Global Change Scientists Use New Technology to Predict Intensity of Hurricanes

Posted: September 19, 2006 at 1:00 am, Last Updated: November 30, -0001 at 12:00 am

By Tara Laskowski

Researchers at the Center for Earth Observing and Space Research (CEOSR) used satellite microwave technology and buoy measurements – predictive tools that had until now not been used in this way – to successfully predict that the recent tropical storm Ernesto could not develop into hurricane strength.

Although it is well known that high sea temperature is linked to hurricane intensity changes, most past research based on satellite measurements used infrared technology that does not penetrate clouds. It was therefore difficult to find a direct relationship between hurricanes and sea temperature because of the extremely cloudy conditions present during severe weather events.

“Our approach is based on what we call a sensor web, a combination of satellite and ground measurements that allow us to study changes in the sea and in the atmosphere associated with hurricanes,” says Guido Cervone, assistant professor in the Department of Earth Systems and Geoinformation Sciences.

Using the Microwave Imager (TMI) instrument on the Tropical Rainfall Measuring Mission (TRMM) spacecraft, which is a joint mission between NASA and the Japanese space agency NASDA, Mason researchers have been able to see through the clouds and find a direct relationship between warm waters and hurricane intensification. They have also used the new CEOSR satellite antenna receiving station to monitor the evolution of storms in real time.

Details of their research appeared in a recent issue of the journal Geophysical Research Letters, a top scholarly publication in the field.

The team has found that a tropical depression may need two or more days over warm waters to accumulate enough energy for further intensification into a hurricane.

“Monitoring peaks of sea temperatures during hurricane season could provide early information on an impending tropical cyclone development,” says Menas Kafatos, director of CEOSR.

Computer model simulations show that rise in sea surface temperature is directly responsible for the increases of the surface latent heat flux – the amount of energy evaporated from the surface of the ocean – that fuels hurricane intensification.

Moreover, the location of warm water anomaly may also be a very important factor for hurricane intensification. Mason researchers found that high sea surface temperature anomaly relative to the multi-year average occurred at the right side of the storm track.

This may explain why not all tropical cyclones attain peak intensity (category 5) during their life cycle and partially explain why hurricanes usually do not reach the maximum theoretical intensity when it is calculated using the magnitude of seawater only. These findings lead the team to argue that the location of the anomaly is as important as its magnitude.

“Because of the asymmetric structure associated with hurricanes, most intense clouds, precipitation and winds occur to the right side of their path, especially during the intensification stages. Understanding the role of the location of sea anomalies can help determine with greater accuracy if future storms will intensify to hurricane strength,” says Donglian Sun, research scientist in CEOSR and lead scientist in this research.

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