University of Maryland (UMD) scientists have carried out a novel statistical analysis to determine for the first time a global picture of how the ocean helps predict the low-level atmosphere and vice versa. They observed ubiquitous influence of the ocean on the atmosphere in the extratropics, which has been difficult to demonstrate with dynamic models of atmospheric and oceanic circulation. The results are published today in the Journal of Climate, “Local atmosphere–ocean predictability: dynamical origins, lead times, and seasonality.”
The research draws on a classic statement often heard in introductory statistics classes that “correlation is not causation.” Clive Granger was a Nobel-laureate mathematician who came up with a novel method to address this issue by distinguishing correlation from causation.
“The Granger method relies upon a simple but important notion that a cause precedes its effect, and should improve the prediction of reffect in the future. We realized that this could be a powerful method to study the interactions between atmosphere and ocean, and to provide a global picture of how well they predict each other,” said applied mathematician Safa Motesharrei, an Environmental Systems Scientist at UMD. “This method sheds light on both the potential to better predict regional climate as well as the nature of the interactions.”
“There are many physical processes that govern the interaction between the atmosphere and ocean,” said lead author Eviatar Bach, PhD student in the Department of Atmospheric and Oceanic Science (AOSC) at UMD. “For example, wind blowing on the ocean surface creates currents, and the sea surface heats up the lower atmosphere. These interactions between the atmosphere and ocean play a major role in climate and our ability to predict it, so understanding their geographical structure is important.”
Read more at University of Maryland
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