摘要:

A variety of geophysical records are examined to determine the dependence upon the lagsof a quantity called ‘rescaled range,’ denoted byR(t,s)/S(t,s). If there had been no appreciable dependence between two values of the record at very distant points in time, the ratioR/Swould have been proportional tos0.5. But, in fact, as first noted by Edwin Hurst, theR/Sratio of hydrological and other geophysical records is proportional tosHwithH≠ 0.5. Hurst's original claims must be tightened and hedged, and his estimates ofHmust be discarded, but his general idea will be shown to be correct. We have shown elsewhere that this behavior ofR/Smeans that the strength of long‐range statistical dependence in geophysical records is consi

ISSN:0043-1397    

DOI:10.1029/WR005i002p00321

年代:1969

数据来源: WILEY

摘要:

Sensitivity analysis should be an integral part of nearly every hydrologic study. At an elementary level, sensitivity analysis is useful in studying the relative sensitivity of the result to the data input. Studying the sensitivity of a hydrologic system to changes in its parameters and initial conditions makes it possible not only to gain insight into a system's behavior but to derive simple computational algorithms for the identification of unknown parameters. The fact that sensitivity analysis leads to simple initial‐value problems makes it ideal for mechanization on an analog computer. The computational steps involved in implementing identification algorithms based on sensitivity analysis are relatively simpler than those based on such other methods as quasilinearization. The applicability of this method to identify both lumped and distributed hydrologic systems with deterministic or statistical input‐output data is demonstra

ISSN:0043-1397    

DOI:10.1029/WR005i002p00341

年代:1969

数据来源: WILEY

摘要:

Based on a theoretical model that studies how individuals respond to a commodity uncertain in supply, this paper estimates some demand functions for water in situations where supplies are known to be stochastic. The model is applied to data consisting of a sample of Massachusetts towns, separate functions being estimated for household and industrial demand. Two cross sections are estimated, one for 1962 and one for 1965, the beginning and the end, respectively, of the New England drought.As far as household demand is concerned, price, uncertainty as measured by supply variance, and particularly housing space are significant, whereas for industrial demand only the first two variables are significant. The results also indicate that firms are more responsive than households to both price and uncertainty and that their response to uncertainty lessened as a result of the drought, an implication that agrees with the theoretical model.

ISSN:0043-1397    

DOI:10.1029/WR005i002p00350

年代:1969

数据来源: WILEY

摘要:

A procedure is given for analyzing multisite upland reservoir storage for water supply at a downstream point. Synthetic monthly streamflow for six sites replicates mean, standard deviation, and lag correlation coefficient of historic data; a matrix of spatial correlations interrelates the sites. Factors translate flow to seven reservoirs operated in two modes and one use point. The Thomas‐Fiering formula, using lag‐one correlation and coefficient of variation of historic daily flows and a random gamma variable, converts monthly flow to daily supply at the use point. Results comprise probabilistic analyses of deficiencies and reservoir performances. Results of a study of the Washington, D. C., requirements for 1985 indicate that six upland reservoirs reduce the duration of a deficiency occurring once in a hundred years and that a smaller volume of nearby storage is an alternative or can be used for standby. Results indicate that sophisticated operation of upstream reservoirs should enhance recreational values while concurrently satisfying supply requirements at Washing

ISSN:0043-1397    

DOI:10.1029/WR005i002p00362

年代:1969

数据来源: WILEY

摘要:

Measurements ofZoand other aerodynamic qualities of three crops in Germany (pine forest, lucerne, potatoes) are combined with British records and with those of Tanner and Pelton, permitting the following generalizations. For pliable agricultural crops the roughness length decreases with increasing wind speed (to ½ for 1 to 3 m sec−1), and in this range,Zo≅ crop height/10. Calculations of eddy conductivity (1/ra) give values 3 times that of open water for the farm crops, and 30 times that of open water for the trees. From measured components of the energy balance the surface resistances of the crops are calculated using Monteith's empirical relation. Values ofrsfor the trees‐between 1.0 and 1.5 sec cm−1‐ are always 2 to 4 times as great as for the farm crops, indicating very effective stomatal control of transpiration by pine leaves. Including the two specific crop parameters in Penman's combination formula gives estimates of evaporation for open water, pine forest, potatoes, and lucerne that agree within 5–15% with measurements in southern England and i

ISSN:0043-1397    

DOI:10.1029/WR005i002p00380

年代:1969

数据来源: WILEY

摘要:

The role played by capillary‐gravity waves on evaporation through monolayers was studied for waves in the 400 to 800 cpm range. Waves were generated in a small ripple tank during steady‐state evaporation. Concentrations ofn‐hexadecanol ranging from. 0 to 26.56 × 10−10moles/cm2were studied. The waves destroyed much of the evaporation‐retarding properties o

ISSN:0043-1397    

DOI:10.1029/WR005i002p00395

年代:1969

数据来源: WILEY

摘要:

Heated water was cooled rapidly to impact temperatures that produce optimum growth in plants by applying the water with a standard irrigation sprinkler. Maximum cooling was observed nearest the sprinkler, where the smallest droplets were measured, and temperatures and mean diameters generally increased with distance from the source. Impact temperatures of the water droplets approached but did not reach wet bulb temperatures. Water as hot as 50°C was cooled to droplet temperatures of 25°C or less when the sprinklers were operated in an associated arid climate and at line pressures greater than 25 psi. A theoretical treatment correlated well with one selected set of experimental data and with predicted cooling rates for specified droplets in several typical atmospheric conditions and one untypical condition for an arid climate. Only under the condition of high relative humidity at a given ambient temperature does it appear that cooling might be insufficient to produce usable sprinkler water from 50°C supply water for crop producti

ISSN:0043-1397    

DOI:10.1029/WR005i002p00401

年代:1969

数据来源: WILEY

摘要:

A 0.001 M spray of phenylmercuric acetate was applied by helicopter to part of an aspen stand in northern Utah in June, 1967. The natural fluttering action of the aspen leaves facilitated delivery of the spray to the stomate‐bearing underside of the leaves. Nine days after treatment, stomate width on treated trees averaged 2.4 μ as compared with 4.0 μ measured on untreated trees. Heat pulse measurements indicated reduction in daylight sap velocity from 11 cm/hr to 6 cm/hr. Seasonal soil moisture depletion was not significantly affected, although the pattern of water usage was delayed for about 6 weeks on the treated a

ISSN:0043-1397    

DOI:10.1029/WR005i002p00407

年代:1969

数据来源: WILEY

摘要:

Water Planning for Israel is conducting field tests to determine the feasibility of applying long‐chain alcohols on the Sea of Galilee for evaporation reduction. Good film covers have been obtained on 280‐acre Lake Zohar with winds up to 15 mph, and a spray system is being installed on Lake Kishon to test a larger lake with stronger prevailing winds. Using meteorological data and estimated evaporation rates for the Sea of Galilee, the reduced evaporation when covered with an alcohol film has been calculated from the added film resistance. The iterative solution of an energy balance equating the reduced evaporation energy to increased energy storage, back radiation, and conduction to the atmosphere gave a 40% reduction of the annual evaporation rate of 300 million cubic meters when applying a film for a 10‐month period. The film produces a maximum temperature increase of 5°C at the s

ISSN:0043-1397    

DOI:10.1029/WR005i002p00413

年代:1969

数据来源: WILEY

摘要:

Simple linear regression models for predicting total volume of runoff, peak rate of runoff, duration of runoff, and hydrograph lag‐time were developed using three years of data from four small (0.56 to 11.0 acres) watersheds. The models developed indicated that runoff volume was most strongly correlated to total precipitation; that peak rate of runoff was most strongly correlated to the maximum 15‐minute depth of precipitation; that flow duration was most strongly correlated to watershed length; and that lag time was most strongly correlated to watershed area. These independent variables accounted for 70, 70, 50, and 30%, respectively, of the variance in the predicted variables. The exponential decay form of the antecedent precipitation equation accounted for 8% of the variation in runoff on one watershed but was insignificant on the others. Analysis indicates that the data represent the high frequency events. It is possible that these models will not accurately predict the low frequency eve

ISSN:0043-1397    

DOI:10.1029/WR005i002p00419

年代:1969

数据来源: WILEY