摘要:

The determination of sea surface topography requires two types of measurements: one to obtain the mean sea surface, the other to obtain the geoid. While precise altimetry can be used for the first purpose, gradiometry seems at present to be the only efficient method to resolve the short wavelengths of the geoid beyond the mean sea surface approximation. The potential of this new technique for sea surface topography determination is treated in this paper. A brief description of the different gradiometer prototypes and proposals leads to a discussion of the spectral characteristics of the measured second‐order gradients. Special emphasis is given to the attenuation of the anomalous gravitational spectrum with height and the consequences this has for recovering those frequencies that are important for geoid determination. Results indicate that a resolution of the geoid below the 10‐cm level can be achieved by combining airborne gradiometry with a high order reference field, which could be obtained by either satellite‐to‐satellite tracking or satellite gradiometry.

ISSN:0149-0419    

DOI:10.1080/15210608109379401

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

ISSN:0149-0419    

DOI:10.1080/15210608109379400

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The interaction between astronomical tides and storm surges in two different water bodies, namely the St. Lawrence estuary and the Suez Canal, is studied using simple analytical theories. Two parameters were derived that are of fundamental importance to this interaction. Based on the values of these parameters one should be able to determine with which state of the tide (rising, high, falling, low) the maximum surge should be associated.

ISSN:0149-0419    

DOI:10.1080/15210608109379402

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

A fortnightly modulation in daily‐mean sea level observed in shallow rivers has been associated with the rectifying action of frictional forces. Using data from the Severn River, where this phenomenon is observed, it is shown by an order‐of‐magnitude calculation that the presence of a tidal bore occurring around spring tides makes only a very small contribution to the fortnightly modulation.

ISSN:0149-0419    

DOI:10.1080/15210608109379403

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

In 1974 and 1975 pressure gauges were placed on and records recovered from Union Seamount (49°35'N, 132°47'W), Bowie Seamount (53°18'N, 135°37'W), and Surveyor Seamount (56°08'N, 144°22'W) in the Northeast Pacific in depths of 314, 170, and 630 m, respectively. These records have been analyzed to derive harmonic constituents, and co‐phase and co‐amplitude charts have been prepared for the neighboring regions. Maximum tidal range observed was 4 m. The temperature recorded by the gauge on Surveyor Seamount revealed a predominantly semidiurnal signal of range 0.1 Celsius degree, which represents a vertical displacement of the water column of up to 50 m. Significant diurnal oscillations are not present in the temperature record. The pressure record at Union Seamount was low‐pass filtered to attenuate tidal signals. The residual pressure fluctuations at Union Seamount were up to 12 mbars in range, about one fifth of the range of the local sea‐level atmospheric pressure fluctuations. The ocean surrounding Union Seamount behaves largely as an inverted barometer, with evidence of an undershoot at periods near four days.

ISSN:0149-0419    

DOI:10.1080/15210608109379404

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The problem of detecting tsunamis and measuring their wave‐height in the deep ocean has been investigated theoretically by Saxena (1974, 1975, 1976, 1978). This paper is a continuation of the earlier investigations and describes a system for measuring tsunami wave‐heights in the deep ocean. This cableless system uses pressure sensors, a two‐way digital acoustic telemetry system buoy, and a stationary satellite. The measured tsunami wave‐height and its direction of propagation will be an added parameter to the existing tsunami warning system, which will improve the reliability of tsunami warnings.

ISSN:0149-0419    

DOI:10.1080/15210608109379405

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

ISSN:0149-0419    

DOI:10.1080/15210608109379406

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The development of manned deep‐sea submersibles equipped with a sampling device was a milestone in oceanographic research comparable to the development of the Precision Depth Recorder and the Profiler. Visual observations in deep trenches will contribute significantly to solving some basic problems of the formation of our planet such as “Is the earth expanding, shrinking, or maintaining a steady size?”; The occurrence of oil within the deep trenches is not outside the realm of possibility. The movie, ‘'Chasms Beneath the Sea,”; is a memorial to Dr. Bruce C. Heezen, who made many contributions to understanding the structure and processes of the ocean basins, as well as pioneering in the use of deep‐sea submersibles.

ISSN:0149-0419    

DOI:10.1080/15210608109379407

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

ISSN:0149-0419    

DOI:10.1080/15210608109379408

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

ISSN:0149-0419    

DOI:10.1080/15210608109379409

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor