Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Hurricanes at the Equator: "Impossible Perfect Storm" Observed


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,
NSF Principal Investigator: C. P. Chang,

Cheryl Dybas | NSF
Further information:

More articles from Earth Sciences:

nachricht Gas hydrate research: Advanced knowledge and new technologies
23.03.2018 | Helmholtz-Zentrum Potsdam - Deutsches GeoForschungsZentrum GFZ

nachricht New technologies and computing power to help strengthen population data
22.03.2018 | University of Southampton

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Space observation with radar to secure Germany's space infrastructure

Satellites in near-Earth orbit are at risk due to the steady increase in space debris. But their mission in the areas of telecommunications, navigation or weather forecasts is essential for society. Fraunhofer FHR therefore develops radar-based systems which allow the detection, tracking and cataloging of even the smallest particles of debris. Satellite operators who have access to our data are in a better position to plan evasive maneuvers and prevent destructive collisions. From April, 25-29 2018, Fraunhofer FHR and its partners will exhibit the complementary radar systems TIRA and GESTRA as well as the latest radar techniques for space observation across three stands at the ILA Berlin.

The "traffic situation" in space is very tense: the Earth is currently being orbited not only by countless satellites but also by a large volume of space...

Im Focus: Researchers Discover New Anti-Cancer Protein

An international team of researchers has discovered a new anti-cancer protein. The protein, called LHPP, prevents the uncontrolled proliferation of cancer cells in the liver. The researchers led by Prof. Michael N. Hall from the Biozentrum, University of Basel, report in “Nature” that LHPP can also serve as a biomarker for the diagnosis and prognosis of liver cancer.

The incidence of liver cancer, also known as hepatocellular carcinoma, is steadily increasing. In the last twenty years, the number of cases has almost doubled...

Im Focus: Researchers at Fraunhofer monitor re-entry of Chinese space station Tiangong-1

In just a few weeks from now, the Chinese space station Tiangong-1 will re-enter the Earth's atmosphere where it will to a large extent burn up. It is possible that some debris will reach the Earth's surface. Tiangong-1 is orbiting the Earth uncontrolled at a speed of approx. 29,000 km/h.Currently the prognosis relating to the time of impact currently lies within a window of several days. The scientists at Fraunhofer FHR have already been monitoring Tiangong-1 for a number of weeks with their TIRA system, one of the most powerful space observation radars in the world, with a view to supporting the German Space Situational Awareness Center and the ESA with their re-entry forecasts.

Following the loss of radio contact with Tiangong-1 in 2016 and due to the low orbital height, it is now inevitable that the Chinese space station will...

Im Focus: Alliance „OLED Licht Forum“ – Key partner for OLED lighting solutions

Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.

They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...

Im Focus: Mars' oceans formed early, possibly aided by massive volcanic eruptions

Oceans formed before Tharsis and evolved together, shaping climate history of Mars

A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

New solar solutions for sustainable buildings and cities

23.03.2018 | Event News

Virtual reality conference comes to Reutlingen

19.03.2018 | Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

Latest News

For graphite pellets, just add elbow grease

23.03.2018 | Materials Sciences

Unique communication strategy discovered in stem cell pathway controlling plant growth

23.03.2018 | Agricultural and Forestry Science

Sharpening the X-ray view of the nanocosm

23.03.2018 | Physics and Astronomy

Science & Research
Overview of more VideoLinks >>>