 |
| Titel |
Using empirical orthogonal functions derived from remote-sensing reflectance for the prediction of phytoplankton pigment concentrations |
| VerfasserIn |
A. Bracher, M. H. Taylor, B. Taylor, T. Dinter, R. Röttgers, F. Steinmetz |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1812-0784
|
| Digitales Dokument |
URL |
| Erschienen |
In: Ocean Science ; 11, no. 1 ; Nr. 11, no. 1 (2015-02-03), S.139-158 |
| Datensatznummer |
250117131
|
| Publikation (Nr.) |
 copernicus.org/os-11-139-2015.pdf |
|
|
|
|
|
| Zusammenfassung |
| The composition and abundance of algal pigments provide information on
phytoplankton community characteristics such as photoacclimation, overall
biomass and taxonomic composition. In particular, pigments play a major
role in photoprotection and in the light-driven part of photosynthesis. Most
phytoplankton pigments can be measured by high-performance liquid
chromatography (HPLC) techniques applied to filtered water samples. This
method, as well as other laboratory analyses, is time consuming and
therefore limits the number of samples that can be processed in a given
time. In order to receive information on phytoplankton pigment composition
with a higher temporal and spatial resolution, we have developed a method to
assess pigment concentrations from continuous optical measurements. The
method applies an empirical orthogonal function (EOF) analysis to remote-sensing reflectance data derived from ship-based hyperspectral underwater
radiometry and from multispectral satellite data (using the Medium Resolution Imaging Spectrometer – MERIS – Polymer
product developed by Steinmetz et al., 2011) measured in the Atlantic Ocean.
Subsequently we developed multiple linear regression models with measured
(collocated) pigment concentrations as the response variable and EOF
loadings as predictor variables. The model results show that surface
concentrations of a suite of pigments and pigment groups can be well
predicted from the ship-based reflectance measurements, even when only a
multispectral resolution is chosen (i.e., eight bands, similar to those used
by MERIS). Based on the MERIS reflectance data, concentrations of total and
monovinyl chlorophyll a and the groups of photoprotective and photosynthetic
carotenoids can be predicted with high quality. As a demonstration of the
utility of the approach, the fitted model based on satellite reflectance
data as input was applied to 1 month of MERIS Polymer data to predict the
concentration of those pigment groups for the whole eastern tropical
Atlantic area. Bootstrapping explorations of cross-validation error indicate
that the method can produce reliable predictions with relatively small data
sets (e.g., < 50 collocated values of reflectance and pigment
concentration). The method allows for the derivation of time series from
continuous reflectance data of various pigment groups at various regions,
which can be used to study variability and change of phytoplankton
composition and photophysiology. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|