, provide a quantitative description of the PRC's water resources in relation to those of the United States.

Eos, Transactions, American Geophysical Union↗
USGS2010

Probability weighted moments compared with some traditional techniques in estimating Gumbel Parameters and quantiles

Estimates of the parameters and quantiles of the Gumbel distribution by the methods of probability weighted moments, (conventional) moments, and maximum likelihood were compared. Results were derived from Monte Carlo experiments by using both independent and serially correlated Gumbel numbers. The method of probability weighted moments was seen to compare favorably with the other two techniques.

Water Resources Research↗
USGS2010

Quantile estimation with more or less floodlike distributions

The desirable properties of an estimator relative to a hypothetical population may be irrelevant in practice unless the population at issue more or less resembles the hypothetical population. Evidence that floods are distributed with long, stretched upper tails suggests that use of the more common distributions results in a rather precise underestimation of the extreme quantiles and thereby in the underdesign of flood protection measures.

Water Resources Research↗
USGS2010

Note on the applicability of the James-Stein Estimator in regional hydrologic studies

The applicability of the James-Stein estimator in regional hydrologic studies which entail the estimation of an N -dimensional location parameter is discussed. Regional studies are frequently characterized by relatively short, generally correlated, samples drawn from nonsymmetric and bounded, i.e., nonnormal, populations. By means of computer simulation studies the James-Stein estimator, subject to the Lindley modification and adoption of the positive part rule suggested by Efron and Morris and conditioned on the assumption of independence, was shown to be robust in the case of the hydrologically plausible distribution considered here, namely, Weibull distributions with coefficient of skewness ranging from 0 to 10. However, in contrast to traditional methods of regionalization the effect of cross correlation is a diminishment of the relative risk advantage of the James-Stein estimator, even in the best case of normal variables : this is discussed and illustrated.

Water Resources Research↗
USGS1991

Drought description

What constitutes a comprehensive description of drought, a description forming a basis for answering why a drought occurred is outlined. The description entails two aspects that are "naturally" coupled, named physical and economic, and treats the set of hydrologic measures of droughts in terms of their multivariate distribution, rather than in terms of a collection of the marginal distributions. ?? 1991 Springer-Verlag.

Stochastic Hydrology and Hydraulics↗
USGS1986

On the nature of persistence in dendrochronologic records with implications for hydrology

Hydrologic processes are generally held to be persistent and not secularly independent. Impetus for this view was given by Hurst in his work which dealt with properties of the rescaled range of many types of long geophysical records, in particular dendrochronologic records, in addition to hydrologic records. Mandelbrot introduced an infinite memory stationary process, the fractional Gaussian noise process (F), as an explanation for Hurst's observations. This is in contrast to other explanations which have been predicated on the implicit non-stationarity of the process underlying the construction of the records. In this work, we introduce a stationary finite memory process which arises naturally from a physical concept and show that it can accommodate the persistence structures observed for dendrochronological records more successfully than an F or any other of a family of related processes examined herein. Further, some question arises as to the empirical plausibility of an F process. Dendrochronologic records are used because they are widely held to be surrogates for records of average hydrologic phenomena and the length of these records allows one to explore questions of stochastic process structure which cannot be explored with great validity in the case of generally much shorter hydrologic records.

Journal of Hydrology↗
USGS1976

Design of a ground-water level observation network

In January 1971, a cooperative study was initiated by the Hydrological Service of Israel and the U.S. Geological Survey to develop concepts and systems analytic techniques for the design of ground water data collection systems with the objective of providing hydrologic information for planning and managing water resource systems. This report summarizes the results of the study which was completed in January 1972. While some of the results pertain specifically to the data program of the Hydrological Service of Israel, the analytic techniques of design developed in the course of this study are quite general and by no means restricted to problems in Israel. Because of the statistical orientation of the study and the fact that the analytic design techniques are not dependent upon the dynamic characteristics of ground water, the techniques are, with appropriate modification, applicable to the design of other types of hydrologic data collection systems.

Open-File Report↗
USGS1964

A correlation procedure for augmenting hydrologic data

A linear regression for a short and long sequence of hydrologic events is used to lengthen the short sequence. The lengthened sequence consists of the original observations and regressed values plus noise, where the noise is a random variable with zero mean and variance proportional to the variance of the observations for the short sequence about the line of regression. Estimates of the mean and variance for the lengthened sequence are shown to be unbiased. If the correlation coefficient, which measures the strength of the linear regression, exceeds about 0.5, then the estimates of the mean and variance based on the lengthened sequence are better estimators of the population values of the mean and variance than the estimates based on the observations for the short sequence. If noise is not added to the regressed values, the correlation coefficient must exceed about 0.8 to obtain improvement in the estimates by use of correlated values.

Professional Paper↗
USGS1963

Autocorrelation of rainfall and streamflow minimums

Hydrologic time series of annual minimum mean monthly rainfall and annual minimum 1-day and 7-day discharge, considered as drought indices, were used to study the distribution of droughts with respect to time. The rainfall data were found to be nearly random. The discharge data, however, were found to be nonrandomly distributed in time and generated by a first-order Markov process. The expected value of the variance for a time series generated by a first-order Markov process was compared with the expected value of the variance for a random time series. This comparison showed that the expected value of the variance for a nonrandom time series converged to the population variance with an increase in sample size at a slower rate than for a random time series.

Professional Paper↗
USGS1962

Statistical properties of tree ring data

A statistical analysis is made of the sequences of annual tree ring widths and indices. The expected value of growth during any year is shown to be proportional to the standard deviation of the growth, so that the coefficient of variation is a measure of the sensitivity of the growth of a tree . Tree ring data were found to be non-randomly distributed in time. The large values of serial correlation indicated that the non-randomness cannot be attributed entirely to climatic factors. Correlogram and power spectrum analyses applied to a sequence of tree ring indices for a pinyon pine showed that the data were generated by an autoregressive process. The statistical parameter measuring the sensitivity or complacency of growth is used to derive a growth function.

International Association of Scientific Hydrology ↗