Dispersal in shallow seas inferred from remotely-sensed infra-red imagery
Dispersal in shallow seas inferred from remotely-sensed infra-red imagery
This work is an attempt to apply remotely-sensed infra-red radiance measurements to the study of dispersal processes in the shallow, tidally-dominated regime of the English Channel and Southern Bight. Various deficiencies inherent in raw imagery from the spaceborne Advanced Very High Resolution Radiometer (AVHRR) are identified and the corresponding corrective strategies reviewed and discussed. In particular, an algorithm to map an arbitrarily orientated image onto a standard geographical grid is developed and included as part of an integrated processing shceme which produces maps of sea-surface temperature from the content of the AVHRR data stream. The sea-surface temperature patterns thus obtained are then applied to a two dimensional finite-difference model of the advective-diffusive processes occurring over the winter of 1983-84, an interval which coincides with a good time series of satellite imagery. By matching the model-predicted thermal fields at various stages during the integration of the corresponding observed fields, the degrees of success of adopting one of a number of parameterisations of horizontal mixing is assessed. The theoretical work of Bowden (1965) and observational results of Talbot and Talbot (1974) suggest that horizontal mixing in this region may be due, in large part, to the interaction of turbulent vertical eddies and vertical shear in the tidal streams. Here, Bowden's method is extended to the case of a two-dimensional tidal current vector which varies in time. This provides one possible mechanism for mixing and it is compared by means of the model results with others which assume (a) no diffusion and (b) diffusion due to horizontal eddies with various typical length-scales. The shortcomings of the model results are assessed in the light of inadequacies in the meteorological data used for calculating the surface heat fluxes; it transpires that these fluxes strongly influence not only the gross temperature of the basin but also the spatial structure of the thermal field. The simulated results of an instantaneous tracer discharge in the Dover Straits under varying dispersal conditions are also prevented. (D74414/87)
University of Southampton
1986
Daniels, John Wyn
(1986)
Dispersal in shallow seas inferred from remotely-sensed infra-red imagery.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
This work is an attempt to apply remotely-sensed infra-red radiance measurements to the study of dispersal processes in the shallow, tidally-dominated regime of the English Channel and Southern Bight. Various deficiencies inherent in raw imagery from the spaceborne Advanced Very High Resolution Radiometer (AVHRR) are identified and the corresponding corrective strategies reviewed and discussed. In particular, an algorithm to map an arbitrarily orientated image onto a standard geographical grid is developed and included as part of an integrated processing shceme which produces maps of sea-surface temperature from the content of the AVHRR data stream. The sea-surface temperature patterns thus obtained are then applied to a two dimensional finite-difference model of the advective-diffusive processes occurring over the winter of 1983-84, an interval which coincides with a good time series of satellite imagery. By matching the model-predicted thermal fields at various stages during the integration of the corresponding observed fields, the degrees of success of adopting one of a number of parameterisations of horizontal mixing is assessed. The theoretical work of Bowden (1965) and observational results of Talbot and Talbot (1974) suggest that horizontal mixing in this region may be due, in large part, to the interaction of turbulent vertical eddies and vertical shear in the tidal streams. Here, Bowden's method is extended to the case of a two-dimensional tidal current vector which varies in time. This provides one possible mechanism for mixing and it is compared by means of the model results with others which assume (a) no diffusion and (b) diffusion due to horizontal eddies with various typical length-scales. The shortcomings of the model results are assessed in the light of inadequacies in the meteorological data used for calculating the surface heat fluxes; it transpires that these fluxes strongly influence not only the gross temperature of the basin but also the spatial structure of the thermal field. The simulated results of an instantaneous tracer discharge in the Dover Straits under varying dispersal conditions are also prevented. (D74414/87)
This record has no associated files available for download.
More information
Published date: 1986
Identifiers
Local EPrints ID: 461139
URI: http://eprints.soton.ac.uk/id/eprint/461139
PURE UUID: 4b8caca3-b839-497e-9f9c-316b2a41f7d5
Catalogue record
Date deposited: 04 Jul 2022 18:36
Last modified: 04 Jul 2022 18:36
Export record
Contributors
Author:
John Wyn Daniels
Download statistics
Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.
View more statistics