Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Hurricanes at the Equator: "Impossible Perfect Storm" Observed

13.05.2003


Hurricanes cannot form near the equator, or so meteorology textbooks maintain. But a storm named Typhoon Vamei upended scientists’ thinking when it swirled above the equator in the South China Sea near Singapore on December 27, 2001. It formed so close to the equator that its winds howled in both hemispheres.


The Modis satellite image shows Typhoon Vamei at 1.5 degrees North near Singapore on December 27, 2001, with circulation on both sides of the equator. The land areas are the Malay Peninsula and Sumatra to the west of the typhoon, and Borneo to the east.
Satellite Image Credit: CRISP/National University of Singapore



New research funded by the National Science Foundation (NSF) and the U.S. Navy’s Office of Naval Research reveals the unusual mechanism for the birth of such a storm.

Intense thunderstorms over expanses of warm ocean water roil the atmosphere. Earth’s rotation spins these storms through the Coriolis Effect, a deflection that results in storms whirling counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere.


The quiescent region for this force (much like the "eye" of a hurricane) is at the equator, so researchers once believed nascent storms in this region could not build the power to start spinning. Before Typhoon Vamei (hurricanes are called typhoons when they form over the Pacific Ocean), no hurricane in recorded history had formed within 200 miles of the equator.

"Typhoon Vamei happened because of two interacting systems, a weak circulation that formed over Borneo and drifted into the southern tip of the South China Sea and remained there, and a strong and persistent northeast wind surge that turned as it crossed the equator and created a large background rotation," explained NSF-awardee C.P. Chang, a meteorologist at the Naval Postgraduate School in Monterey, Calif. Chang collaborated with meteorologists C.H. Liu from the Chinese Culture University and H.C. Kuo from the National Taiwan University, both sponsored by Taiwan’s National Science Council.

"The mechanism we identified raises additional questions," remarked Chang. "Both the wind surge and the Borneo thunderstorms are common features of the winter monsoon. Why was an equatorial cyclone not observed before?"

From analyses of weather model and satellite data, the researchers found that the land-sea terrain in the equatorial South China Sea, while necessary for strengthening and turning the cross-equatorial wind surge, also places a time constraint on the confluence of events that occurred in December of 2001. Nonetheless, Vamei still wreaked havoc: U.S. Navy ships were damaged by the typhoon, and the southern Malay Peninsula was flooded by storm surges from its 87-mile-per-hour winds.

"When something like this happens—intense background winds wrapping around a weak disturbance that lingers over warm ocean waters—and that vortex starts to spin with no help from Earth’s rotation, unlikely factors have come together," said Chang. "What you have then is just about ’the perfect storm.’ The probability of a similar equatorial development is estimated to be once every 100 to 400 years, and it probably cannot happen outside the southern South China Sea."


NSF Science Expert: Pam Stephens, pstephen@nsf.gov
NSF Principal Investigator: C. P. Chang, cpchang@nps.navy.mil

Cheryl Dybas | NSF
Further information:
http://www.nsf.gov/od/lpa/news/03/tip030512.htm

More articles from Earth Sciences:

nachricht New Technique for Finding Weakness in Earth’s Crust
30.09.2016 | University of Adelaide

nachricht Researcher creates a controlled rogue wave in realistic oceanic conditions
30.09.2016 | Aalto University

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First-Ever 3D Printed Excavator Project Advances Large-Scale Additive Manufacturing R&D

Heavy construction machinery is the focus of Oak Ridge National Laboratory’s latest advance in additive manufacturing research. With industry partners and university students, ORNL researchers are designing and producing the world’s first 3D printed excavator, a prototype that will leverage large-scale AM technologies and explore the feasibility of printing with metal alloys.

Increasing the size and speed of metal-based 3D printing techniques, using low-cost alloys like steel and aluminum, could create new industrial applications...

Im Focus: New welding process joins dissimilar sheets better

Friction stir welding is a still-young and thus often unfamiliar pressure welding process for joining flat components and semi-finished components made of light metals.
Scientists at the University of Stuttgart have now developed two new process variants that will considerably expand the areas of application for friction stir welding.
Technologie-Lizenz-Büro (TLB) GmbH supports the University of Stuttgart in patenting and marketing its innovations.

Friction stir welding is a still-young and thus often unfamiliar pressure welding process for joining flat components and semi-finished components made of...

Im Focus: First quantum photonic circuit with electrically driven light source

Optical quantum computers can revolutionize computer technology. A team of researchers led by scientists from Münster University and KIT now succeeded in putting a quantum optical experimental set-up onto a chip. In doing so, they have met one of the requirements for making it possible to use photonic circuits for optical quantum computers.

Optical quantum computers are what people are pinning their hopes on for tomorrow’s computer technology – whether for tap-proof data encryption, ultrafast...

Im Focus: OLED microdisplays in data glasses for improved human-machine interaction

The Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP has been developing various applications for OLED microdisplays based on organic semiconductors. By integrating the capabilities of an image sensor directly into the microdisplay, eye movements can be recorded by the smart glasses and utilized for guidance and control functions, as one example. The new design will be debuted at Augmented World Expo Europe (AWE) in Berlin at Booth B25, October 18th – 19th.

“Augmented-reality” and “wearables” have become terms we encounter almost daily. Both can make daily life a little simpler and provide valuable assistance for...

Im Focus: Artificial Intelligence Helps in the Discovery of New Materials

With the help of artificial intelligence, chemists from the University of Basel in Switzerland have computed the characteristics of about two million crystals made up of four chemical elements. The researchers were able to identify 90 previously unknown thermodynamically stable crystals that can be regarded as new materials. They report on their findings in the scientific journal Physical Review Letters.

Elpasolite is a glassy, transparent, shiny and soft mineral with a cubic crystal structure. First discovered in El Paso County (Colorado, USA), it can also be...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Paper – Panacea Green Infrastructure?

30.09.2016 | Event News

HLF: From an experiment to an establishment

29.09.2016 | Event News

European Health Forum Gastein 2016 kicks off today

28.09.2016 | Event News

 
Latest News

First-Ever 3D Printed Excavator Project Advances Large-Scale Additive Manufacturing R&D

30.09.2016 | Materials Sciences

New Technique for Finding Weakness in Earth’s Crust

30.09.2016 | Earth Sciences

Cells migrate collectively by intermittent bursts of activity

30.09.2016 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>