Oceans and Climate
The GFDL Oceans and Climate Group consists of scientists focused on studying the fundamental mechanisms setting the large scale climate of the World Oceans. For this purpose, we employ a hierarchy of numerical and analytical models.
The ocean provides long time scales for the earth climate system, and in so doing it impacts on the space and time scales of climate variability and change. Of particular importance for anthropogenic climate change is the ocean's role in exchanging heat and carbon with the atmosphere. A key goal of the Ocean Group is to understand the mechanisms for these exchanges, including mechanisms for the transport and mixing of heat and carbon within the ocean interior.
Numerical ocean models are the most general and powerful tools for understanding and quantifying the role of the ocean in the climate system. GFDL's efforts at ocean model development focus on the Modular Ocean Model (MOM) and the Generalized Ocean Layered Dynamics model (GOLD). MOM is the main production code used at GFDL and whose origins date back 50 years, and GOLD is a new research model which is being used to address the limitations of traditional models such as MOM. A central aim of the Ocean Group is to develop the most robust and flexible model tools available for the wide range of applications required for global ocean-climate modeling.
Ocean mesoscale eddies are the "storms" of the ocean, with typical horizontal scales less than of order 100 km, and contain more than half the kinetic energy of the ocean circulation. Such eddies affect the ocean stratification, and impact the uptake and transport of heat and carbon. The Ocean Group uses numerical models and theoretical understanding to better capture the effects of such eddies in coarse resolution models where the eddies must be parameterized, and the fine resolution models where the eddies are resolved.
Turbulent mixing between water masses occurs at scales of order 10s to 100s of meters in both the ocean interior and near boundaries, comprising a wide suite of physical processes. Such mixing processes are not resolved by ocean climate models. A central aim of the Ocean Group is to provide rational methods for the parameterization of the key mixing processes. Examples of recent particular focus at GFDL include stratified shear mixing, tidally driven mixing, surface boundary layer mixing and entraining dense overflows.
The earth's climate has undergone a wide variety of fluctuations throughout the plant's history. Understanding the mechanisms underlying fluctuations, such as the ice ages, represents one of the most basic questions of earth system science. The Ocean Group studies such past natural cycles in order to provide a means to assess present climate, and to understand the potential for future climate change under increased anthropogenic forcing.