摘要:

Tables are provided for facilitating the computation of the tidal acceleration of the Sun and Moon at a point on the surface of a rigid Earth. Without interpolation, the tables provide an accuracy of one microgal in the resultant computation. Higher accuracy is readily obtained by interpolation.

ISSN:0002-8606    

DOI:10.1029/TR035i002p00193

年代:1954

数据来源: WILEY

摘要:

During the winter of 1949–1950 data on depth and density of snow on the ground near Barrow, Alaska, revealed two to four times as much water equivalent as was recorded with the standard eight‐inch precipitation gage of the U.S. Weather Bureau. Indirect evidence on summer precipitation supports the conclusion that precipitation is greater than recorded. Wind effects are believed to be responsible for the difference in water equivalents and for an annual efficiency of the gage of 25 to 50 pct. Total precipitation thus may be more than 16 inches instead of about four inches as recorded. Other Arctic stations in windy areas doubtless are similarly affec

ISSN:0002-8606    

DOI:10.1029/TR035i002p00203

年代:1954

数据来源: WILEY

摘要:

Measurements by the authors of the natural radioactivity of rain water are reported. The radioactivity varied from one to 60 millimicrocuries per liter of rain water and was due primarily to RaB+C, The activities due to ThB and RaD were less than 10−10and 10−11curie per liter each, respectively. RaA is present in rain water at the time it reaches the Earth's surface. The mechanism for the accumulation of decay products in rain water is discussed. The total activity (per unit area and time) increases toward the limiting value determined by the supply of RaA from Rn. An average atmospheric Rn concentration within the cloud system of approximately 0.2×10−13curie per liter is sufficient to supply the rain water with the observed radioactivity. The natural radioactivity of the atmosphere can be used as a tracer to study meteorological phe

ISSN:0002-8606    

DOI:10.1029/TR035i002p00208

年代:1954

数据来源: WILEY

摘要:

Secchi disk readings off Southern California show a close relationship of water transparency to supply of detrital and, to a lesser extent, organic sediment along the mainland and island shores and to organic production in a large area of upwelling near the continental slope.

ISSN:0002-8606    

DOI:10.1029/TR035i002p00217

年代:1954

数据来源: WILEY

摘要:

The Puerto Rico Trench extends for about 400 mi in a generally east‐west direction 80 mi north of Puerto Rico and has a five to ten‐mile wide “flat” floor 4350 fm deep. The Trench is separated from the Nares Basin to the north by a 2900‐fm divide, and is roughly paralleled to the south by a series of seamounts which form an interrupted ridge from 2700 to 3700 fm deep. South of this ridge are basins, 4000 to 4100 fm deep, which may drain into the Trench through San Juan Canyon. The Trench floor has two kinds of sediment in alternating layers up to several meters thick: (1) layers of abyssal red clay with low carbonate content, which is “mormal” at this great depth, and (2) anomalous layers of highly calcareous sands showing excellent graded bedding and shallow water benthonic fossils. The layers of anomalous sand are attributed to the action of turbidity currents, which may have transported the sediment from neighboring island platforms down submarine canyons and deposited it in the Trench, rather than to former shallow water conditions

ISSN:0002-8606    

DOI:10.1029/TR035i002p00221

年代:1954

数据来源: WILEY

摘要:

Ground rainfall intensities and throughfall were measured under a fully‐stocked hardwood forest in West Virginia over a period of one year. Maximum 5‐ and 15‐min intensities were compared with similar measurements made in the open. The results were analyzed separately for winter and summer conditions; that is, bare canopy versus canopy in full leaf. Regression equations were calculated for estimating intensities and throughfall under canopy from rainfall measurements made in the open. The study shows that low rainfall intensities are reduced more by summer canopy, and high intensities are reduced more by winter canopy. Throughfall is reduced by canopy interception approximately the same amount in both summer and w

ISSN:0002-8606    

DOI:10.1029/TR035i002p00226

年代:1954

数据来源: WILEY

摘要:

The problem is analyzed in analogy with that of sediment transport and is partially solved. While it has not been possible as yet to predict the air content of the mixture for a given state of flow or of turbulence, the vertical distribution of air in a turbulent water mass was found to follow the laws of suspension. The change of the average flow velocity and flow depth of an open channel flow involving air‐water mixtures was predicted theoretically as a function of the air concentration. The predicted relationship was checked by measurements in model channel

ISSN:0002-8606    

DOI:10.1029/TR035i002p00235

年代:1954

数据来源: WILEY

摘要:

One of the very obvious geologic phenomena that is continuously in operation throughout the Earth's land surface is erosion, the process of wearing away the soil or the surface mantle. The falling of rain drops on an unprotected slope, the flow of water across land or in a channel, the borings of a rodent, the expansion of a root, the pull of gravity, the gouging of a glacier, or the impinging of wind on an open surface are some of the forces continually at work in this erosion process. The tendency of these forces is to bring everything to a common level and the moment a point of land or a continent rises above its surroundings, gravity, rain, wind, and all the other forces set to work, bringing it back to the level of its nieghbor. The poetic expression “the everlasting hills” is an illusion, for these erosion forces have been operative since the dawn of geologic history and the evidence is conclusive that in this sequence of time numerous generations of hills and mountain ranges have been uplifted and then razed by erosion, the waste and rock debris of one range forming the source material for its successor. We could not have the great deposits of alluvium and the thick beds of conglomerate, sandstones, and shales that occur at present throughout the Earth without erosion to furnish the source mater

ISSN:0002-8606    

DOI:10.1029/TR035i002p00243

年代:1954

数据来源: WILEY

摘要:

The question is raised whether soil erosion has ever been a serious problem on the karstic formations in the Mediterranean area. Some of the soil and water conservation practices of the Romans are described, as well as the present practices and organizations in a number of countries in the middle and eastern Mediterranean region.

ISSN:0002-8606    

DOI:10.1029/TR035i002p00244

年代:1954

数据来源: WILEY

摘要:

The principal types of water erosion on non‐irrigated agricultural lands are described. A generalized soil erosion map indicating extent and degree of erosion is presented. Selected summary data on rates of soil loss from 0.01‐acre plots in grasses, continuous row crops, and adapted crop rotations are given from nine experiment stations in important farming areas. Factors influencing rates of erosion are enumerated and discussed briefly. The objective of erosion control on agricultural lands is specified and some of the methods and principles of erosion control are lis

ISSN:0002-8606    

DOI:10.1029/TR035i002p00246

年代:1954

数据来源: WILEY