APPLICATION OF SATELLITE ALTIMETRY TO OCEAN CIRCULATION STUDIES - 1987-1994

The ocean plays a key role in determining the global climate and its time evolution. To understand this role and subsequently develop techniques for predicting future climate, one must understand the dynamics of the global ocean circulation—the movement of water that transports mass, heat, salt, and other biogeochemical properties of the ocean that are closely linked to the processes of climate change. The only viable approach to observing the global ocean circulation with sufficient resolution and consistent sampling is the use of a satellite radar altimeter to measure the height of the sea surface—the sea level (Wunsch and Gaposchkin, 1980; Stewart, 1983; Wunsch, 1992). After removing the effects of the tides and atmospheric pressure from the observation, the deviation of the sea surface from the geoid, called the ocean dynamic topography, is readily related to the velocity of the surface geostrophic flow—a component of the surface flow on which the surface pressure force is balanced by the Coriolis force due to the Earth's rotation. Moreover, the ocean dynamic topography provides a strong constraint for determining the ocean circulation through the entire water column via the dynamic equations governing the fluid motion. Precise measurement of the shape of the global sea surface thus provides a powerful tool for studying the dynamics of the ocean circulation. Copyright 1995 by the American Geophysical Union.