摘要:

The Central Land Surveying Bureau of China established several arcs of principal triangulation during 1932–37. Those which were completed before the outbreak of the war in July, 1937, are Nanking‐Anking, Nanking‐Hsüchow, Anking‐Nanchang, Nanchang‐Kiukiang, and Anking‐Wuchang arcs.At the end of each arc, a base line was measured with invar tapes or wires and an astronomical station at which latitude, longitude, and the azimuth to an adjacent station were determined by astronomical observations. The methods used in the astronomical determinations were the same as those used by the United States Coast and Geodetic Survey, that is, latitude by the Talcott method, longitude by wireless time‐signals, and azimuth by observing Polaris. The probable errors of these astronomical determinations were below ±0.″1 for determinations of latitude, ±0.″1 for determinations of longitude, and ±0.″4 for det

ISSN:0002-8606    

DOI:10.1029/TR027i005p00619

年代:1946

数据来源: WILEY

摘要:

The method of azimuth determination from non‐circumpolar stars near elongation is described, and a series of determinations by this method is compared with a series of azimuth determinations obtained from Polaris observations. The tentative conclusion is that the two methods are comparable in precisio

ISSN:0002-8606    

DOI:10.1029/TR027i005p00627

年代:1946

数据来源: WILEY

摘要:

Latitude and longitude obtained using a pendulum astrolabe are compared with those obtained using standard United States Coast and Geodetic Survey methods. The conclusion is that the latitude is comparable in precision, but that the pendulum astrolabe longitude is subject to a systematic error probably due to personal equation.

ISSN:0002-8606    

DOI:10.1029/TR027i005p00629

年代:1946

数据来源: WILEY

摘要:

Determinations of the velocity of P1the direct longitudinal wave through the outermost or granitic layer, have been made by a number of investigators from studies of earthquake records and from timed artificial explosions. In general, the velocity of P1has been reported as about 5.5 km/sec from the former and six km/sec from the latter. Gutenberg recently discussed this difference to explain his belief that explosion waves do not give the correct picture.Gutenberg's suggestions are analyzed, and the entire problem is reviewed in the light of new evidence that personal factors of interpretation have been leading to divergence of results which is more apparent than real.It is concluded that Gutenberg's Py, for which velocities have been found between 5.92 and 6.14 km/sec, actually meets the criteria for P1and is the phase observed from 0–110 km as the first arrival on explosion records. Such an interpretation fuses earthquake studies and explosion results into a strong unified body of data establishing the velocity of P1as in the neighborhood of six km/se

ISSN:0002-8606    

DOI:10.1029/TR027i005p00631

年代:1946

数据来源: WILEY

摘要:

Preliminary tests made to determine the response characteristics of‐an electronic earthquake recorder are described. Tests were conducted with a Wenner and a special seismometer as well as with a Neumann‐LaBarre vibration meter. Simultaneous recordings on both smoked paper and photographic paper, which were made on the same drum and from the same seismometer mirror, are shown. The electronic recorder appears to respond satisfactorily to earthquake waves of from one sec to 30 sec or longer in per

ISSN:0002-8606    

DOI:10.1029/TR027i005p00636

年代:1946

数据来源: WILEY

摘要:

The approach of a tropical cyclone is usually accompanied by intensification of circulation aloft in the broad currents on its poleward side. Anticyclogenesis usually occurs downstream from the cyclone, the so‐called steering wedge tending to grow and extend westward, which tends to perpetuate the normal westward movement of the storm. The results of this study indicate that the steering level is determined by the height to which the storm s vortical circulation extends, being located approximately at the elevation where closed isobars over the storm disappear. This level ranges from below 10,000 ft to above 50,000 ft and may vary more than 10,000 ft in 24 hours. For this reason no single level can be used to determine the steering of the storm from day to day. It has been found, however, that changes occurring in the flow patterns of the 20,000‐foot, or 500‐mb, chart are excellent indices to critical changes in movement.A new tool for forecasting direction of movement for tropical cyclones has recently been developed which is apparently more valuable and effective than steering‐level analyses. By using charts of the difference in height between the 700 mb and 500 mb levels (mean virtual temperature charts), or of the weight in millibars of the layer from 10,000 to 20,000 ft, it has been found that a tongue of warmer, lighter air is associated with the moving storm. This tongue is oriented with its major axis parallel to the movement of the cyclone. An excellent lag correlation exists, such that the orientation of the tongue at any instant usually indicates the direction of cyclone movement for the ensuing 24‐ho

ISSN:0002-8606    

DOI:10.1029/TR027i005p00641

年代:1946

数据来源: WILEY

摘要:

Electrical means for eliminating count duplication when recording wind direction, by means of counters, isoklnetically or isotemporally, are here outlined.

ISSN:0002-8606    

DOI:10.1029/TR027i005p00656

年代:1946

数据来源: WILEY

摘要:

Whenever two tropical cyclones appear simultaneously in the same region, it is observed that they move around and approach each other in a characteristic fashion. In order to explain this relative motion it is assumed that the cyclones can be approximated by simple vortices. The motion of a vortex pair is studied theoretically, and it is shown that the vortices must rotate around a common center of gravity whose position is determined by the circulation around each vortex. The angular velocity of the axis of the vortex pair is equal to the arithmetic mean of the angular velocities with which the two vortices rotate relative to each other.

ISSN:0002-8606    

DOI:10.1029/TR027i005p00658

年代:1946

数据来源: WILEY

摘要:

Methods and equipment for incneasing the accuracy of wind‐speed measurements, particularly at low speeds, are here outline

ISSN:0002-8606    

DOI:10.1029/TR027i005p00659

年代:1946

数据来源: WILEY

摘要:

Equations given by W. Zenker in the last decade of the Nineteenth Century and later modified by other authors, characterizing the degree of continentality at a given place have the general form:k = mA/sin ϕ + n:where k = the continentality coefficient in per cent, A = average annual range of temperature at a given place, ϕ = geographical latitude, and m and n are constant

ISSN:0002-8606    

DOI:10.1029/TR027i005p00663

年代:1946

数据来源: WILEY