摘要:

A simple form of saturated‐core induction‐type magnetometer is described and the principle of its operation is briefly discussed. This version of the instrument employs no electronic components. Possibility of its application as a universal instrument for geomagnetic measurements is sugges

ISSN:0002-8606    

DOI:10.1029/TR027i001p00049

年代:1946

数据来源: WILEY

摘要:

Constructional details and results of tests of an induction‐magnetometer for measuring all components of the geomagnetic field are discussed. Standardization through preliminary base‐line values at the Cheltenham Magnetic Observatory, obtained with the Carnegie Institution of Washington sine‐galvanometer, show only small corrections to the computed constants in all elements. Largest corrections appear in Z and F. If base‐line values are obtained by the induction‐magnetometer and the magnetograms used only to tie in measurements of different elements, the value of F as observed differs by only two gammas from that computed from the observed values o

ISSN:0002-8606    

DOI:10.1029/TR027i001p00053

年代:1946

数据来源: WILEY

摘要:

The seasonal changes in diurnal variation at Tucson, Arizona, are of unusual interest because of its location in the transition‐belt where the type of diurnal variation changes markedly during the year. Monthly hodograms of the diurnal variation in Earth‐current potential‐gradient indicate that its changes are generally consistent with the recognized movement of the current systems in the ionosphere northward and southward with the sun. Two definite anomalies, less readily explained, are found to exist. The first is a marked increase in activity in January, which appears as a large increase in amplitude, and the second consists of a decrease and irregularity in the eastward component during

ISSN:0002-8606    

DOI:10.1029/TR027i001p00059

年代:1946

数据来源: WILEY

摘要:

The flow, in the Bosporus is normally from the Black Sea to the Sea of Marmara. This occurs a high percentage of the time. Data gathered in connection with this study show that a drop from the Black Sea to the Sea of Marmara up to 1.5 feet or even more produces this flow. Occasionally, however, due to the effects of strong south winds, there is a reversal of the gradient, and the flow is from the Sea of Marmara to the Black Sea. Possibility of density‐currents, caused by the differences of salinity of the Black Sea and the Sea of Marmara, is touched, and other phenomena related to the Bosporus are mentioned briefl

ISSN:0002-8606    

DOI:10.1029/TR027i001p00061

年代:1946

数据来源: WILEY

摘要:

A graphic method of studying the frequency of recurrence of runoff peaks has been applied to the short‐period records from a number of small agricultural areas. The study shows that for periods as short as two to six years, a consistent pattern of runoff behavior is evident for the data available. The analysis of the data, by this method, for three watersheds in the common three year rotation of corn, grain, and hay, indicates a marked increase in magnitude of runoff peaks where tillage, considerably off the contour, is practiced, compared with contour strip cropping. Where diversion terraces are used in conjunction with the rotation contour cropping, a decrease in the number and magnitude of peak flows is indicated. This is due largely to the channel storage in the terrace which spreads out and reduces the peaks and delays the runoffFor pastured areas, the data show that the maintenance of good turf on the areas is essential, particularly in winter. The addition of pasture contour furrows definitely changed the runoff pattern and resulted in a marked reduction in runoff for smaller, low intensity rains. For the larger rains, the reduction in runoff by the furrows decreases as the depth or intensity of the rainfall increasesIn general, it appears that short‐period records of runoff can be classified on the basis of frequency of recurrence and serve as a guide in making recommendations as to runoff expectancy under similar land managements and conditions. This method of determining the frequency of any runoff magnitude directly is considered superior to other methods where runoff values are first related to the rainfall that produced them and the determination of runoff frequency is then attempted from rainfall records that are available for longer periods. The advantage of the present method is obvious when it is remembered that rainfall intensity and amount are but two elements in the production of runoff, whereas this method actually measures the distribution of runoff frequencies and takes into account the effect of other watershed characteristics such as length and degree of slope; drainage pattern; size and shape of area; cover; soil type, depth, and condition; and tillage practices. The consistency that is apparent in the plotting of the data indicates that short records may be employed to characterize runoff behavior, and while data for longer periods unquestionably are needed, the direct use of such records should not be overlooked and at present may offer the best method of obtaining usable informat

ISSN:0002-8606    

DOI:10.1029/TR027i001p00069

年代:1946

数据来源: WILEY

摘要:

The derivation of the BOWEN equation for the ratio of convective and evaporative heat transports, is expressed in terms of modern turbulence‐theory. All objections to the equation which have thus far come to the writer s attention are examined. Some of these objections turn out to be nothing but misapprehensions, while the others correspond to quantities of energy which, though indeterminate, are shown to be so small as not to require attention in the practical application of the energy equations to the problem of evaporation from a continuous water‐surface. Incidentally, a rational method of using turbulence‐theory without the aid of energy relations is suggested.A mistake in computation in the report of the Bear Lake investigation published in 1940 is corrected. The average seasonal loss for the lake is reduced from 0.58 cm/day to 0.48 cm/day.The energy point of view is shown to be characterized by a degree of directness and simplicity which has thus far never been obtained in any other way, except by calculation from gage heights, which is seldom possible.Pan‐records are valuable provided those characteristics of the pan are known which determine heat‐leakage through the walls and bottom. There appears to be no experimental or observational evidence against the validity of the BOWEN equation. There is such evidence in

ISSN:0002-8606    

DOI:10.1029/TR027i001p00081

年代:1946

数据来源: WILEY

摘要:

The design of drainage facilities for agricultural land requires quantitative evaluation of (1) the water involved; (2) the permeability of the materials through which the water flows; (3) the dimensions of the aquifer; and (4) the position of the water table. This paper details techniques utilized in the determination of the coefficient of permeability in the laboratory and in the field. It further presents the need for rapid techniques of indirect determination of permeability, but recognizes the limitations of this method. The application of the coefficient of permeability in the analysis of a drainage problem or facility is outlined, and a formula for the spacing of tile‐drains utilizing the coefficient of permeability is presente

ISSN:0002-8606    

DOI:10.1029/TR027i001p00095

年代:1946

数据来源: WILEY

摘要:

Explorers began to push into the vast uncharted areas of the West in 1804, when Captains Lewis and Clarke ascended the Missouri River, crossed the Rocky Mountains into the headwaters of the Columbia River, and followed that stream to the Pacific Ocean. The honor of being the first white man to see Great Salt Lake is claimed for a number of explorers and trappers who visited the region in the twenties and thirties of the Nineteenth Century. Among these were Etienne Provot and James Bridger, who were in the region in 1824–25, each quite unaware of the other's activities and discoveries.In 1833 Captain B. L. E. Bonneville dispatched a party from his camp at Green River, Wyoming, for the purpose of exploring Great Salt Lake. This party attempted to make a circuit of the lake, chart its outline, and trap all the streams en route, but the attempt was abandoned because the great barren salt plains west of the lake were so hazardous that the party was in grave danger of perishin

ISSN:0002-8606    

DOI:10.1029/TR027i001p00103

年代:1946

数据来源: WILEY

摘要:

Between November, 1941, and February, 1944, no fewer than 110 crossings of Lake Michigan were completed, on which about 2,000 bathythermograph soundings and innumerable meteorological observations were made. Eighty of the crossings were between Milwaukee, Wisconsin, and Muskegon, Michigan, at intervals averaging about ten days. The other crossings were made to the north or west of Frankfort, Michigan.Lake Michigan essentially consists‐of two basins, the southern basin being nearly circular with a maximum depth of 172 meters. The north basin occupies the northern two‐thirds of the lake proper, is long and narrow, and has a maximum depth of 282 meters. At the speed of the vessels from which the soundings were made, the bathythermograph, recording temperatures continuously, would descend vertically not more than 105 meters. Soundings to the bottom could be taken virtually all the way across the lake between Milwaukee and Muske

ISSN:0002-8606    

DOI:10.1029/TR027i001p00109

年代:1946

数据来源: WILEY

摘要:

At the outbreak of the war, the collection, correlation, and administration of the Hurricane Weather Service was in the hands of the United States Weather Bureau, assisted by weather‐reports as practicable from the Army Air Forces and the United States Navy. However, the Hurricane Weather Service felt keenly the lack of usual weather‐reports because wartime‐restrictions, with radio silence on ships, and with ships proceeding in convoys rather than at random over the ocean, had deprived weather‐forecasters of weather reports over vast ocean‐areas which were normally obtained from merchant‐ships and other sources.The absence of these reports from ships at sea had left unreported vast expanses of ocean where destructive storms might easily form and attain dangerous proportion. Thus, wartime‐demands for accurate aerological data over these vast expanses created a problem of major proportions for the Armed Forces and the United States Weather Bureau. The Joint Meteorological Committee, a working sub‐committee for the Joint Chiefs of Staff, conside

ISSN:0002-8606    

DOI:10.1029/TR027i001p00111

年代:1946

数据来源: WILEY