NASA Supercomputers Advance State of the Art of Ocean Circulation Modeling
Global scale oceanic circulation modeling has been moving to a new gridding method that projects the faces of a cube onto the surface of a sphere. They found that this method covers the sphere more uniformly than a latitude-longitude grid, and that it produces more accurate results near Earth's poles. This is helping refine modeling of ocean currents which are critical to global climate models, and has the potential to significantly improve the accuracy of climate change modeling.
Researchers from NASA's Jet Propulsion Laboratory (JPL), Pasadena, Calif. and Massachusetts Institute of Technology (MIT), Cambridge, Mass are reaping huge benefits from research performed on NASA's advanced supercomputers.
Scientists believe the ocean and its interactions with the atmosphere are key to studying climate change. To better understand these interactions, they identified three important areas in climate research. They look at the 'states' of the ocean and sea-ice, which includes their temperature, salinity, current speeds, and sea-surface elevation, and study their changes at and below the surface. They also look at the 'state' of the atmosphere, which includes its temperature, humidity, and wind patterns, and study how it was affected by the changes in the ocean. These interactions between the atmosphere and ocean directly affect the weather. The scientists study the biological activity in the ocean and its responses to the changing 'state' of the ocean. These are important variables in the models, and require the most detailed treatment to be most accurately addressed.
In the past, the standard model gridding methods, using longitude and latitude, had difficulty assimilating data at the poles. To solve this problem, researchers started looking at the world in a new way, using a new cube-based method. But advanced computers and algorithms were needed to enable modeling at higher resolutions, said Hill.
These improvements have increased the accuracy of ocean data syntheses to such an extent that they are starting to resolve ocean eddies and other narrow currents, which transport heat, carbon, and other properties within the ocean.