The hurricane model will then assimilate the data–wind conditions, temperature, pressure, humidity, and other oceanic and atmospheric factors in and around the storm–and analyze it using mathematics and physics to create a model, explains Surgi. To understand hurricane problems in the tropics, it is imperative to understand the physics of the air-sea interface. “In the last several years, we have learned a lot about the transfer of energy between the upper part of the ocean and the lowest layers of the atmosphere,” she says. “And the energy fluxes across that boundary are tremendously important in terms of being able to forecast a hurricane’s structure.”
Improving the intensity forecast of a storm and being able to precisely analyze a hurricane’s structure were scientists’ main goals in developing the new model. It can now forecast these aspects from 24 hours out up to five days out with extreme accuracy, says Ginis. The new model was put to the test by running three full hurricane seasons–2004, 2005, and 2006–for storms in both the Atlantic and east Pacific basin, totaling close to 1,800 tests runs. For example, the model was able to reproduce the life cycle of Hurricane Katrina very well, accurately forecasting that it would become a category 5 hurricane over the Gulf of Mexico–something the old model was unable to predict.
Over the next several years, scientists at NOAA will continue to improve upon these initial advancements with further use of ocean observations. They plan to couple the HWRF with a wave model, which will allow scientists to better forecast storm surge, inland flooding, and rainfall. NOAA has, in addition to partnering with URI in 2006, started collaborating with researchers at the University of Southern Alabama to work on coupling the HWRF with a wave model and enhancing its forecasting features.
“This model is enormously important for emergency response and emergency managers, and also the public,” says Ginis, “because we not only want to know where the storm is going to make landfall, but also how powerful it is going to be.”