bluuebunny/crossref_metadata_2025 huggingface dataset:
Recent Geomagnetic Work and Plans of the Dirección de Meteorología, Geofísica, e Hidrología, Ministerio de Agricultura, Republica Argentina
Authors: Galmarini Alfredo G.
Published: February 2008

An isogonic map of Argentina was recently published by the Dirección de Meteorología, Geofísica, e Hidrología of the Ministry of Agriculture giving results of the magnetic survey for epoch January 1, 1944. Recent field‐work included complete observations at 178 points. We shall soon publish isodynamic maps of horizontal and vertical force arid an isoclinic map. We intend now to maintain two parties in the field continuously, which will effect geomagnetic determinations in an increasing number and make possible publication of our magnetic maps at rather regular intervals based upon more widely distributed data.
Cheltenham Magnetic Observatory, January to March, 1944
Authors: Hershberger John
Published: February 2008

(Latitude 38° 44′.0 N., longitude 76° 50′.5 or 5h 07m.4 W. of Gr.)

January 10—A bay in H in the last three‐hour period of January 10, GMT, gave a K‐index of 6, and was followed by minor activity for a week or more.
Huancayo Magnetic Observatory, January to March, 1944
Authors: Ledig Paul G.
Published: February 2008

(Latitude 12° 02′.7 S., longitude 75° 20′.4 or 5h 01m.4 W. of Gr.)

February 7—A short magnetic disturbance was recorded beginning at 12h GMT, February 7. It was ushered in by a decrease of about 150 gammas in H during the first hour and followed by a number of sharp peaks and bays till after 18h, and then continued for about two hours more in a mild form. D and Z were also noticeably disturbed during the period of activity in H. H was somewhat below normal for the next day. The total range in H was 180 gammas during the disturbed period.
Solar and Magnetic Data, January to March, 1944, Mount Wilson Observatory
Authors: Nicholson Seth B. , Mulders Elizabeth Sternberg
Published: February 2008

The magnetic storm of January 10 to 18, 1944, occurred during a quiescent period on the Sun. No sunspots were observed from January 3 to 18. A very small spot (Mount Wilson No. 7633), seen on that day only, was in the bright calcium flocculi over the region where No. 7631 (which was accompanied by a magnetic storm from December 16 to 21, 1943), had been on the previous rotation of the Sun [see Terr. Mag., 49, 63 (1944)]. This region had returned to view at the east limb on January 9.
Watheroo Magnetic Observatory, October to December, 1944
Authors: Parkinson W. C.
Published: February 2008

(Latitude 30° 19′.1 S., longitude 115° 52′.6 or 7h 43m.5 E. of Gr.)

December 15–18—A disturbance of moderately severe intensity began with a “sudden commencement” in all three elements at 18h 52m GMT, December 15. Small rapid fluctuations began at 23h 35m on the same day and continued intermittently until 10h 20m December 16, these fluctuations being particularly active between 06h 50m and 08h 00m, December 16. At 13h 30m, December 16, large sweeping movements began in all three elements, H decreasing to a minimum value at 15h 57m and the Z‐trace going beyond the limits of registration between 13h 52m and 15h 38m. After 20h 30m, December 16, the traces steadied somewhat although still slightly disturbed, with H still considerably below its normal value. At 08h 54m, December 17, the traces again became more disturbed with fairly large sweeping movements taking place in all three elements, and with H increasing in mean value. At 23h 00m, December 17, these leisurely movements gave place to small fluctuations which persisted until 08h 30m, December 18, after which the traces resumed their normal character. A faint aurora was observed between 15h and 18h, December 16. Ranges: D, 32′.2; H, 263 gammas; Z, greater than 197 gammas.
On the relation between geomagnetism and the circulatory motions of the air in the atmosphere
Authors: Wulf Oliver Reynolds
Published: February 2008

General considerations

The dynamo‐theory of the diurnal variation of the Earth's magnetic field offers an explanation of this phenomenon that is expressed in terms of diurnal motions of the air in the high atmosphere. These motions must be related, even if very indirectly, to the air‐flow below through the changes of horizontal pressure‐distribution, shear, and the vertical movements of the air that in some degree must accompany all of these motions. The altitudes in which occur the air‐motions that generate the electromotive forces and the atmospheric‐electric currents of the dynamo‐theory are not surely known, but that they lie far above those accessible to sounding‐balloons seems certain. Perhaps the best estimate of the altitudes at which these atmospheric‐electric currents flow may be had from the requirement that, at these altitudes there be sufficient molecular collisions and at the same time sufficient ionization that the direct‐current conductivity of the air be relatively large. As an approximate estimate of this it seems that an altitude at the base of or somewhat below theE‐layer of the ionosphere may be taken, which, as an abbreviation to aid in discussion, will be spoken of in the present work as the 60‐ to 80‐km region. How far below this a relation can still be perceived between the air‐motions occurring there and those below remains to be discovered.
Diffusion of ions in the ionosphere
Authors: Ferraro V. C. A.
Published: February 2008

(1) Introduction—The variation of ionic density in the ionosphere with height at any time of the day has been the subject of a number of theoretical studies by E. O. Hulburt and S. Chapman, amongst others. Chapman's discussion is based on the supposition that the disappearance of electrons in the ionosphere is due entirely to electron‐positive ion recombinations, and Appleton and Naismith [see 1 of “References” at end of paper] find that this simple theory agrees well with the observed variation of the maximum electron‐density in the E‐ and F1‐layers. His theory, however, does not take into account the possible influence of the downward diffusion of ions and an approximately equal number of electrons. Hulburt [2], summing up the results of his investigation, remarks that as regards the variation of ionic density “there is an uncertainty in the case of F2 and F1 which may or may not turn out to be important.
American magnetic character‐figure, CA, three‐hour‐range indices, K, and mean K‐indices, KA, for April to June, 1945
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 April to June, 1945, are given in Table 1.
Summary of the year's work, to June 30, 1945, Department of Terrestrial Magnetism, Carnegie Institution of Washington
Authors: Fleming J. A.
Published: February 2008

The long‐sustained effort required for waging a war of world‐wide extent continued unabated, during the year July 1, 1944, to June 30, 1945, and rendered impossible the execution of anything like the normal program of the Department of Terrestrial Magnetism. Military and naval operations, so inimical to geophysical investigations requiring international cooperation, of which terrestrial magnetism and electricity are good examples, have greatly interfered with work in this field of research. It has not been possible to equip expeditions for field‐work in foreign lands and on the oceans for providing the much needed data for secular‐variation studies. Although practically all of the Department's staff have turned attention to the solution of problems connected with the war, considerable progress along certain lines has been made.
An addition to the table of secular variations of the solar cycle
Authors: Gleissberg W.
Published: February 2008

Yesterday I received, from Zürich, No. 144 of the Astronomische Mitteilungen containing the determination of the last sunspot‐minimum. This determination yields 1944.2 for the epoch of the minimum and 7.7 for the smallest relative sunspot‐number. From these data, epoch and depth of the secularly smoothed minimum of 1923 can be calculated; thus a new line can be added to my table of secular variations of the solar cycle [Terr. Mag., 49, 243–244 (1944)]. This new line reads as follows:MinimaEpoch Weight (m − m) r1923.5 46 10.8 3.9
Tucson Magnetic Observatory October to December, 1945
Authors: Westerman C. Edward
Published: February 2008

(Latitude 32° 14′.8 N., longitude 110° 50′.1 or 7h 23m.3 W. of Gr.)

December 13–14—A sudden increase in H of 10 gammas in less than a minute, commencing at 12h 39m GMT, December 13, marked the beginning of a moderate storm. During the first seven hours of the storm the activity was of fairly short period and small amplitude in both D and H. At 16h the H started decreasing at an irregular rate and, after reaching a minimum at 05h, December 14, began to increase and at 15h, December 14, although H was still approximately 100 gammas below normal, the disturbance apparently ended. The increase in declination from 20h, December 13, until 09h, December 14 was followed by a bay lasting an hour, during which D had a range of 21′. Z was relatively undisturbed during the storm. Ranges: D, 21′; H, 203 gammas.
American magnetic character‐figure, CA, three‐hour‐range indices, K, and mean K‐indices, KA, for January to March, 1946
Authors: Scott W. E.
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 January to March 1946, are given in Table 1.
Eclipse‐effects in F2‐layer of the ionosphere
Authors: Wells H. W. , Shapley A. H.
Published: February 2008

Analyses of ionospheric observations of the partial eclipses of February 4–5, 1943, August 1, 1943, and January 25, 1944, made at ionospheric observatories of the Department of Terrestrial Magnetism of the Carnegie Institution of Washington (DTM CIW) show that the ionization of the F2‐layer was subnormal before the beginning of the eclipse in each case, and remained low longer than expected after the eclipse. Examination of this effect with relation to concurrent activity on the Sun, especially bright regions of the corona, indicates that radiation from beyond the limb of the Sun may contribute to the ionization of the region. Values of the recombination‐coefficient for the F2‐layer estimated from these eclipse observations lie between 10−9 and 2 × 10−10. The larger values obtained when the apparent heights, as well as the ion‐densities, were lower. At Huancayo, during the January 25, 1944, eclipse, the F2‐layer rose bodily to great heights with a velocity of the order of 200 km per hour, and a new F‐region stratification developed at normal height.
Alibag Magnetic Observatory April to June, 1946
Authors: Rao M. P.
Published: February 2008

(Latitude 18° 38′.3 N., longiude 72° 52′.3 E. or 4h 51m.5 E. of Gr.)

April 14–15—A disturbance with a very gradual commencement near 08h 30m GMT, April 14, continued till about 20h, April 15, resulting in two K‐indices of 5.
International Council of Scientific Unions
Authors: Stratton F. J. M.
Published: February 2008

The first General Assembly of this Council since the war has just concluded its meetings, which were held at the rooms of the Royal Society, London, under the Presidency of Dr. H. R. Kruyt of Utrecht University. Over seventy representatives of the principal Scientific Academies, of a number of National Research Councils, and of the various International Scientific Unions were present. The countries officially represented were Australia, Belgium, Canada, China, Czechoslovakia, Denmark, Egypt, France, Great Britain, India, Italy, Netherlands, Netherlands East Indies, New Zealand, Norway, Peru, South Africa, Sweden, Switzerland, United States, and Yugoslavia. In addition as guests a welcome was extended to Monsieur A. Establier and Madame Malterre of the International Organisation of Intellectual Cooperation of the League of Nations and Dr. Needham head of the Scientific Division of the Preparatory Commission of the United ‐Nations Educational, Scientific, and Cultural Organisation (UNESCO).
Watheroo Magnetic Observatory May to September, 1946
Authors: Wood F. W.
Published: February 2008

(Latitude 30° 19′.1 S., longitude 115° 52′.6 or 7h 43m5 E. of Gr.)

The following four additional storms were recorded during May and June, 1946; descriptions were received after publication of the June issue of the Journal.
Dual laws of the course of magnetic disturbances and the nature of mean regular variations
Authors: Nikolsky A. P.
Published: February 2008

The investigation of magnetic storms by the data of the observatories located in high latitudes has revealed at a number of stations the presence of two maxima in the diurnal variation of magnetic disturbance. The study of a vast material, in particular the magnetic observations at Tikhaya Bay for nine years, has shown the changes of magnetic disturbance in the morning and the night hours to depend on different laws. This, in its turn, gave reasons to suggest that the magnetic disturbances in the morning and the night are of different nature. The above conclusion has proved to be of great importance for the further investigation of the diurnal variations of the disturbed magnetic field in high latitudes.

Moreover, one has scrutinized in detail the connection between the intensity of accidental irregular fluctuations of the magnetic field (Di), during magnetic storms and the corresponding absolute values of the horizontal component. According to the data at Tikhaya Bay, the correlation‐coefficient between these phenomena was found to be high, r = − 0.70 ± 0.04.

The further investigation of the disturbed magnetic field in the same direction, from data at Tikhaya Bay, has shown that the absolute values of the horizontal component for individual quiet hours, selected from the disturbed days, are exactly the same as those on the quietest days. The reduction of the magnetic data for Dickson and Wellen has confirmed the results obtained above. This result cannot be explained from the point of view of our notions on the nature of the phenomena of Sd and Dst in the field of magnetic storms.

The result of the present investigation permits the suggestion that during magnetic storms there are only accidental discrete and short‐period disturbed magnetic fields caused directly by the corpuscular streams coming from the Sun. The mean, regular variations Sd and Dst in the disturbed magnetic field do not correspond to any real, prolonged phenomena in the field of magnetic storms and are fictitious, that is, merely statistical results.
Electric current as a probably cause of daily magnetic variation
Authors: Terada K.
Published: February 2008

Summary—This paper was read, as early as 1941, at the meeting of the Physico‐Mathematical Society of Japan held at Hiroshima University. The Japanese text of this paper (with English abstract) with some of the details was published in the Journal of Meteorological Society [Ser. II, 20, 353–369 (1942) and 21, 171–178 (1943)]. The complete paper has not yet been published because of the War.

The paper is restricted to some physical points only and detailed mathematical treatments and the numerical data are omitted.
Revised form of solar and magnetic data from Mount Wilson Observatory
Authors: Nicholson Seth B.
Published: February 2008

Mrs. Mulders, who for many years has been estimating the solar character‐figures from K2 and Hα spectroheliograms, is leaving the Observatory this month. She is moving to San Francisco where her husband has accepted a position with the United States Navy.

It seems to me that this is a good time to terminate the publication [in Terr. Mag. since 1930] of these character‐figures, which have not proved very useful and whose publication at Zurich was terminated some years ago. Since several magnetic observatories estimate the magnetic character‐figure and since other more quantitative measures are superseding it, I question the advisability of continuing its publication also. It is probably worth while to continue the table of magnetic storms and the remarks about the solar activity contemporary with them.
Hermanus Magnetic Observatory January to March, 1947
Authors: van Wijk A. M.
Published: February 2008

(Latitude 34° 25′.2 S., longitude 19° 13′.5 or 1h 16m.9 E. of Gr.)

January 4–6—A storm of moderate intensity began with a sudden commencement at 11h 17m GMT, January 4 (H, 39 gammas in seven minutes), and continued until about 16h, January 6. Five K‐indices of 5 were recorded during that period.
The ionosphere as a measure of solar activity
Authors: Phillips M. Lindeman
Published: February 2008

Critical frequencies of all regular ionospheric layers vary diurnally, seasonally, with geographic latitude and longitude, and with solar activity so that, for any location and any season

urn:x-wiley:00968013:media:tma33214:tma33214-math-0001

where f0 is the critical frequency, G and H are functions of (t), the time of day, and S is the sunspot‐number. For locations where such ionospheric trends are well established, observations of critical frequency may be used to determine an ionospheric “sunspot‐number”. If values of F2‐layer critical frequency for hours near local noon are used, since these generally have the most pronounced variation with solar activity, the ionospheric “sunspot‐number” obtained is considerably closer to its running‐average value than are ordinary sunspot‐numbers to their running averages. In addition, this measure is practically independent of varying atmospheric conditions and personal variation among observers, and therefore probably presents a more precise index of solar activity.
Discussion of data for magnetic declination at Oslo, 1843–1930, and before 1843
Authors: Wasserfall K. F.
Published: February 2008

The Magnetic Observatory at Oslo (latitude 59° 54′.7 north, longitude 10° 43′.4 east) was founded by Professor Christopher Hansteen. The author has compiled the resulting data as regards horizontal intensity and magnetic activity in this Journal [see 1, 3, 5 of “References” at end of paper]. The daily values at 09h and 14h of magnetic declination are given in reference [2] for 1843–1930; the present communication summarizes the general discussion of the material for declination with some remarks on correlation with sunspot‐activity and observations made prior to the series begun by Hansteen in 1842.

There were naturally many difficulties encountered in compiling reduction constants because of changes in azimuth of mark, alterations and repairs of buildings, changes of scale‐values and of base‐lines, and magnetic station‐differences for the several piers used in so long a period. Figure 1 gives a plan of the Observatory and environs as at present; originally the area was a rural one but it is now surrounded by a modern city. The hut for observations of declination, which was removed in 1908, was at point marked U.L. (now the University Library). The plan shows also the situation of the four piers I–IV, the pier where the unifilar magnetometer was mounted, and the one where the bifilar magnetometer was installed. It is of interest to note the isogonic lines at the Oslo Observatory Park and in the general region surrounding Oslo, as shown by Figures 2 and 2A for the epoch 1929.5.
On minute, rapid, periodic changes of the Earth's magnetism
Authors: Eschenhagen Max
Published: February 2008

In a previous communication to the Academy, a curve was exhibited which had been obtained at the Potsdam Magnetic Observatory by automatic photographic registration of the horizontal component of the earth's magnetic force. The striking feature of this curve was the fact that, in addition to the usual larger perturbations, there was a series of very small waves having nearly the same constant period, so that these waves could, in a certain way, be regarded as constituting the elementary pulsations of the earth's magnetism.

Since then it has been possible to obtain about sixty such curves. The sensitiveness of the intensity variometer was, as before, a very high one (1 mm. of ordinate=0.00004 cm−½ g½ sec−1), and for the time‐scale a length of abscissa of 24 cm. was taken to represent one hour, hence about twelve to sixteen times that of the usual registration.
International Magnetic Conference.—Welcoming Address
Authors: Ayrton W. E.
Published: February 2008

Section A this year is very fortunate in having its meetings associated with those of an “International Conference on Terrestrial Magnetism and Atmospheric Electricity,” which is attended by the members of the “Permanent Committee for Terrestrial Magnetism and Atmospheric Electricity” of the “International Meteorological Conference.” It has been arranged that this Permanent Committee, of which Professor Rücker is the president, shall form part of the General Committee of Section A, and shall also act as the Committee of the International Conference, which will itself constitute a separate department of Section A. For the purpose, however, of preparing a Report to the International Meteorological Conference, and for similar business, this Permanent Committee will act independently of the British Association.

My first duty to‐day, therefore, consists in expressing the honor and the very great pleasure which I feel in bidding you, members of the International Conference, most heartily welcome.
On the establishment of temporary magnetic observatoriés in certain localities, especially in tropical countries
Authors: von Bezold  , Rykatschew
Published: February 2008

Die nachstehenden Vorschläge stützen sich wesentlich auf eine Abhandlung, welche der eine der Unterzeichneten im Jahre 1897 veröffentlicht hat. In dieser Arbeit wurde versucht, durch Vergleichung mit den Beobachtungen die Hypothese zu prüfen, dass die Kräfte, welche die erdmagnetischen Erscheinungen hervorrufen, in der Erdoberfläche selbst ein Potential besitzen; auf Grund von Werthen, die ihm Herr A. Schmidt für je 72 um je 5 Längengrade von einander abstehende Punkte auf 4 Parallelkreisen mitgetheilt hatte, gelang der Verfasser zum Schluss, dass die in Procenten der Amplitude des Potentials ausgedrückten Abweichungen von jener Hypothese um den 40—45 Grad nördlicher Breite am grössten ausfallen, d. h. also gerade in jenen Breiten, für welche die meisten und besten Beobachtungen vorliegen ; diese Abweichungen erreichen hier Werth bis zu 8% der Amplitude, während sie in niedrigen Breiten nur wenige Beobachtungen vorhanden sind, viel kleiner sind, theilweise sogar ganz verschwinden. Für die Theorie des Erdmagnetismus wäre es von höchster Wichtigkeit, darüber Gewissheit zu erlangen, ob dieses Resultat nicht vielleicht durch den Mangel an Beobachtungen, besonders aus dem Aequatorialgebiete, bedingt ist.

In derselben Arbeit hat der Autor auf Grund der von A. Schuster mitgetheilten Werthe eine Karte entworfen, welche für den Sommer ein anschauliches Bild vom Verlaufe der Gleichgewichtslinien des Potentials der täglichen Variation giebt; die Darstellung der Karte bezieht sich auf den Mittag nach Greenwicher Zeit.
On the interpretation of earth current observations
Authors: Schuster Arthur
Published: February 2008

If two metallic plates are inserted into the ground and connected by a wire, an electric current is found to traverse the conductor, and this is generally called the “earth current.” It is not, however, obvious at first sight what the connection is between this observed current and that which traverses the ground when the earth plates are removed. The statement sometimes made that the observation gives the difference of potential of the earth at the two points at which, the plates are inserted, would be true, provided the connecting wire has a sufficiently large resistance, if earth currents were only due to chemical or thermo‐electric forces. But as there can be little doubt that earth currents are chiefly, if not entirely, effects of induction, a separate investigation is necessary as to the interpretation to be attached to the galvanometer indications.
Errors involved in using zinc chloride solution in floating lysimeters
Authors: King K. M. , Mukammal E. I. , Turner V.
Published: February 2008

A differential transformer recording system, measuring changes in the level of the zinc chloride solution used to float sensitive lysimeters measuring evapotranspiration and dew, recorded errors arising from temperature changes in the solution. Since zinc chloride has certain advantages for use in floating the lysimeters, various methods were devised for compensating for these errors. Although complete correction was not obtained, the temperature errors were reduced to insignificant values with the use of a double float in a stilling well radially divided.
The physical chemistry and structure of sea water
Authors: Horne R. A.
Published: February 2008

Temperature and hydrostatic pressure disrupt the structure of sea water; both the bulk order and the local order in the hydration atmospheres of ions are affected. These structural changes in turn affect transport processes such as electrical conductivity and viscous flow.
Politics and organization in water resource administration: A comparative study of decisions
Authors: Munger Frank , Houghton Anne
Published: February 2008

Organizational arrangements for the exercise of controls over surface water flows have taken a wide variety of forms. Political considerations have largely determined the choices between alternatives of private versus public development, state or local versus federal development, and the selection among alternative federal development agencies. Because of variations in the effectiveness of political forces through time and space, the development pattern in almost every major river valley is distinctive to itself. An analysis of control arrangements in a sample of 145 reservoirs indicates that public enterprise has almost entirely replaced private in current developments but that both state and federal water agencies show continuing vitality. The distinctions among levels of governmental control are closely related to the functions performed, with local governments most active in the provision of water supplies; special districts in reimbursable functions; state agencies in nonreimbursable functions; and the federal government in projects including flood‐control (and navigation) benefits.
Water quality improvement programming problems
Authors: Sobel Matthew J.
Published: February 2008

Recent years have seen a marked increase in the rate of investment in facilities for water quality control and a concurrent recognition of the need to program water resource use on a regional basis. This paper outlines the nature of regional water quality systems and presents programming models for several water quality improvement problems. A linear programming formulation of a static improvement in quality is contrasted with a traditional policy for programming improvements; the traditional policy results in a mixed integer problem. The maximization of the ratio of benefits to costs of an improvement program is transformed to a linear programming problem. A stochastic natural environment leads to other programming models. A discussion of the application of least‐cost models terminates the paper.
Synthesis of hourly rainfall data
Authors: Pattison Allan
Published: February 2008

A study was made of the possibility of representing the hourly rainfall process observed at a point by a simple model using a digital computer. The purpose of the modeling procedure is to produce synthetic hourly rainfall data for the Stanford watershed model to make possible long records of synthetic streamflows. The model represents the hourly rainfall process by a sixth‐order Markov chain and is shown to be a suitable procedure. Dry periods between storms are found to be longer than dry periods that occur in nature. When used in the Stanford watershed model, the synthetic data produce hydrologic characteristics for a test watershed that are in good agreement with those derived from historic data.
Some operating characteristics of a rapid response tensiometer system
Authors: Watson K. K.
Published: February 2008

An experimental arrangement for measuring soil‐water suctions with rapid response is described and the operating characteristics of the tensiometer‐transducer system discussed. The equations relating to the response of the equipment are given, and a dynamic correction procedure using an iterative approach is illustrated.
Energy, total carbon, and oxygen demand
Authors: Busch A. W.
Published: February 2008

The biodegradable content of organics in aqueous solution can be assessed in two ways: by measuring the change in organic content effected by bacterial metabolism; or by measuring the consumption of oxygen by bacteria in effecting the removal of organics. In addition to oxygen, two possible parameters for pollution measurement are thermodynamic energy change and total carbon change. The validity of applying thermodynamic concepts to biological systems is questioned. Total carbon changes during the process of biological oxidation are considered to offer an excellent potential as a measure of biodegradable organic content. The use of carbon as a parameter in the context of the two analytical procedures derived at Rice University affords a flexibility in selection of technique based on the required precision of results. (Key words: Pollution measurement; oxygen demand; bacterial synthesis.)
Response of springflow to some climatic variables in southwestern Wisconsin
Authors: Curtis Willie R.
Published: February 2008

Field investigations show the relationships of springflow to some climatic variables in southwestern Wisconsin. These observations indicate that springflow fluctuates in much the same manner as recharge to groundwater. In addition, short‐period fluctuations in springflow are caused by changes in barometric pressure. This influence is more pronounced during the dormant season. A good correlation was found between springflow and the base flow of a nearby stream. (Key words: Base flow; springs.)
Evaluation of an evapotranspirometer for peat bogs
Authors: Bay Roger R.
Published: February 2008

A bottomless evapotranspirometer, 10 feet in diameter, was developed for use in saturated organic soils and was tested under open bog conditions. Weekly water losses from two evapotranspirometers compared favorably with pan evaporation and with potential evapotranspiration calculated by climatological methods. Provided that they are constructed to reach slowly permeable peat types to minimize bottom seepage, these installations appear to be useful for measuring evapotranspiration to test the applicability of formulas based on climatological data or to measure on site the effects of water management. (Key words: Bogs; climate; evapotranspiration; instruments)
Potential evaporation: The combination concept and its experimental verification
Authors: Van Bavel C. H. M.
Published: February 2008

Using a combination of a surface energy balance equation and an approximate expression of water vapor and sensible heat transfer, an equation is formulated relating potential evaporation for net radiation, ambient air properties, and surface roughness. As an improvement over the earlier Penman version, the proposed model contains no empirical constants or functions. Tests of the model in Phoenix, Arizona, using open water, wet bare soil, and well watered alfalfa, show excellent agreement of calculated and measured values on an hourly and daily basis under a variety of circumstances. Test conditions typically included advection of sensible heat to the evaporating surface in a large proportion to the latent heat flux, as well as high values of radiant flux, ambient temperatures, and vapor pressure deficits. The use of daily average values for the weather variables in the model, rather than hourly data, did not give appreciably different results or conclusions on a series of mostly clear days, suggesting that the combination model is not only accurate but also practical and generally applicable. (Key words: Evaporation; evapotranspiration; meteorology)
On reservoir site preservation policy
Authors: Kneese Allen V.
Published: February 2008

It is often taken to be self‐evident that some sort of reservoir site preservation policy should be adopted in view of the scarcity of sites, the pressure to use them for other purposes, or the general rise in land prices. Upon further reflection, however, the issue appears to be quite complex. This comment briefly discusses possible reasons for preservation policies and assesses alternative methods for implementing them. These thoughts are directed primarily toward policies that might be adopted at the state level. It is hoped that they will stimulate further discussion of the matter.
A study of tidal dispersion in the Potomac River
Authors: Hetling L. J. , O'Connell R. L.
Published: February 2008

A dye tracer experiment was performed to determine the dispersive properties of the Potomac estuary. A fluorescent dye, Rhodamine WT, released continuously for 13 days through a submerged outfall sewer, was traced effectively over the upper 25 miles of the estuary for 34 days. Observed dye distributions were analyzed using a classical 1‐dimensional advection‐diffusion model applied to each of 16 discrete volume segments. Repetitive analog computer solution of the resulting set of 16 linear differential equations showed that dispersion coefficients increasing from 0.2 to 0.6 mi2/day in a downstream direction gave a satisfactory temporal and spatial description of the observed dye distribution. The dye loss in the estuary was found to be described by a first‐order reaction rate constant that had an upper limit of 0.034 day−1. The effect of river inflow on the distribution of a nonconservative pollutant from a point source discharge was calculated using the model.
An excessive rainfall in Panama, October 1954
Authors: Henry Walter K.
Published: February 2008

During October 1954 heavy rains, which exceeded normal by 300%, occurred in the Chiriqui province of Panama, causing extensive flooding. The copious rainfall is believed to be caused by a small tropical storm and the remnants of a polar air mass.
The temporal and spatial distribution of dissolved oxygen in streams
Authors: O'Connor Donald J.
Published: February 2008

The geophysical characteristics of the drainage basin and the biochemical and physical environment of the river affect the concentration of dissolved oxygen. These factors are embodied in the fundamental equation of continuity that describes the oxygen balance. The variation of the fresh‐water flow and cross‐sectional area is included, as well as the various sources and sinks of oxygen: natural and artificial aeration, the photosynthetic contribution, bacterial and algae respiration, carbonaceous and nitrogenous oxidation, and benthal deposits. Application of the basic equation is summarized by two general cases: the first in which bacterial respiration and spatial profiles are significant and the second in which the algae activity and the temporal changes are predominant. The equations provide technological functions for these cases to assess water quality and pollution and to determine the effect of many natural or artificial changes in the stream environment.
Some error properties of segmented hydrologic functions
Authors: Snyder Willard M.
Published: February 2008

Unknown but mathematically continuous functions can be approximated by connected linear segments. The magnitude of the largest error between segmented and continuous forms is shown to be about ⅔ of the maximum difference between arc and chord of the continuous function. This magnitude decreases rapidly with increasing number of segments. Unknown operational hydrologic functions, such as unit hydrographs or water‐yield recessions, can be derived directly from observational data by the method of least squares, and the solutions for fixed segmented systems can be standardized. The form‐free segmented functions are shown to be capable of better representation of data than incorrectly assumed continuous forms. (Key words: Hydrologic systems; water yield; unit hydrograph)
Numerical solutions for dispersion in porous mediums
Authors: Shamir Uri Y. , Harleman Dolald R. F.
Published: February 2008

A numerical method is presented for the solution of problems of dispersion in steady three‐dimensional potential flow fields in porous mediums, in which the miscible fluids have the same density and viscosity. The method is developed and tested for two‐dimensional problems, and the extension to three dimensions is presented. Emphasis is put on the efficiency of the numerical scheme and on its generality. It is shown to be independent of the geometry of the flow field. The computer program for carrying out the computations as described is tested with simple problems, for which exact or approximate analytical solutions exist. It is also used to obtain solutions to a few problems for which no other solution is known. (Key words: Dispersion; porous mediums; groundwater; pollution)
Explanation of paradoxes in Dupuit‐Forchheimer Seepage Theory
Authors: Kirkham Don
Published: February 2008

Cutting into a porous medium of a large number of vertical, parallel, infinitely permeable, equally spaced, infinitesimally thin slots produces a fictitious soil that follows, exactly and without paradoxes Dupuit's assumptions and hence Dupuit‐Forchheimer (D.F.) drainage theory in two dimensions. A soil having these infinitesimally thin slots is designated a D.F. soil. For this fictitious soil, a formula for the proper depth and spacing of ditches and drain tiles is derived. The formula is the same one found in conventional D.F. literature. The formula, valid for both tiles and ditches and known to hold approximately for actual soils, is exact for a D.F. soil. Dupuit's two‐dimensional ‘parabolic seepage problem’ and others may now be considered as exactly solvable for D.F. soils. For three‐dimensional axially symmetric seepage flow, as into wells, the fictitious slots of a DF. soil become concentric coaxial rings. DF. streamlines are not horizontal; they converge in a special way. (Key words: Drainage; groundwater; seepage; hydraulics)
Throughall and stemflow in a pine‐hardwood stand in the Ouachita Mountains of Arkansas
Authors: Lawson Edwin R.
Published: February 2008

In a pine‐hardwood stand in the Ouachita Mountains of Arkansas, throughfall was strongly correlated with gross rainfall and long‐term mean temperature on the calendar day of the storm, whereas stemflow was closely related to gross rainfall, crown diameter (or basal area at breast height), tree height, and minimum temperature on storm date. Total interception averaged 15.1% of average annual gross rainfall and stemflow 2.4%. Thus, average annual interception loss was 12.7%. Nearly 75% of total stemflow was from hardwoods, which were primarily understory trees.
The nonlinear prediction problem in the study of the runoff cycle
Authors: Amorocho J.
Published: February 2008

The general theory of nonlinear synthesis and analysis in hydrology is discussed, with particular reference to the problems of predictive uncertainty. These problems are associated with incomplete descriptions of the hydrologic systems, limited model‐prototype equivalences, system variability in time, and system nonlinearity. Solutions to the nonlinear analysis problem of hydrologic systems under the assumption of approximate time invariance, based on complex cascade network approximations, power series and polynomial expansions, and variable response function approximations are presented. The relations between present theoretical knowledge and its practical application are summarized.
Time distribution of rainfall in heavy storms
Authors: Huff F. A.
Published: February 2008

Time distribution relations have been developed for heavy storms on areas ranging up to 400 square miles and presented in probability terms to provide quantitative information on interstorm variability and to provide average and extreme relations for various applications of the findings. It was found that the relations could be represented best by relating per cent of storm rainfall to per cent of total storm time and grouping the data according to the quartile in which rainfall was heaviest. The individual effects of mean rainfall, storm duration, and other storm factors were small and erratic in behavior when the foregoing analytical technique was used. Basin area had a small but consistent effect upon the time distribution. The derived relations are applicable to the Midwest and other areas of similar climate and topography. They can be used in conjunction with published information on spatial distributions and other storm parameters to construct storm models for hydrologic applications.
Optimum density of rainfall networks
Authors: Eagleson P. S.
Published: February 2008

Techniques of harmonic analysis and the concepts of distributed linear systems are used to study the sensitivity of peak catchment discharge to the characteristic spatial variability of convective and cyclonic storm rainfall. Application of the sampling theorem leads to quantitative general relations for optimum rainfall network density for flood forecasting purposes. Specification of network density for the study of long‐term, catchment‐average rainfall is accomplished by considering the long‐term point rainfall as a homogeneous random variable to be sampled spatially. Incorporation of catchment dynamics into the design of flood forecasting networks reduces the number of gages needed when compared with that obtained solely through consideration of precipitation variability. In many studies little advantage is gained by utilizing more than two properly located stations for the determination of long‐term areal mean rainfall.
The movement of radioactive sodium and ruthenium through a simulated aquifer
Authors: Champlin J. B. F. , Eichholz G. G.
Published: February 2008

The interaction of water solutions with the particulate matter composing a natural aquifer is of steadily increasing interest with the new emphasis on pollution of our natural resources. As a means of studying the contribution made by water to the transport of ionic materials through soils, radioactive solutions were injected into a model aquifer containing 725 kilograms of sand with dimensions of 1 × 2 × 0.25 meters. As the radioactivity passed through the sand, its progress was followed by a collimated Geiger‐Müller tube situated on the exterior of the bed. The appearance of the radioactivity in the effluent, which marked the arrival of the sodium front, was found to be correlated with an increase in suspended particulate matter, potassium and calcium concentrations, and over‐all conductivity. Of particular significance was that portion of the radioactivity shown to be related directly to the filterable mass of particles in the effluent, despite the high solubility of the ion used. The results with the sodium were compared with those of similar tests on the movement of trivalent ruthenium, which is not soluble at the pH of the solutions used. Both the sodium and ruthenium studies indicated that a significant amount of radioactivity was transported through the test bed on particulate matter which was large enough to be trapped on 0.45 micron membrane filters.
Optimization of the Operation of a Multiple‐Purpose Reservoir by Dynamic Programming
Authors: Hall Warren A. , Butcher William S. , Esogbue Austin
Published: February 2008

A technique of analysis is presented by which the dynamic operation policies for planning complex reservoir systems producing hydroelectric power and providing water can be optimized for the maximum return from firm water, firm power, dump water, and dump power. The technique provides for complex constraints, such as mandatory flood control reservations variable in time, fish, wildlife, and recreational releases, navigation minimum flows, etc., as well as evaporation losses and inter‐basin diversions. The paper presents in detail the operational analysis of a component reservoir‐river system and the procedure to be used to combine optimally a number of such subsytems into a coordinated, mutually reinforcing, multiple‐river system.
The Adaptability of an Exact Solution to Horizontal Infiltration
Authors: Brutsaert Wilfried
Published: February 2008

An exact solution of the concentration‐dependent diffusion equation, which was obtained by J. R. Philip, is shown to be adaptable to the problem of horizontal infiltration into partly saturated porous materials by a suitable approximation of algebraic functions describing the moisture content‐capillary suction and the moisture content‐capillary conductivity relationships. One of the theoretical results that compares favorably with published experimental data gives the cumulative infiltration simply as

F = [2k0A(θ0 ‐ θi)/n]1/2t1/2

where k0 is the hydraulic conductivity at saturation, θ0 is the porosity or the volumetric water content at saturation, θi is the initial water content, n is the exponent in the power function of the normalized water content describing the relative permeability, and A is a characteristic length parameter depending on the fineness of the pores.
An Analysis of the Vertical Infiltration of Water into Soil Columns
Authors: Thames John L. , Evans D. D.
Published: February 2008

An experimental investigation is reported for vertical infiltration of water into a sandy loam and silt loam soil material. Water was allowed to enter air‐dry columns of soil at a small constant suction, and its subsequent distribution was followed with a gamma radiation attenuation device. An analytic expression of water content as a function of depth and time was obtained by multiple regression analysis, from which it was possible to determine the instantaneous flux and the water concentration gradient at given water contents.

The relation between the flux and gradient was linear only during the early stages of infiltration. Nonlinearity at low water gradient was evidenced for both soils throughout a wide range of water contents. The magnitude and direction of the departure from linearity were similar for both soils.

A new empirical flow equation, capable of fitting the data closely, was obtained by modifying the diffusivity equation for unsaturated flow. The modification consisted of raising the water‐content gradient to a power greater than unity. Under this modification, the parameter analogous to soil‐water diffusivity becomes a function of both water content and water‐content gradient.