bluuebunny/crossref_metadata_2025 huggingface dataset:
Über die Existenz electrischer Ionen in der Atmosphäre
Authors: Elster Von J. , Geitel H.
Published: February 2008

Die Erfahrungen der letzten Jahrzehnte haben zu einer bestimmten Vorstellung von der Art der Electricitätsleitung in den Gasen geführt. Ein Gasmolekül selbst ist hiernach unfähig eine electrische Ladung anzunehmen und daher auch nicht im Stande eine solche zu übertragen, dagegen kann es durch gewisse Einwirkungen in zwei Teile zerlegt werden, deren einer eine unveränderliche positive, deren anderer die complementäre negative mit sich führt, Ladungen, die enorm viel höher sind, als diejenigen, die den betreffenden Teilchen durch Berührung mit electrisch geladenen Körpern mitgeteilt werden könnten. Diese entgegengesetzt geladenen Bestandteile des Moleküles entsprechen also den Vehikeln des electrischen Stromes bei der Electrolyse, man hat deshalb auf sie dieselbe Bezeichnung “Ionen” angewandt. Es ist gut, sich zu vergegenwärtigen, dass—mindestens für elementare oder gar einatomige Gase—wahrscheinlich aber auch allgemein der Sinn dieses Ausdrucks mit dem für Electrolyte gültigen sich nicht völlig decken kann.
The cause of the Earth's magnetism
Authors: Sutherland William
Published: February 2008

In this Journal for June, 1900, it was shown that a sphere of radius a charged with electricity of volume density ρ, and revolving round an axis with angular velocity Ω, would have a magnetic potential at a point r, θ where θ is the colatitude,

urn:x-wiley:00968013:media:tma3190:tma3190-math-0001
If an equal amount of the opposite sort of electricity were distributed through a sphere of radius a ‐ da, its volume density ρ′ would be determined by the condition,

urn:x-wiley:00968013:media:tma3190:tma3190-math-0002
and its magnetic potential would be,
The magnetic potential of the two distributions together would be
If ρ is assumed to be not a function of R, this becomes

urn:x-wiley:00968013:media:tma3190:tma3190-math-0005
This is the right form of expression for the average magnetic potential round parallels of latitude on the Earth's surface.
Magnetic storm of October 31–November 1, 1903, recorded at the coast and geodetic survey magnetic observatories
Authors: Bauer L. A.
Published: February 2008

As stated in Note 16, p. 188, of volume VIII of this Journal, it had been the intention to give a summary of what has become known thus far with reference to this very remarkable magnetic disturbance. Since the publication of that note, however, such a summary has already been made by Dr. H. Maurer and published in the “Annalen der Hydrographie und Maritimen Meteorologie,” 1904, Heft III, pp. 112–127 with references to the published accounts from various observatories. Dr. Maurer also gives a reproduction on two plates of the curves obtained at Potsdam, Bochum, Germany; and Uccle, Belgium. Also some of the MS. reports sent to the Journal have already appeared elsewhere. (See Dr. Maurer's references.)
The physical theory of the Earth's magnetic and electric phenomena: 1.
Authors: Bauer L. A.
Published: February 2008

a Foreword.

b The Ionic Theory of Magnetic Disturbances.
Glossary of atmospheric electricity terms
Authors: Strong W. W.
Published: February 2008

In this collection of terms used in connection with atmospheric electricity, especial attention is given to such which relate to ionization and radioactivity as it is in this direction that the greatest advances are being made.

In designating the various products of any radioactive family of elements, the order of the products will be that of their formation. In all other cases, the order will be an alphabetical one.
The magnetic character of the year 1909
Authors: van Dyk G.
Published: February 2008

The annual review of the “Caractère magnétique de chaque jour” for 1909 has been drawn up in the same manner as the preceding years. Forty‐two observatories contributed to the quarterly reviews, 38 sent complete data and 1 among them communicated its method of classification. Table II of the annual review, containing the mean character of each day and of each month and the list of “calm days” is reprinted here.
On certain new atmospheric‐electric instruments and methods
Authors: Swann W. F. G.
Published: February 2008

The following paper gives an account of new methods, or modifications of old methods devised by the author, for measuring the specific numbers and velocities of the atmospheric ions, the radioactive content of the atmosphere, and the atmospheric potential‐gradient.

THE NUMBER OF IONS PER C. C.
The lunar‐diurnal magnetic variation and its relation to the solar‐diurnal variation
Authors: Egedal J.
Published: February 2008

In an article published in this Journal the relation between the lunar‐diurnal and the solar‐diurnal variation has been discussed. The lunar‐diurnal variation being considered as generated by the solar‐diurnal variation under the influence of tidal forces, the following formula has been laid down: L/S f(ϕ) cos2ϕ = C (constant)

In this formula L is the amplitude of the 12‐hour term of the harmonic formula for the lunar‐diurnal variation, S the daily oscillation of the magnetic element considered, and ϕ the geographical latitude of the place.
Principal magnetic storms recorded at the Cheltenham Magnetic Observatory, April to December, 1927
Authors: Hartnell George
Published: February 2008

The most severe magnetic storm of the year was recorded at the Cheltenham Magnetic Observatory on October 12, 1927. It began abruptly at 5h 26m Eastern (75th meridian) standard time, and continued until 19h 15m. The extreme values occurred at the following times: West declination, maximum at 6h 34m, minimum at 8h 06m, range 2° 17′; horizontal intensity, maximum at 13h 43m, minimum at 6h 31m, range 519γ; vertical intensity, maximum at 6h 38m, minimum at 14h 26m, range 344γ. The most active portion of the storm corresponded with the period during which there was reported to be interference with telegraphic communication.
Effet de la distance de la lune sur l'amplitude diurne des éléments magnétiques
Authors: de Moidrey J.
Published: February 2008

Cet effet, fort petit assurément, que nous avons signalé en 1916 (Terrestrial Magnetism, 1916, p. 25), avait besoin d'être confirmé et étendu. Comme il est douteux que nous puissions désormais publier notre travail, on nous permettra de donner le résultat.

P et A désignent les amplitudes diurnes au périgée et à l'apogée, déterminées par 5 jours. Un contrôle par un seul jour donne même moyenne avec d'autres écarts moyens.
Provisional sunspot‐numbers for January to March, 1928
Authors: Wolfer A.
Published: February 2008

It is to be noted that these provisional sunspot‐n umbers are dependent alone on observations at the Zürich Observatory. The mean provisional number for the first quarter of the year 1927 was 80.2.
Some new theoretical and experimental results on the Aurora Polaris
Authors: Brüche Ernst
Published: February 2008

A recent paper in Zeitschrift für Astrophysik reported on the new theoretical investigations1 undertaken by Prof. C. Störmer and also on experimental research carried out by the author on the theory of the aurora polaris.2

The object of the theoretical investigation was to determine the periodic paths in space. The work dealt with types of paths which were hitherto unknown. The experimental research was confined to the practical production of electronic paths by employing models. The experimental results confirmed the theoretical work, and in addition, led to the determination of new paths.
The calculation of electrical resistivity for a region underlying two uniform layers
Authors: Roman Irwin
Published: February 2008

In a previous paper,3 formulas and tables were obtained for computing the apparent electrical resistivity of a bed underlying a single uniform layer. Since the present paper may be considered as an extension of the previous paper, we shall omit all references except those specifically needed.

There have been only a few papers on the present problem. Hummel4 has obtained a complete theoretical formulation for the simple case of a single overlying‐stratum. For the second approximation of two overlying‐strata, he has obtained formulas which can be interpreted most simply by anticipating the results of the present paper. The various potentials are expressible in double infinite series; for one counter, the general term is obtained; for the second counter, only the first four sets of terms are indicated; the law of formation for the general term is not given, except as just indicated; the results are given without derivation. The present results agree with those of Hummel, as far as his are given in explicit form. Stefanesco and Schlumberger5 solve the present problem in terms of Bessel functions and reduce their results to those of Hummel. Ehrenburg and Watson6 consider the problem of current‐flow through a medium composed of layers of equal thickness. The method is indicated for an arbitrary number of layers, but the explicit results are given only for those cases in which the upper layers are expressible without using more than five equally‐thick layers. The present results agree with those of these authors, as far as the two problems overlap, without extending their formulas. Both the Hummel and the Ehrenburg‐Watson papers seem to indicate a term‐by‐term calculation of the image‐strengths for positions accepted intuitively. There have been numerous other papers7 on the application of the electric resistivity‐method of prospecting, but few of them have any theoretical development, except on very broad approximations.
Auroral observations at the Alaska Agricultural College and School of Mines for the year 1931–1932
Authors: Fuller Veryl R.
Published: February 2008

In general the aurorae seen from College lie to the northeast. Arcs, especially the quiet homogeneous forms, are seen rising above the horizon at a point between 30° and 45° west of north, extending at various heights across the sky to the east. Homogeneous bands and usually bands with ray‐structure also take this direction. Fast‐moving forms with the exception of rays and coronas have their western foot somewhat farther west than the quiet forms and sometimes extend to the south‐eastern horizon. Although it is common for arcs and bands to extend across the sky through the zenith it is seldom, perhaps two or three times during a winter, that they lie low in the south. Diffuse surfaces, glows, and pulsating surfaces are more often seen in the northeast when they restrict themselves to any one section of the sky. These positions for the aurorae would be expected if one considers a map which shows the zones of equal frequency to pass over Alaska in a southeasterly direction. College lies just to the south of the zone of maximum frequency of display. This makes it a very satisfactory location for the observation of the aurorae.
The diurnal variation in magnetic and auroral activity at three high‐latitude stations
Authors: Davies Frank T.
Published: February 2008

The data used in this article were prepared for the purpose of comparing magnetic and auroral diurnal‐activity. Hourly magnetic character‐figures on a scale of 0, 1, and 2 are used to express magnetic character. As J. M. Stagg1 has found that such figures express satisfactorily the diurnal variation in irregular magnetic disturbance in high latitudes, the magnetic character‐graphs for the three high‐latitude stations considered in this article serve also to compare with the results of Stagg's investigation for ten other high‐latitude stations. The data used are for the following stations: The Byrd Antarctic Expedition Station at Little America, Antarctica, 1929–30; The United States Polar‐Year Station at Barrow, Alaska, 1932–33; and the Canadian Polar‐Year Station at Chesterfield, Northwest Territory, Canada, 1932–33.
Occurrences of rapid micropulsations at Sodankylä during 1932 to 1935
Authors: Sucksdorff E.
Published: February 2008

The rapid micropulsations, which are discussed herein, are shown in quick‐run records of terrestrial magnetism and earth‐currents as characteristic and easily distinguishable widenings of the curves, the shape of which is often reminiscent of that of a short shuttle. Single oscillations cannot be determined by the records, since the maximum period of an oscillation is less than 2 or 3 seconds—an interval not shown on the timescale of 180 mm per hour. Figure 1 gives reproductions of records, obtained February 6, 1935, of oscillations of this kind in magnetic declination and in both components of earth‐currents.

Even a casual glance at the records reveals that rapid micropulsations occur in groups, and only from time to time. Usually they take place in the course of a few consecutive days, after which sometimes a week, or even a month, may pass before new oscillations occur. It is seldom that such an oscillation occurs singly; usually there is a number of oscillations, interrupted by short intervals, for one hour, for several hours, sometimes even for more than 24 hours continuously, when the curve often resembles a pearl necklace consisting of oval pearls of different sizes.
On the theory of the unifilar variometer
Authors: Howe H. H.
Published: February 2008

Vectors are used in this treatment. Neglecting inhomogeneity of the field of control‐magnets, the simple, inclusive equation is obtained: Scale‐value per radian for changes normal to the magnetic axis = (k + P), where k is ratio of torsion‐constant to magnetic moment and P is field parallel to axis. Some consequences are discussed, showing superiority over other scale‐value equations. This equation is adequate for the scale‐value of and H‐variometer unless the readings are to be combined accurately with those of another variometer.

The subject is approached from a more general point of view. Horizontal intensity (H) is experimentally a function of ordinate (n), declination (D), and temperature (t). It is expressed by a Taylor's series in those variables. The resulting analysis shows: (a) This method avoids mistakes frequently made when second‐order effects are considered; (b) when properly defined in the most convenient way, the temperature‐coefficient is independent of ordinate and declination; (c) considerable error has resulted from the use of the wrong sign for the temperature‐coefficient of rigidity of quartz.

Consideration of variations of scale‐value shows: (a) Turning the torsion‐head affects the base‐line scale‐value very little; (b) a simple formula for the effect of change of optical lever with ordinate results; (c) the principal part of the variation with ordinate is due to the fact that when the magnet turns, part of the Earth's field acts parallel to its axis; (d) for a simple H‐variometer the temperature‐coefficients of base‐line value and base‐line scale‐value are precisely the same; (e) a sensitivity‐control magnet may cause a large temperature‐effect on scale‐value; (f) optical compensation produces an effect opposite in sign to the normal one, sometimes smaller, sometimes much larger; (g) the correction necessary to observed scale‐values is deduced. The effects of change of D are considered. These may be considerable even with a properly‐adjusted variometer, especially if it be uncompensated or have optical compensation.

A similar treatment for a D‐variometer shows: (a) The scale‐value may have considerable error unless corrected for the field of other magnets; (b) the effect of change of H is small and is wholly negligible if the variometer is properly adjusted—hence a D‐variometer is more accurate than any intensity‐variometer; (c) error in orientation may be detected and its magnitude may be estimated from the variometer's temperature‐coefficient.

Similar methods applied to the component in a fixed direction show that the formulas are somewhat simpler than for an H‐variometer. Maladjustments are discussed and it is shown that the formulas used for computing diurnal variations of X and Y from those of H and D are frequently incorrect. Certain possible improvements in instrument‐design and operation are suggested.
Abnormal ionization of the E‐region of the ionosphere
Authors: Berkner L. V. , Wells H. W.
Published: February 2008

Abnormal ionization of the E‐region of the ionosphere occurred very infrequently at Huancayo, Peru (12° south, 75° west), during nearly 8000 hours of observation. At Watheroo, Western Australia (30° south, 116° east), the effect was about 70 times as pronounced during the same period. Huancayo is on the geomagnetic equator, while Watheroo is in geomagnetic latitude about 42° south. This evidence suggests that sporadic ionization of the E‐region is a function of latitude, or more probably of magnetic latitude. It is observed that sporadic ionizations appear most frequently during local summer at stations in the temperate zones. Nevertheless, because of the much greater prevalence of thunderstorms near Huancayo as compared to Watheroo, the suggestion that the effect is related to thunderstorms does not seem to be supported. There is some evidence that the abnormal ionization may be related to magnetic bays and auroras which have a similar distribution with latitude and probably originate largely in the same atmospheric region.
On the variations of cosmic radiation during magnetic storms
Authors: Johnson Thomas H.
Published: February 2008

The experimental values of the geomagnetic cosmic‐ray effects have been used in calculating the change of cosmic‐ray intensity during a magnetic storm on the assumption that the magnetic disturbance can be regarded as a variation of the Earth's magnetic moment. The change in moment found necessary to produce the observed variations of cosmic‐ray intensity during the storm of April 1937 is of the order 150 times greater than any value simply reconcilable with the magnetic disturbances recorded.
Erdmagnetische Aktivität—V
Authors: Bartels Von J.
Published: February 2008

The tables of monthly and annual means for the measures u and u1 of terrestrial‐magnetic activity given in this Journal 1–4 for the years since 1835 are continued for the years 1935 and 1936 and supplemented by preliminary values, based on observations at Niemegk alone, up to March 1938. The recent sharp increase in magnetic activity is discussed and compared with the Zürich sunspot‐numbers R. The lag of u behind R is again noticeable. 1937 appears to be the most active year magnetically since the years around the high sunspot‐maximum 1870, although no individual storm of outstanding intensity occurred. Three successive storms gave the high value u = 2.74 to the month January 1938, a value comparable only with such well‐known months as November 1882, August 1917, March 1920, or May 1921. The different degree of terrestrial‐magnetic quietness reached during the last four sunspot‐minima is discussed. The minima of 1901 and 1913 were appreciably quieter than the minima of 1923 and 1933; this magnetic evidence agrees with solar observations in so far as the Sun was free of spots on more days around 1901 and 1913 than around 1923 and 1933.
Electrodynamic hydrology
Authors: Löwy H.
Published: February 2008

From the electric point of view the soil constitutes a mixture of dielectric and conductive substances. The substance of the rock and the air, contained in its pores, represent the dielectric part of the rock; the water and metallic ores the conductive part. In saturated rocks the water fills continuously the pores. This is the case in humid regions.
The electricity of continuous rain
Authors: Chalmers J. Alan , Little E. W. R.
Published: February 2008

The measurement of the electric charge on rain is of interest from two points of view; in the first place, the precipitation‐currents may be of importance in the discussion of what Wormell [see 23 of “References” at end of paper] has called “the electrical balance sheet of the Earth”; and further, the results for the charges on rain can give clues as to the mechanism involved in the acquisition of such charges and hence as to the processes at work in producing separation of charge in and below clouds.

Measurements in various parts of the world have shown that there is a positive excess of charge brought down to the Earth, more especially in rain classified as “continuous,” “ordinary,” or “non‐stormy” (German “Landregen”). Apart from this, little has been achieved in the establishment of general results capable of providing a basis for theoretical discussion.
Provisional Sunspot‐Numbers for August to October, 1941
Authors: Brunner W.
Published: February 2008

(Dependent alone on observation at Zürich Observatory)
American URSI Broadcasts of Cosmic Data, Giving American Magnetic Character‐Figure, CA, Three‐Hour‐Range Indices, K, and Mean K‐Indices, KA, For July to September, 1941
Authors: Johnston H. F.
Published: February 2008

Summaries of American URSI broadcasts have appeared regularly in this JOURNAL since the issue for December, 1930.

As set forth in this JOURNAL for June, 1937, “The Department of Terrestrial Magnetism and the United States Coast and Geodetic Survey with the cooperation of the United States Army and the United States Navy communication‐services and several amateur radio stations have undertaken to supply the American character‐figure based upon the, reports of the seven American‐operated observatories—those of the Department of Terrestrial Magnetism at Huancayo in Peru and at Watheroo in Western Australia, and those of the United States Coast and Geodetic Survey at Cheltenham (Maryland), Honolulu (Hawaii), San Juan (Puerto Rico), Sitka (Alaska), and Tucson (Arizona).” This character‐figure is being designated CA, and its values for the first twelve, the second twelve, and all twenty‐four hours of each Greenwich day for July to September, 1941, are given in Table 1.
Coronal radiation and ionospheric variations during the solar eclipse, July 9, 1945
Authors: Waldmeier M.
Published: February 2008

From the ionospheric observations made by O. Rydbeck and from the coronal observations made by the author it is deduced that the source of the solar ultra‐violet light, producing the E‐layer, lies in the innermost part of the corona in the regions of highest intensity of the 5303‐radiation. Very strong support to this conclusion is given by the fact that in these regions the temperature of the corona reaches its highest values.
Canopy and litter interception of rainfall by hardwoods of eastern United States
Authors: Helvey J. D. , Patric J. H.
Published: February 2008

All available reports of rainfall interception by hardwoods of the eastern United States were reviewed and, where possible, combined. Results from these independently designed and analyzed experiments showed that hardwood throughfall and stemflow vary over a surprisingly narrow range. Combined regression analysis describes the relation between inches of gross rainfall (P), throughfall (T), and stemflow (S) for summer as T = 0.901P ‐ 0.031, S = 0.041P ‐ 0.005; for winter as T = 0.914P − 0.015, S = 0.062P ‐ 0.005. These equations can be modified for specified forest conditions or for use with seasonal rainfall. Fifteen standard gages were found necessary to sample the growing season throughfall within 5% error limits, and 6 were necessary for the dormant season. Hardwood litter interception, studied inadequately in most parts of the east, amounted to 2 to 5% of the annual rainfall in the southern Appalachians. Applicability of equations to research and to practical problems is discussed as well as need for further research.
Inertial and storage effects in well‐aquifer systems: An analog investigation
Authors: Bredehoeft John D. , Cooper Hilton H. , Papadopulos Istavros S.
Published: February 2008

Equations for nonsteady groundwater flow are based upon Darcy's law, which is equivalent to assuming that the forces of inertia in the aquifer are negligible. Futhermore, derivation of these equations commonly assumes that the diameter of the pumped well is infinitesimal, which is equivalent to neglecting the additional storage in the well. The inertia of the column of water in the pumped and observation wells is also generally neglected in the derivation of these equations and in the analysis of drawdown measurements. However, for problems involving rapid acceleration of the water in the well and in the aquifer there is the possibility that the inertial forces and/or well storage may be significant. The effects of inertia in both the aquifer and the well, along with the effect of storage of water in the well, were investigated by electric analog. The results indicate that: (1) Some equations of groundwater flow are not applicable when the inertia of the water in the well and/or the storage of water within the well are taken into account; (2) A well can behave as an underdamped simple harmonic oscillator; i.e., it will oscillate following a sudden disturbance. The critical damping curves for 6‐inch‐diameter wells are presented. The ‘resonant’ frequency of the well‐aquifer system is to a large extent determined by the mass of ‘water’ in the well; (3) Except where changes in velocity occur very rapidly, as in forced oscillation, the effects of the inertia of water in the acquifer are negligible when compared with frictional (viscous) losses.
Runoff and hillslope erosion resulting from a high‐intensity thunderstorm near Mack, western Colorado
Authors: Hadley Richard F. , Lusby Gregg C.
Published: February 2008

Data on hydrologic and geomorphic processes from single storm events are rare. The opportunity to make such measurements occurred on August 12, 1964. The runoff and hillslope erosion resulting from a high‐intensity thunderstorm were measured in a small basin of 12 acres in western Colorado. The maximum intensity of rainfall for a 10‐minute period was 1.98 inches per hour. The total runoff as measured in a reservoir was 0.508 inch over the basin, and 0.90 inch of precipitation had been recorded when runoff stopped. Data from measurements of erosion pins along 6 hillslope profiles indicate that approximately 0.11 acre‐foot was eroded from the basin during the storm; survey of the reservoir shows that 0.090 acre‐foot was delivered to the lower end of the basin. Estimates of soil loss using measurements of erosion pin exposure are considered to be good in basins where sediment transport from hillslopes to the measuring point is not complicated by diverse topography or intermediate areas where deposition may occur.
Theoretical Analysis of Regional Ground Water Flow: 3. Quantitative Interpretations
Authors: Freeze R. Allan , Witherspoon P. A.
Published: February 2008

The natural basin yield of a ground water basin can be calculated from a quantitative analysis of the flow net obtained from a digital computer solution to a numerical mathematical model of the basin. The natural basin yield is an unique property of the basin and can be considered as a measure of the ground water recharge to the basin and a conservative estimate of the safe yield. Rates of ground water recharge and discharge vary from place to place throughout the areal extent of a basin; a quantitative analysis can be used to determine the positions of concentration. Quantitative interpretation of ground water flow nets can play an important role in the calculation of basin‐wide water balances due to the inter‐ relationships between ground water recharge and infiltration at one end of the flow system and ground water discharge, evapotranspiration, and stream baseflow at the other.
Dynamic Economic Efficiency of Water Quality Standards or Charges
Authors: Brown Gardner , Mar Brian
Published: February 2008

If a manager of a given water resource is uncertain of his power to set optimum stream standards or optimum effluent charges at every moment in time, there exist conditions, qualitatively identified, under which it may be dynamically more efficient for him to establish present water quality levels that will be optimum only at some future date than to try unsuccessfully to achieve optimum levels at every point in time. Excess demand functions and an aggregate nonlinear damage function are the conceptual underpinnings of this paper. (Key words: Water quality; dynamic efficiency; management)
An Accurate Small Orifice Rain Gage
Authors: Kalma J. D. , Lomas J. , Thaller M. , Shashoua Y.
Published: February 2008

An accurate, inexpensive, small‐orifice rain gage (modified Victor‐rain gage) with an orifice diameter of 29.2 mm was developed for use in rainfall networks and in agrometeorological and hydrological studies. It has a large capacity and can be installed and read easily. Comparison with standard rain gages showed good agreement under various conditions of exposure and with different observation techniques. Small amounts of rainfall are likely to be overestimated, owing to a film of water adhering to the glass water container of the gage, whereas hail tends to be underestimated. If the gage is intended for storage, the funnel tube has to reach nearly to the bottom of the inner vessel.
Sensitivity analysis method of system identification and its potential in hydrologic research
Authors: Vemuri Venkateswararao , Dracup John A. , Erdmann R. C. , Vemuri Narasimhamurty
Published: February 2008

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 demonstrated.
Random Walk and Random Roughness Models of Drainage Networks
Authors: Seginer Ido
Published: February 2008

A random walk model of a drainage network is generated on an underlying matrix by selecting at random the drainage direction out of the elementary areas. In a random roughness model, roughness heights of the elementary areas rather than drainage directions are assigned at random. The resulting topography of that model then uniquely determines the drainage pattern. An equivalence of the two models is suggested by the similarities, found in the mode of construction and by the equality of the probabilities of occurrence of some simple configurations. The random roughness model can yield values of primary probabilities, i.e., probabilities which can be used in the construction of a random walk model. The various types of drainage patterns are classified by the sets of primary probabilities which would generate them. Thus outcomes of homogeneous and isotropic matrices are classified as pure dendritic patterns. Outcomes of homogeneous matrices with probability sets derived from a sloping plane roughness model are classified as general dendritic (including parallel) patterns. Trellis, annular, and other patterns are considered as subgroups of the class of patterns generated on all other possible matrices.
Water temperature during the melting of lake ice
Authors: Williams G. P.
Published: February 2008

Water temperature and ice thickness were measured during the ice melt period at Bennett Bay, White Lake, Ontario. Water temperatures were as high as, 7.5°C under the melting ice cover. The heat needed to warm the water under the ice and to melt ice at the ice‐water interface was calculated for different periods and compared with the heat available from solar radiation that penetrated the ice cover. It was concluded from these calculations that solar radiation penetrating the ice caused the relatively high water temperatures observed under the melting ice.
Multireservoir Operation Studies
Authors: Roefs Theodore G. , Bodin Lawrence D.
Published: February 2008

An implicit stochastic process is compared to possible alternative analytical processes. An implicit stochastic process refers to a sequence of steps consisting of streamflow synthesis, deterministic optimization, and multivariate analysis of deterministic optimization results. The comparison is incomplete in that the performance of the multivariate analysis of results is not within the scope of this paper. Some formulations based on the method of Dantzig‐Wolfe decomposition are shown to be reasonably accurate representations of a nonlinear multireservoir deterministic optimization problem. One of these methods is shown to consume only moderate amounts of computer time for a problem of distinctly nontrivial size. The research issues yet to be resolved in achieving the overall objective (i.e., a multireservoir operation rule for flow regulation and energy production) are identified.
Finite Element Method of Analyzing Steady Seepage with a Free Surface
Authors: Neuman Shlomo P. , Witherspoon Paul A.
Published: February 2008

A new iterative approach to steady seepage of ground water with a free surface has been developed using the finite element method. This approach eliminates a number of difficulties that were inherent in the iterative procedures previously used to solve this problem and rapid convergence is now assured in all cases. The method is applicable to heterogeneous porous media with complex geometric boundaries and arbitrary degrees of anisotropy. It can handle problems where the free surface is discontinuous and where portions of the free surface are vertical or near vertical. In addition, infiltration or evapotranspiration at the free surface can be handled with ease. Several examples are included to demonstrate the power of this new approach and to show how it can apply to a wider variety of free surface problems than has been possible before.
Estimating Coefficients of a Flow Generator for Monotone Samples of Data
Authors: Crosby David S. , Maddock Thomas
Published: February 2008

If a set of flow records continuous in collection to the present has different starting times, it forms a monotone sample. The monotone sample may yield an inconsistent lag zero covariance matrix. In addition, it may be impossible to calculate real‐value coefficients for a flow generator, leading to some complex values for the synthetic flow trace. A technique is presented that produces a consistent lag zero covariance matrix and a real‐value multisite streamflow generator.
Empirical Relations in Properties of Unconsolidated Quartz Sands and Silts Pertaining to Water Flow
Authors: Wiebenga William A. , Ellis W. R. , Kevi L.
Published: February 2008

During a laboratory investigation using radiotracers, empirical formulas were developed to replace the ambiguous or incorrect Dupuit‐Forchheimer assumption used in relationships governing the flow of water through porous, unconsolidated materials ranging from clay to coarse sands or fine gravels. The Dupuit‐Forchheimer assumption states that the ratio of specific flow rate to average flow velocity is equal to porosity, but it is not specified whether true porosity or void ratio or specific yield, also called effective porosity, is meant. The hydraulic conductivity shows a good correlation with the maximum 10% grain size, and the ratio of specific flow rate to average flow velocity shows good correlation with functions of specific yield and percentile sorting coefficient. From field measurements of specific flow rate and average flow velocity the specific yield can be computed.
Possible Effects of Precipitation Modification on Stream Channel Geometry and Sediment Yield
Authors: Rango Albert
Published: February 2008

Stream channel geometry data were collected on 18 small watersheds in the West and sediment yield data were obtained for 673 small watersheds across the United States. Regression analysis was used to test what effects precipitation modification might have on these watershed parameters. No consistent changes of stream channel geometry between watershed areas were obtained, but the results indicated that the stream channel at a given location would adjust significantly in response to increases in precipitation (amounting to 14% annually). This response would probably initiate increased stream channel erosion. Sediment yield will increase substantially in semiarid regions with increasing precipitation until about 27 inches mean annual precipitation; at this point vegetation growth as a result of increased precipitation will begin to reduce sediment yield. Significant changes in stream channel geometry and sediment yield may result in sufficient economic damage to nullify many of the beneficial effects of weather modification.
Effect of Water Resource Investment on Economic Growth
Authors: Cox P. Thomas , Grover C. Wilford , Siskin Bernard
Published: February 2008

Counties in the northeastern United States in which large water resource development projects constructed between 1948 and 1958 were examined to determine whether the projects stimulated economic growth. A growth index was developed for use as a dependent variable, which was then tested for its relationship with several independent variables by regression and discriminant analyses. Selected nonproject counties were examined to check further the relationship between the independent variables and growth index. Counties with high growth indices and development projects were found to be near urban areas, whereas counties with low growth indices and no projects were in rural areas. A subsample of rural project and nonproject counties was examined; it showed no significant relationship to the growth index. From these findings we infer that water resource development projects are likely to be poor tools for accelerating economic growth of rural counties in the northeastern United States.
Soil Moisture Detection with Imaging Radars
Authors: Macdonald Harold C. , Waite William P.
Published: February 2008

The high degree of correlation between the electrical properties of soil and soil moisture content are well known. Considerable experimental work has been conducted by using radar for the determination of soil moisture. However, in the transition from a controlled measurement device to an operational imaging radar, the effects of soil moisture have been extremely difficult to separate from other terrain parameters influencing the radar return signal.

The data presented in this study suggest that presently available dual polarized, K‐band, side‐looking imaging radars provide a capability for revealing a qualitative estimate of soil moisture content. When used as a supplement to aerial photography in temperate climates, radar imagery analysis will decrease the ambiguity of soil type reconnaissance. In the Arctic, an imaging radar may provide data for mapping regions of permafrost, and this process could be accomplished in a sequential manner regardless of weather or time of day. The use of additional multifrequency multipolarization imaging radars and the relative foliage penetration of each should be investigated as a possible means of gathering quantitative soil moisture information.
Operating Rules for Joint Operation of Raw Water Sources
Authors: Joeres Erhard F. , Liebman Jon C. , Revelle Charles S.
Published: February 2008

The techniques of linear programing, synthetic streamflow generation, and simulation are merged to derive operating rules for a multiple source water supply. The approach is general; it is here applied to the Baltimore water supply, where upland reservoirs furnish water by gravity flow, and a backup supply delivers pumped water from the Susquehanna River. The reservoir water is essentially free but subject to random storage fluctuations, whereas the backup supply has constant availability but a high operating cost. The algorithm assumes reservoir release to be a linear function of available storage at the beginning of a period. Chance constrained linear programing is employed to select candidate operating policies which are subsequently tested by a simulation program for long‐term performance. Results indicate that substantial savings can be effected with concurrent frequent improvement in system performance, when compared with operation under a constant reservoir draft policy.
Predicting the Date of Lake Ice Breakup
Authors: Williams G. P.
Published: February 2008

Standard deviations for lake breakup dates were calculated for all lakes in Canada with reasonably long breakup records and for five lakes in Wisconsin with long‐term records. Standard deviations were about 13 days for coastal lakes and 7–11 days for continental lakes. The accuracy of the melting degree day method of predicting breakup dates were investigated for 12 of these lakes; standard deviations ranged from 3.3–8.0 days. Regression equations for predicting breakup dates were developed from past breakup and air temperature records for the 12 lakes; standard errors ranged from 1.6–4.3 days. General forecast guidelines were developed for application to lakes with limited breakup records. The equations and forecast guidelines are suitable only for continental lakes where wind and river inflow effects are not dominant.
Application of Statistical Decision Theory to Water Use Analysis in Sevier County, Utah
Authors: Andersen Jay C. , Hiskey Harold H. , Lackawathana Suwaphot
Published: February 2008

Statistical or Bayesian decision theory was applied to a farm management situation in Sevier County, Utah, which is characterized by risk and uncertainty with respect to the supply of late season water. Information on reservoir carry‐over and mountain snowpack becomes available just before resources must be committed. These data are incorporated into the model as predictors of the late season water supply. Use of this predictive information is compared to the ‘no data’ situation, in which the predictive information is not used, and also to the ‘perfect knowledge’ situation, in which the availability of full information at the time of resource commitment is assumed. A limited growing season and other physical constraints along with lack of markets restrict the flexibility of the management decisions so that the profitability of adapting the technique is not great in the present application. However, the technique is shown to be usable and potentially profitable in a variety of management situations.
A Fast Fractional Gaussian Noise Generator
Authors: Mandelbrot Benoit B.
Published: February 2008

By design fast fractional Gaussian noises (ffGn) have the following characteristics: The number of operations needed to generate them is relatively small. The long run statistical dependence that they exhibit is strong and has the form required for self similar hydrology. Their short run properties, as expressed by the correlations between successive or nearly successive yearly averages, are adjustable (within bounds) and can be fitted to the corresponding short run properties of records. Extension to the multidimensional (multisite) case should raise no essential difficulty. Finally, their definition, as sums of Markov‐Gauss and other simple processes, fits the intuitive ideas that climate can be visualized as either unpredictably inhomogeneous or ruled by a hierarchy of variable regimes.
Estimated Groundwater Yield following Strip Cutting in Pine Plantations
Authors: Urie Dean H.
Published: February 2008

Groundwater recharge balances were determined under 40‐acre blocks of a jack pine (Pinus banksiana Lamb) plantation in northwestern lower Michigan during the 4 years following the removal of 50% of the trees in clear‐cut strips. Analyses were made by graphical interpretation of diurnal fluctuations and by use of finite difference equations. In the numerical method, weekly water table elevation measurements over each 40‐acre block were used to determine water table convexity, which was then linearly related to the groundwater inflow‐outflow balance.

Results from both methods of analysis showed the effect of strip cutting as increased ground‐water yields. Estimates of water yield by the two methods differed primarily as a result of poor estimates of net evaporative loss from the saturated zone using the graphical method.

Three other tests of cutting effects on groundwater recharge supported the budget estimates of treatment effect. Approximately 3 inches per year of additional water was produced as a result of the strip cut during the first 4 years after cutting. The numerical analysis showed that the amount of treatment effect decreased rapidly over this period.
A Functional Iteration Technique for Solving the Richards Equation Applied to Two‐Dimensional Infiltration Problems
Authors: Brutsaert Willem F.
Published: February 2008

In the solution of nonlinear parabolic partial differential equations, such as the Richards equation, classical implicit schemes often oscillate and fail to converge. A fully implicit scheme has been developed along with a functional iteration method for solving the system of nonlinear difference equations. Newton's iteration technique is mathematically the most preferable of all functional iteration methods because of its quadratic convergence. The Richards equation, Newton‐linearized with respect to relative permeability and saturation as functions of capillary pressure, is particularly aided by this new approach for problems in which saturations vary rapidly with time (infiltration fronts, cone of depression near a well bore, and so forth). Although the computing time is almost twice as long for a time step with Newton's iteration scheme, the smaller time truncation than that of classical implicit schemes and the stability in cases in which classical schemes are unstable permit the use of much larger time steps. To demonstrate the method, heterogeneous (layered) soil systems are used to simulate sharp infiltration fronts caused by ponding at the soil surface.
On determination of BOD and parameters in polluted stream models from DO measurements only
Authors: Koivo A. J. , Phillips G. R.
Published: February 2008

The biochemical oxygen demand (BOD) concentration, the BOD removal coefficient, and the average daily photosynthesis minus respiration term of a polluted stream model can be determined by using only measurements of the dissolved oxygen (DO) concentration taken at discrete locations and the values of the remaining parameters. The mathematical model used is a modified Streeter‐Phelps relationship describing the average daily DO and BOD concentrations for a polluted stream under steady state conditions. The procedure provides a least squares fit to the DO measurements and is illustrated by pertinent numerical examples.
Decomposition and multilevel techniques for water quality control
Authors: Haimes Yacov Y.
Published: February 2008

The advantages of a system of effluent charges to control water quality and abate pollution are discussed. A decomposition and multilevel optimization approach that is capable of handling large‐scale and complex nonlinear systems is reported to be successfully applied to problems of water quality control. A simple example is introduced to demonstrate the methodology of the multilevel approach. A summary of computational experience in comparing the multilevel approach with the Dantzig‐Wolfe and quadratic programing methods as applied to the Miami River data is given.