Dataset: Coupled biological/chemical/physical model for the Arabian Sea, 2004 (U.S. JGOFS Synthesis & Modeling Phase project results)

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.