Satellite remote sensing of phytoplankton pigments in the unwelling system of Western Iberia
Satellite remote sensing of phytoplankton pigments in the unwelling system of Western Iberia
For this study a data base of vertical distributions of chlorophyll in the upwelling system of Western Iberia has been collected for analysis. The observed profiles have been fitted with a Gaussian model and the range of variability of the parameters defining the Gaussian curve derived. The pigment concentration as would be measured by a satellite was calculated numerically for the range of observed profiles and a new interpretation of the satellite estimation has been obtained. This new approach provides a physical interpretation of the satellite estimation as an increasing function of the maximum pigment concentration within the vertical distribution. The relationship is expressed as the linear function Cf = m Chlm + b, where Cf is the satellite observation and Chlm is the maximum pigment concentration. The slope m and offset b are expressed as functions of the other features of the vertical distribution, namely the depth where the maximum concentration is located, the spread of the increased concentration and a background concentration.
Although the relationship above provides a meaningful interpretation to satellite measurements, independent information about the vertical profile is still required to obtain m and b. A numerical model of the growth and vertical distribution of phytoplankton for this upwelling system has been developed to meet this requirement. The model, which selects between light or nutrient limitation of growth according to a threshold hypothesis and uses the Nitrogen cell-quota to control growth, nutrient uptake, sinking and the chl:carbon ratio, successfully reproduces the patterns of phytoplankton distribution in the region.
A case study is presented where the whole scheme to reconstruct the vertical distribution of phytoplankton is applied. Satellite ocean colour data is complemented with satellite SST data to assess upwelling conditions and residence time of upwelled waters. This is achieved by using a recent one dimensional model of the upper ocean forced by realistic atmospheric data.
University of Southampton
1998
Ballestro, Daniel
(1998)
Satellite remote sensing of phytoplankton pigments in the unwelling system of Western Iberia.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
For this study a data base of vertical distributions of chlorophyll in the upwelling system of Western Iberia has been collected for analysis. The observed profiles have been fitted with a Gaussian model and the range of variability of the parameters defining the Gaussian curve derived. The pigment concentration as would be measured by a satellite was calculated numerically for the range of observed profiles and a new interpretation of the satellite estimation has been obtained. This new approach provides a physical interpretation of the satellite estimation as an increasing function of the maximum pigment concentration within the vertical distribution. The relationship is expressed as the linear function Cf = m Chlm + b, where Cf is the satellite observation and Chlm is the maximum pigment concentration. The slope m and offset b are expressed as functions of the other features of the vertical distribution, namely the depth where the maximum concentration is located, the spread of the increased concentration and a background concentration.
Although the relationship above provides a meaningful interpretation to satellite measurements, independent information about the vertical profile is still required to obtain m and b. A numerical model of the growth and vertical distribution of phytoplankton for this upwelling system has been developed to meet this requirement. The model, which selects between light or nutrient limitation of growth according to a threshold hypothesis and uses the Nitrogen cell-quota to control growth, nutrient uptake, sinking and the chl:carbon ratio, successfully reproduces the patterns of phytoplankton distribution in the region.
A case study is presented where the whole scheme to reconstruct the vertical distribution of phytoplankton is applied. Satellite ocean colour data is complemented with satellite SST data to assess upwelling conditions and residence time of upwelled waters. This is achieved by using a recent one dimensional model of the upper ocean forced by realistic atmospheric data.
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Published date: 1998
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Local EPrints ID: 463409
URI: http://eprints.soton.ac.uk/id/eprint/463409
PURE UUID: eefe2579-8b1f-4510-8f33-ac6d52ddfc00
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Date deposited: 04 Jul 2022 20:51
Last modified: 04 Jul 2022 20:51
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Author:
Daniel Ballestro
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