ISSN:0143-1161    

DOI:10.1080/01431169108955193

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

ISSN:0143-1161    

DOI:10.1080/01431169108955194

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

This paper traces the highlights of the Seasat-A project from its earliest conceptual phases through the orbital operations phase. The primary objective of the project was to demonstrate the feasibility of remotely sensing fundamental oceanographic phenomena on a global, accurate, reliable and timely basis from an Earth-orbiting platform. The project successfully achieved its primary objective, in spite of a premature spacecraft failure, and thus provided a firm basis for the development of sensors for future ocean-observing space missions.

ISSN:0143-1161    

DOI:10.1080/01431169108955195

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The experience gained by analysing the Seasat altimetric observation of the ocean dynamic topography is getting more valuable as almost 10 years of nearly continuous altimeter data may be obtained by Geosat, ERSI and Topex/Poseidon. Our group worked on all aspects of the question: the accuracy of the measurements and more particularly the improvements of the orbit determination and its error; the extraction of the dynamic topography signal both on the mesoscale and on the large scales and of tides; the analysis of the observations, whether statistically or in the form of synoptic maps, and finally, how to constrain dynamical models from altimetry data. This paper describes these various aspects of our work.

ISSN:0143-1161    

DOI:10.1080/01431169108955196

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Some recent ocean modelling studies are reviewed which illustrate the ways in which dynamic ocean circulation models can be used to advise on the optimum deployment of, and help analyse the data from, future satellite altimeters for studies of ocean dynamics. At the time of the launch of Seasat the ocean modelling community were unaware of the promise of altimetry. It is a tribute to the enormous success of the Seasat mission that now, ten years on, the modelling community eagerly awaits the launch of a new generation of altimeters.

ISSN:0143-1161    

DOI:10.1080/01431169108955197

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

A short review is given of U.K. research into temporal variations in sea surface topography using data from Seasat and the currently operational US Navy Geosat. Investigations from Seasat have included the North Sea validation experiment, the extraction of regional and global ocean tide signals,and the study of the oceanic mesoscale. Preliminary work in progress on the first year of Geosat data is concentrated on the mesoscale variability of the north-east and south Atlantic Ocean, the latter including a comparison to sea level changes observed at the islands of Tristan da Cunha and St Helena. The future plans of the U.K. altimeter community for using ERS-I and TOPEX/POSEIDON data during the WOCE period are summarized.

ISSN:0143-1161    

DOI:10.1080/01431169108955198

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

This paper presents an overview of the research performed by the Orbital Mechanics Section of Delft University of Technology on the precise orbit computation of Seasat and the processing of the satellite's altimeter measurements. After a general description of the Seasat tracking and orbit characteristics, the applications of the altimeter data for geophysical and oceanographic investigations and as tracking data are addressed. Subsequently, the accuracy of orbit determination achieved by processing laser range data only or laser ranges in combination with altimeter height cross-over differences is discussed, and the identification of the radial orbit error from altimeter height residual profiles is described. The geographical correlation of the radial orbit error is analysed and the development of a tailored gravity model is addressed. Finally, the elimination of the residual radial orbit error is discussed and an example is given of the computation of a mean sea surface.

ISSN:0143-1161    

DOI:10.1080/01431169108955199

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

In this paper we review the physical understanding and the algorithms necessary to extract wave information from the radar altimeter return from the sea surface. This allows us to assess the progress made since the launch of Seasat, to identify areas where further work is necessary in order to develop our understanding of the basic mechanisms of radar interaction with the sea surface, and to suggest how new wave parameters might be obtained from the radar return. Following on from this were view the wave studies that have been carried out using Seasat and Geosat altimeter data and present some new results, on the joint probability distribution of significant waveheight and wind speed, which we have obtained recently from Seasat data.

ISSN:0143-1161    

DOI:10.1080/01431169108955200

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The feasibility of analysing and presenting global wave climate by fitting annual and semi-annual harmonics to monthly mean values of significant wave height in 2° x 2° bins is investigated using one year's data from Geosat (November 1986 to November 1987). Stringent checks on the data result in 16 percent being discarded. Nevertheless, the analysis is found to give a generally coherent and realistic picture. The annual component dominates in most areas, but in places the semi-annual harmonic is significant, either by itself or in conjunction with the annual cycle.

ISSN:0143-1161    

DOI:10.1080/01431169108955201

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

One of the most important measurements required from oceanographic satellites is the surface wind over the ocean. The ability of three of Seasat's microwave sensors to provide useful estimates of wind is assessed, and some examples of features in the data are described. For the scatterometer attention is focused on coastal seas which have been neglected until now in the literature. Particular problems in the retrieval of wind speed by altimeters are highlighted, including the effects of atmospheric attenuation and the need for more consistent algorithms relating the radar cross-section at nadir to the wind. The forthcoming missions ERS-1 and TOPEX/POSEIDON will provide opportunities for continued study of these issues.

ISSN:0143-1161    

DOI:10.1080/01431169108955202

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor