Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.568808
Title: Bio-optical properties and its application for ocean colour algorithm in east coast of Peninsular Malaysia water
Author: Idris, Suffian B.
Awarding Body: Prifysgol Bangor University
Current Institution: Bangor University
Date of Award: 2012
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Abstract:
The core subject of this thesis is to assess the applicability of ocean colour algorithms for deriving chlorophyll and CDaM concentrations in east coast of Peninsular Malaysia waters. A series of bio-optical observations were conducted in the study area during the 2009 seasons. These included in-water constituents (chlorophyll, suspended sediment and CDaM), absorption properties and reflectance. The analysis of the data reveals a clear seasonal signal with high values of all constituents and absorption properties during the northeast monsoon and low - . values during the southwest and inter-monsoon seasons. The timing, magnitude and spatial extent of these changes are associated with seasonal changes in hydrographic conditions (wind forcinq, sea surface temperature and freshwater input). Contrary to the trend during the monsoon seasons, inter-monsoon chlorophyll concentrations were higher offshore with some evidence of the pigment packaging effect. In the blue part of the spectrum, non-phytoplankton material (CDaM and detritus) is a dominant absorber (> 70% of non-water absorption) regardless of the season and this does not always covary with chlorophyll concentration. The performance of standard empirical and semi-analytical ocean colour algorithms at retrieving chlorophyll concentration was evaluated and validated using the bio-optical data in the study area. The results of our analysis showed that both types of algorithm often perform poorly in the study area, either due to a wide range of variation in in-water constituents or uncertainties in the spectral shape and magnitude of inherent optical properties. Using a series of in-situ bio- optical data, the algorithm best-suited for the study area was developed and evaluated. The results of this study indicate that a regionally-tuned chlorophyll algorithm can provide more accurate estimate of chlorophyll concentration provided that there exist a mean relationship between chlorophyll and CDaM, and the spectral shape of absorption does not change with varying environmental conditions. The most consistent result of this study was that absorptions ii by phytoplankton and CDaM can be well estimated by a simple blue-green band ratio, offering a great opportunity to discriminate chlorophyll from CDaM. Time-series of remote sensed distributions of chlorophyll, CDaM, sea surface temperature and wind speed were examined to evaluate variability of physical forcing and environmental conditions on seasonal and inter-annual variations in ocean colour in the study region. The results of this study confirm that the strong seasonal and inter-annual cycles of chlorophyll and CDaM concentrations are related to climatically driven cycles of rnonsoon and physical forcing (wind speed and SST). It is also shown that the annual cycle for both chlorophyll and CDaM concentrations is often overshadowed by inter-annual climate variability.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.568808  DOI: Not available
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