Comparison of ATOC heat content estimates with combined estimates from a general circulation model and TOPEX/POSEIDON altimetry

Abstract

To study the role of the oceans in climate, weather, and other ocean–atmosphere phenomena, one needs to observe a global-scale turbulent fluid that is opaque to electromagnetic radiation. Acoustic tomography and satellite altimetry provide complementary observational technologies for this purpose: Tomography provides path-averaged heat content estimates with a degree of vertical resolution commensurate with the number of resolved acoustic rays or modes; altimetry provides depth-integrated heat content estimates with good horizontal coverage but with additional contributions from the wind-driven circulation and from uncertainties in the mass and salt budgets. These data, in combination with the dynamical descriptions embodied in general circulation models, are powerful tools for monitoring large-scale oceanic variability. As a first step toward the demonstration of a complete system, heat content estimates obtained by the acoustic thermometry of ocean climate (ATOC) project are compared with those obtained by constraining the MIT ocean circulation model with TOPEX/POSEIDON altimeter data. This work extends a technique that has already been successfully deployed to make basin scale state estimates in the Western Mediterranean. [Work supported by the Strategic Environmental Research and Development Program through ARPA.]