Hurricane Simon appeared to be keeping a secret before it rapidly intensified on Oct. 4, but the Global Precipitation Measurement or GPM satellite was able uncover it.
On Oct. 4 at 0940 UTC (5:40 a.m. EDT) observations by the Ku-band radar on the GPM satellite suggested that the Eastern Pacific Ocean's Hurricane Simon was hiding a very compact eyewall hours before the National Hurricane Center detected rapid intensification of Simon's surface winds. The GPM satellite was launched in February of this year and is managed by both NASA and the Japan Aerospace Exploration Agency.
"This eyewall, a hollow ring of intense storms, had a diameter too small to be detected by other satellite instruments or with real time wind analyses that blend together such satellite observations," said Owen Kelley of NASA's Goddard Space Flight Center in Greenbelt, Maryland.
Kelley analyzed the GPM data. "The intense convective cells (small, intense, short-lived rainstorms) that sometimes occur in compact eyewalls are known to be able to cause rapid intensification of hurricanes, but such small features are only easy to detect with radar." That basically means radar-equipped aircraft or the GPM satellite must fly over the storm.
The NOAA P-3 aircraft did fly through Hurricane Simon on Oct. 4, but only after the National Hurricane Center determined that rapid intensification had already occurred.
In the coming years, GPM will enable scientists to study such unusual meteorological situations and may improve our understanding of hurricanes and of other kinds of severe storms. The GPM satellite will collect observations from a vast, but intermittent, sample of interesting meteorological situations, such as Hurricane Simon.
The GPM satellite will collect observations from the Arctic to the Antarctic circles and everything in between over the next three years, and perhaps longer. GPM will see features of the world's weather that otherwise might remain undetected.
At 5 a.m. EDT (2 a.m. PDT) on Oct. 4 the National Hurricane Center reported that Hurricane Simon was unable to form an eyewall that completely circled the eye because of a gap on the northeast side. Operational wind analyses that may have guided this statement were done at 11 p.m. on Oct. 3 and 3 a.m. PDT on Oct. 4. Those analyses showed a radius of maximum wind that was moderately large, 47 to 52 km (29 to 43 miles).
At 2:40 a.m. PDT, the GPM satellite saw that Hurricane Simon had a very compact eyewall. The eyewall had a radius of merely 10 km (6.2 miles) and hid a powerful convective cell. "The convective rain cell contained a 45 dBZ radar-reflectivity signal that reached 6.4 km (3.9 miles) altitude which is unusually high for such a strong signal in a hurricane eyewall," Kelley said.
Compact eyewalls can increase the chance of rapid intensification because there is so little air trapped in the eye of the hurricane. The small volume of air in a small eye is easier to heat with the energy released when rain forms in the eyewall. Ultimately, this energy lowers the surface air pressure under the eye, and in response, the circling winds speed up at the ocean's surface.
At 8 a.m. PDT, the National Hurricane Center reported that rapid intensification had occurred and that a small eye was visible. At 10:20 a.m. PDT the NOAA P-3 aircraft flew through Hurricane Simon and reported that the maximum winds were 10 km away from the center of the eye, which suggests that the very compact eyewall that GPM had observed at 2:40 a.m. had persisted and may have been Hurricane Simon's primary eyewall (the region of maximum wind speed) throughout this period.
This aircraft overflight was the first time that the NOAA P-3 had flown through Hurricane Simon, making the GPM overflight earlier that day the only prior radar "fix" on Hurricane Simon's "heat engine," its eyewall and eye. A detailed analysis would be needed to figure out how all of these observations illuminate Hurricane Simon's rapid intensification.
GPM data courtesy of NASA and JAXA.
For more information, visit: www.nasa.gov/gpm
Rob Gutro | Eurek Alert!
Global study of world's beaches shows threat to protected areas
19.07.2018 | NASA/Goddard Space Flight Center
NSF-supported researchers to present new results on hurricanes and other extreme events
19.07.2018 | National Science Foundation
A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
20.07.2018 | Power and Electrical Engineering
20.07.2018 | Information Technology
20.07.2018 | Materials Sciences