Starting August 15, NASA will begin a six-week study to better understand how hurricanes form and intensify, information that should allow for better hurricane prediction.
Weather experts are pretty good at tracking a storm and determining where it will go. But predicting whether it will whip itself into a tempest, or peter out into a gentle rain, is another matter.
The study, which is known by the acronym GRIP, which stands for Generation and Rapid Intensification Processes experiment, is the first major U.S.-based study of hurricanes since 2001.
“The potential scientific impact of this mission is enormous,” said Ramesh Kakar, the GRIP project manager at NASA. “We can hardly contain our excitement.”
The study will use three planes to observe Atlantic storms and hurricanes. The planes will provide much better data than satellites can because they can observe and measure much more precisely, with better resolution, though satellite data will be used also, Kakar explained.
Two of the planes are conventional, manned, research planes, a DC-8 and a WB-57. But the third is an unmanned drone recently acquired from the Air Force. Called the Global Hawk, the plane has been used for observation in Afghanistan and Iraq. And, it is the Global Hawk that is critical to the mission. The $35-million plane is able to fly for 30 hours. Since it will be flying out of Edwards Air Force Base in Southern California, that means it will be able to get to the Caribbean or western Atlantic and fly around and over storms for possibly a continuous 18-20 hours, NASA said.
That is longer than any observation has been able to accumulate before, and it will allow observations at a number of critical times. The plane, which flies at 60,000 feet, is “a game changer,” Kakar said.
Previously, planes have been able to fly over hurricanes for only about 2 hours.
The DC-8 will be based out of Fort Lauderdale, Fla., and the WB-57 will be based out of the NASA Johnson Space Center’s Ellington Field in Houston. Where the Global Hawk will mostly measure conditions inside the storms, the other two planes will measure conditions around the storms.
Each of the planes will carry about 15 scientific instruments. Those instruments range from dropsondes, which are small cylinders dropped through the storms that measure temperature and precipitation, to microwave detectors that can measure ocean surface wind speed and rain rate. The scientists are going to measure everything from wind speed, in three dimensions at once, to the size of drops of precipitation.
The research should address two pressing questions about hurricane formation and intensification, said Edward Zipser, a professor of meteorology at the University of Utah, who is collaborating with the mission.
One question is whether Saharan winds affect hurricane formation. In 2006, scientists predicted an active hurricane year. But that did not happen. Instead, there were just four tropical storms and five hurricanes recorded in the Atlantic during the 2006 season. That compared with 12 tropical storms and 15 hurricanes in 2005. It was noted that, earlier, in June and July, a number of large dust storms had occurred in the Sahara desert, and the dust traveled over the Atlantic, blocking the sun and cooling the ocean. Warm water is necessary for hurricane formation.
The second question is whether thunderstorm activity near the eye wall of a hurricane indicates it will intensify or calm. Most hurricanes do not have lightning and thunder because lightning and thunder require strong vertical winds, which hurricanes typically do not have. However, in 2005, Hurricane Emily was observed to have very active thunderstorms, located along the eye wall. Hurricane Emily, which devastated the Yucatan, was a very strong hurricane. So, since that time, scientists have wondered whether lightning is associated with hurricane intensity.
James Elsner, a professor at Florida State University, in Tallahassee, said there is a huge need for the information the mission might generate. He said that, despite the fact that hurricanes are a regular occurance, there is very little known about them, and he cited as an example the fact that no one really has any idea how or why hurricanes form.
Elsner said that when storms form way out to sea they can be tracked and people can be warned with ample time. However, some hurricanes form from storms close to the coast, when people have little time to prepare and protect their property. In those cases, it would be hugely beneficial to predict.
“We do get storms that occur very close to the coast line and with those storms it is really important to be able to predict which ones will become hurricanes and which ones will not,” he said.
NASA expects to spend about $4 million on the study this year, said Stephen Cole, an agency spokesperson.