Phytoplankton are microscopic organisms that live in watery
environments, both salty and fresh. And there are a variety of phytoplankton,
varying from photosynthesizing bacteria (cyanobacteria), to plant-like diatoms,
to armor-plated coccolithophores (drawings not to scale). Phytoplankton
have chlorophyll to capture sunlight, and they use photosynthesis to turn it
into chemical energy. They consume carbon dioxide, and release oxygen. Due
to the functions, phytoplankton are of extreme importance in the ocean
environment and it is necessary to track their existence and monitor their
population distribution in the ocean environment.
However, because the phytoplankton are similar to other non-algae
carbon rich particles, it is difficult to measure their distribution, so
scientists focus on their photosynthetic pigment content, chlorophyll. They can
monitor and predict the abundance of the phytoplankton via determining the concentration
of ocean chlorophyll.
Blending technique, which is used to analyze sea surface temperature successfully,
can also be used in the calibration of ocean chlorophyll, but there is distortion
of the blended field as one approaches the coastal land. To solve the problem,
the penalized regression splines, a technique that could be used to model noisy
data, was introduced.
In this paper, the two techniques had been combined. And the authors
aimed to demonstrate how the principles of penalized regression could be
applied to the blending process in order to obtain better estimate of ocean
chlorophyll from the satellite data field. The term of interest in the blending
process were presented as a regression equation. And the authors penalized the
equation and validated the blended fields obtained from the various blending
methods. And the findings were discussed.
In conclusion, it was expected that a penalized model would be able to
perform better than a non penalized model in a situation where penalization was
necessary. And it is hoped that most of the analysis on primary productivity
and management in the ocean environment will be greatly affected since
chlorophyll is one of the most important components in the formation of the
ocean life cycle.
Article by Alfred Chioza and Shoji
Ohga, from Kyushu University, Fukuoka, Japan.
Full access: http://mrw.so/RrSWX
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| Image by Hannah Sue Gray, from Flickr-cc. |
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