The ocean occupies over 70% of the earth's surface. Because it has enormous thermal inertia and because circulations act on very long time scales, the ocean moderates changes on the atmosphere and land. These changes include relatively short-lived phenomena such as El Nino, as well as longer term changes to the global climate.
We are investigating a wide range of fundamental physical and geochemical processes in global ocean circulation and the impacts these processes have on the global climate. We are study the variability of the ocean from interannual to interdecadal time scales using the state-of-art ocean models and observational data sets. In one project, we constructed the global sea surface temperature trend of the last 50 years. The trend exhibits complex spatial structures, including warming in the tropical Pacific and cooling in the subtropical Pacific and high latitude North Atlantic, which can be interpreted in terms of various regional processes. Other work is centered on oceanic circulations in the past and in the future.
The ocean is also one of the most important carbon sinks on earth, and so strongly influences the global carbon budget. Understanding how carbon dioxide (CO2) concentration has changed in the past and will change in the future requires knowledge about the relationships between atmospheric CO2 concentration and CO2 emission from anthropogenic and natural sources. Our research in this area centers on numerical models of the carbon cycle. More information about the global carbon cycle can be found at http://carboncycle.aos.wisc.edu.