ISSN:0149-0419    

DOI:10.1080/01490417709387948

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

This paper covers the topic of marine geodesy, its goals, and applications. Specifically discussed are position determination and establishment of geodetic control on the ocean bottom, ocean surface, and subsurface, and the determination of the geoid, a vertical reference surface. The various techniques used in position determination (including satellite, airborne, radio, inertial and acoustic techniques) are assessed in terms of accuracy, coverage, and contribution to the solution of specific problems associated with position and control. The results of several marine geodetic control experiments are presented. Classical techniques for the determination of the geoid are discussed and assessed, as are new techniques such as satellite altimetry. The outlook for marine geodetic measurements in the ocean is outlined in terms of what is being planned or considered for the next decade, and several recommendations are made.

ISSN:0149-0419    

DOI:10.1080/01490417709387949

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

The current ambition to achieve a 10‐cm marine geoid focuses attention on the interdisciplinary problem of relating oceanographic to geodetic measurements, and on the apparent conflict between them along the United States’ coasts. The concepts underlying the comparisons in this conflict are analyzed, and shown to leave a possibility of diffusing the deadlock by more precise reformulations. Concepts which have been equated in practical applications under less stringent accuracy requirements need to be refined and related more precisely through interdisciplinary efforts. An example is given of a geodetic utilization of density differences in the ocean, akin to but not the same as the idea of steric leveling, in order to highlight the similarity and dissimilarity between some geodetic and oceanographic ideas.

ISSN:0149-0419    

DOI:10.1080/01490417709387950

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

For navigation in deep ocean the most important navaids are self contained dead reckoning systems (DRS) such as classical DRS with log and compass or Doppler‐DRS or inertial navigation system (INS) and the external radio navaids LORAN, Omega and Navy Navigation Satellite System (NNSS). These navaids cannot satisfy the requirements for precise surveying if they are used in the conventional manner. Accuracy can be increased by integration of the DRS with the external navaids by a computer which estimates best values of position, velocity, etc. from all available data. The DRS is used as reference system and the external navaids are used for control measurements. The measurements are compared with the same quantities computed from the positions, which are indicated of the DRS. The differences between the measured and the computed values are described by error models of the integrated navaids and processed by a filter to estimate best values of the errors of the DRS and to make corresponding corrections. The principles of least square filtering are described in detail for integrated Inertial/LORAN‐C and Inertial/Omega navigation.

ISSN:0149-0419    

DOI:10.1080/01490417709387951

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

The dynamics of tsunamis can be divided, for convenience, into three parts: tsunami generation, tsunami propagation, and the coastal problems. Out of these three, the problem of tsunami propagation is probably better understood than the other two. One of the main hindrances to the quantitative prediction of tsunami amplitudes at various coastal locations is a lack of detailed knowledge about the deep water signature of a tsunami. Here, the present understanding of this problem is discussed.

ISSN:0149-0419    

DOI:10.1080/01490417709387952

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Western boundary currents, such as the Gulf Stream, are often modeled as flows in near cross‐stream geostrophic balance with paths that are straight or nearly straight. The effect of planetary vorticity advection on the downstream sea‐level slope in these rectilinear flows is re‐examined and found negligible. Instead, the re‐examination reveals a much greater effect of the ageostrophic component of the horizontal divergence in determining the downstream slope. Overlooked in previous studies is the geostrophic component of the horizontal divergence because of a hidden assumption of parallel flow. To avoid this pitfall, we employ a natural coordinate system to follow precisely the downstream direction. Further, we differentiate between weak geostrophic flows with small accelerations and flows in cross‐stream geostrophic balance where downstream acceleration might be appreciable. Two Rossby numbers are employed: a small cross‐stream number (≤0.01) to describe the near cross‐stream balance, and a large downstream number (≤0.1) to describe the large downstream accelerations that are found in western boundary flows. Finally, by means of a scale analysis we show that over the whole range of possible Rossby numbers, the advection effect of planetary vorticity on downstream sea level slope is negligible compared to the effect of the ageostrophic component of the horizontal divergence. Some new data on the nearshore gradient of the Reynolds stress are also included.

ISSN:0149-0419    

DOI:10.1080/01490417709387953

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Sea Surveying,edited by Alan Ingham (London: John Wiley & Sons, 1975), 2 volumes, 306 and 233 pp., hardcover, $49.50.

ISSN:0149-0419    

DOI:10.1080/01490417709387954

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

ISSN:0149-0419    

DOI:10.1080/01490417709387955

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

ISSN:0149-0419    

DOI:10.1080/01490417709387947

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor