摘要:

An investigation of five figures commonly used in shoran trilateration resulted in numerical values expressing the relative accuracies obtainable using these figures. Triangles and quadrilaterals are examined for various shapes, while the semi‐hexagon, hexagon,‐and square are examined fixed in shape but with different locations for the fixed li

ISSN:0002-8606    

DOI:10.1029/TR034i004p00513

年代:1953

数据来源: WILEY

摘要:

This paper describes the phased‐superposed‐epoch method in which data are grouped according to their phases for analytical treatment. The phases are those of increase, decrease, or no change in geomagnetic activity, and are determined by the characteristics of pairs of days, both individually and relative to each other, on the basis of previously chosen criteria. This method is otherwise similar in some respects to the Chree superposed‐epoch method, in which the characteristics of only one day are considered in the grouping of data (selection of reference days). In a limited but demonstrative investigation, the daily magnetic C figures for 1932–1946 were classified according to their level of activity as disturbed D, intermediate I, and quiet Q. The groups of data thus referenced by the three Chree categories and by the nine phases were analyzed on punch‐card machines. Some of the results obtained by the phased method for the entire 15‐year period, considered in terms of the averaged C values, were as follows: (1) When magnetic activity remains at a generally disturbed, an intermediate , or a quiet level for at least two days, the second day tends to be slightly more quiet than the first. (2) The tendency for the magnetic activity of a sequence of two days to repeat itself after 26 to 28 days is strongest when the two days are at the same level of activity. (3) The phases that recur most strongly 26 to 28 days after their initial incidence are II, QQ, DD, and QD. (4) The phased method makes evident some trends in activity that are smoothed away or reduced in the use of the C

ISSN:0002-8606    

DOI:10.1029/TR034i004p00519

年代:1953

数据来源: WILEY

摘要:

The reality of the decrease of conductivity with height observed at the top of theExplorer IIflight is supported by some measurements made earlier by Idrac. The cause of this decrease is discussed and an hypothesis of convective updraft of Aitken nuclei from troposphere to stratosphere is examined. The hypothesis appears incapable of accounting for a steady‐state worldwide population of stratospheric nuclei sufficient to satisfy existing observations. It is urged that Idrac's measurements be repeated on a more extensive basis using more modern sounding technique

ISSN:0002-8606    

DOI:10.1029/TR034i004p00529

年代:1953

数据来源: WILEY

摘要:

This paper describes an easily constructed instrument for the purpose of obtaining a continuous record of the time of occurrence and duration of shower‐type rains and their range of raindrop sizes. A battery‐driven motor pulls paper tape, previously treated with the water‐soluble dye, methylene blue, past an opening exposed to the rain. The spot diameters left by the rain on the tape may be related to raindrop size by laboratory calibration. During a week's run on the island of Oahu, Hawaii, a total of 119 rains were recorded. Although many of these passed in a minute or so and were only a few minutes apart, less than 40 were recorded by nearby recording rain

ISSN:0002-8606    

DOI:10.1029/TR034i004p00534

年代:1953

数据来源: WILEY

摘要:

Very little is known of the natural radioactivity exhibited by continental‐shell sediments off the eastern coast of the United States. A knowledge of the level of this activity is most important if future surveys are to utilize radiometric techniques for the solution of oceanographic problems. Activities were determined for a group of samples from selected locations in the Chesapeake Bay area. The apparatus for making these measurements is described. Results are used to show the distribution of natural radioactivity in this ba

ISSN:0002-8606    

DOI:10.1029/TR034i004p00539

年代:1953

数据来源: WILEY

摘要:

Oceanographic observations made from ice floes by United States naval aircraft in 1951 and 1952 indicate that the circulation of the Polar Sea is more complicated than the cyclonic system suggested by Nansen. The chief feature observed is a large anticyclonic eddy north of Alaska. Some evidence is produced of the existence of a submarine ridge running across the center of the North Polar Basin.

ISSN:0002-8606    

DOI:10.1029/TR034i004p00543

年代:1953

数据来源: WILEY

摘要:

The steep and rugged mountains of Southern California contain considerable ground‐water storage. A large portion of the runoff is seepage from this storage The variations in runoff distribution depend on the geology, physiography, and soil cover of these mountain area

ISSN:0002-8606    

DOI:10.1029/TR034i004p00552

年代:1953

数据来源: WILEY

摘要:

This paper reports the effects of altering an aspen forest cover in Utah on evapotranspiration losses, overland flow, erosion, and mantle storage deficits during three successive growing seasons. These data, together with supplemental measures of winter precipitation and estimates of evaporation from snow, provided a basis for estimating amounts of water available for stream flow. Removal of aspen trees, leaving the herbaceous understory and litter undisturbed, reduced evapotranspiration losses and increased the amount of water available for stream flow by about four inches without seriously increasing overland flow or soil erosion during summer rains. Removal of the remaining herbaceous cover further reduced evapotranspiration losses and increased the amount of water available to streams by an additional four inches but resulted in an undesirable increase in summer rainfall runoff and soil loss.

ISSN:0002-8606    

DOI:10.1029/TR034i004p00563

年代:1953

数据来源: WILEY

摘要:

Sea water has already invaded or is an immediate or potential danger in at least 80 major and minor ground‐water basins in California. Of this total, there is definite evidence of intrusion into 13 basins and immediate danger exists in seven additional basins. Where the normal seaward hydraulic gradient has been reversed for protracted periods of time, sea‐water intrusion has occurred. Possible methods of control to restrain encroachment or reduce the area already affected include: (1) raising of ground‐water levels to or above sea level by reduction or rearrangement of pattern of pumping draft, or both; (2) direct recharge of overdrawn aquifers to maintain ground‐water levels at or above sea level; (3) maintenance of a freshwater ridge above sea level along the coast; (4) construction of artificial subsurface dikes; and (5) development of a pumping trough adjacent to the coast. The California Legislature has appropriated $750,000 for an experimental program to determine design criteria for the prevention and control of sea‐water

ISSN:0002-8606    

DOI:10.1029/TR034i004p00575

年代:1953

数据来源: WILEY

摘要:

Three precipitation‐altitude studies made cooperatively by the Tennessee Valley Authority and the U.S. Weather Bureau are discussed. In one study covering observations of a line of precipitation stations across the Great Smoky Mountains, a typical increase of rainfall with altitude is described. Results of another study, an investigation across sharp‐crested Snake Mountain, North Carolina, show precipitation at the top of the ridge to be only 70 pct of that on the slopes a short distance below the crest. A similar situation is described on Clinch Mountain in Virginia. Seasonal effects are noted, with the most pronounced differences occurring in the October–March period. The low catch at the ridgetop stations is attributed to a combination of updraft and carry‐over of moisture‐laden air because of the steep slopes and narrow crest widths of t

ISSN:0002-8606    

DOI:10.1029/TR034i004p00583

年代:1953

数据来源: WILEY