A Control Theory Approach to Atmospheric-Ocean Interaction
OCCI Funded Project: 2004What are the primary questions you are trying to address with this research? (Or, if more appropriate, is there a hypothesis or theory that you are trying to prove or disprove?)
In middle latitudes, the atmosphere behaves chaotically, with weather patterns which are difficult to predict more than a few days in advance. However, it also has long-term patterns which persist for months, or even recur from year to year. Some believe these patterns are driven by sea surface temperature (SST) changes which heat or cool the atmosphere. We want to learn which patterns of heating and cooling are most effective in creating long-term changes in atmospheric circulation.
What is the significance of this research for others working in this field of inquiry and for the broader scientific community?
Most studies of atmospheric response to ocean forcing have simply applied a certain SST heating pattern to a computer model of the atmosphere, and checked to see whether the model’s response resembles real-world patterns. But the pattern of SST forcing is obtained through guesswork. We are working backwards from the known atmospheric patterns to find out which SST pattern excites them most effectively. This is a totally new approach to this longstanding problem.
What is the significance of this research for society?
If we can understand the month-to-month and year-to-year persistence of certain atmospheric patterns, then we may be able to predict them in advance. This may lead to improved long-range weather forecasts. However, it’s important to note that only moderate improvement will ever be possible, because of the chaotic, fundamentally unpredictable nature of weather.
What are the greatest challenges - physical or intellectual - to conducting this investigation?
The atmosphere is chaotic and unpredictable, but constent patterns lie buried in the chaos. To find these patterns within this sea of chaos is similar to tuning in to a weak, distant radio station, almost inaudible within the static. But the atmosphere poses an even greater challenge, because we cannot simply filter out and ignore the chaotic weather patterns: they’re not just random noise, but actually play an intimate role in creating the patterns we’re looking for.