This proposal
outlines three research tasks designed
to develop, validate, and improve a biological/chemical/physical model
for the Arabian Sea. A focus of the proposed research is to understand
the Arabian-Sea carbon cycle, which requires that biological and physical
processes are properly represented. To understand a problem of this
complexity requires the development of a hierarchy of models that vary
in dynamical complexity. Our approach is to begin with a dynamically
simple system, to compare its solutions carefully with available data,
identify model deficiencies and to develop and test various hypotheses
for overcoming them. Our initial system will consist of three components:
a 5 ½-layer physical model, a 4-compartment NAHD biological model,
and a chemical model that simulates carbon and oxygen cycling. The
system has the advantage that it is computationally very efficient.
Consequently, we will be able to carry out extensive test runs, and hence
can carefully assess the influence of individual processes. Versions
of each component model have already proven successful at simulating observations
in the Arabian Sea and elsewhere, and this prior success gives us confidence
that the coupled system will also produce useful solutions. The initial
system will be gradually improved and expanded as we identify deficiencies
and modify the model to correct them. The central goal of the U.S.
JGOFS Synthesis and Modeling Project (SMP) is to synthesize observational
data into a set of models that can be used for prediction. Here,
we propose to bring together a group of scientists with the collective
expertise necessary to achieve this goal for the Arabian Sea.
Specifically, Sharon Smith contributes her knowledge of Arabian Sea biological
and chemical fields, Raleigh Hood and Don Olson contribute their expertise
in biological and chemical modeling, and Julian McCreary contributes his
modeling experience of physical processes in the region. Each Principal
Investigator thus performs an important function in the overall research
effort.
In this effort we will test fundamental hypotheses concerning the factors
that control biogeochemical fluxes in the Arabian Sea. This region was
selected to be the location of one of the four U.S. JGOFS Process Studies
because of its strong monsoonal forcing and large seasonal oscillations,
and indeed the project acquired the most complete seasonal and spatial
resolution of carbon cycling among the four Studies. These field observations,
in combination with concurrent ONR measurements, historical data and new
satellite ocean color observations, thus provide an ideal data set for
developing a coupled model that can respond realistically under a wide
range of oceanic conditions. Consequently, we expect that our results will
be readily generalizable to other regions of the world ocean.
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