Project Summary

The objective of this proposal is to synthesize the Joint Global Ocean Flux Study (JGOFS) CO2 survey data from the Indian Ocean into three dimensional inventory and flux estimates. The recently collected WOCE/JGOFS Indian Ocean survey data will be used to determine the current total carbon dioxide and total alkalinity inventories for the Indian Ocean. The anthropogenic CO2 component of the total inventory will be isolated using two different techniques that provide information on the anthropogenic CO2 accumulation rate in this region. The net annual air-sea CO2 flux will be quantified to resolve whether this region acts as a net sink or source of CO2 to the atmosphere. Using a mass balance approach, these quantities will be used to determine the uptake rate and primary transfer pathway(s) for anthropogenic carbon in the Indian Ocean. These goals directly address the first element of the JGOFS Synthesis and Modeling Project (SMP): global and regional carbon balances. The results of this project will also indirectly impact the other elements of the SMP by providing initialization fields to modelers running regional numerical carbon cycle studies in the Indian Ocean and the direct evaluation of global carbon models commonly used for predicting future climate change.

The ultimate goal in the interpretation of the JGOFS survey data is to generate a global picture of the current inorganic carbon distribution, including the anthropogenic component. The global compilation is beyond the scope of this proposal, however, the work proposed here will provide the foundation for future efforts. We will work with investigators examining other regions to ensure that the final data products are uniformly calibrated and that estimation techniques are fully compatible. We are also in a key position to facilitate the close interaction between the model and measurement groups necessary to synthesize these results into a set of models used for prediction (the central goal of the SMP).