Fujiwhara effect
The Fujiwhara effect or Fujiwara interaction, named after Sakuhei Fujiwhara, is a type of interaction between two nearby cyclonic vortices, causing them to appear to "orbit" each other.
Contents
Description
When the cyclones approach each other, their centers will begin orbiting cyclonically about a point between the two systems due to their cyclonic wind circulations. The two vortices will be attracted to each other, and eventually spiral into the center point and merge. When the two vortices are of unequal size, the larger vortex will tend to dominate the interaction, and the smaller vortex will orbit around it.
The effect is often mentioned in relation to the motion of tropical cyclones, although the final merging of the two storms is uncommon. The effect becomes pronounced in these storms when they approach within about 1,500 km (900 mi) of each other and are at tropical storm strength or stronger.
Namesake
The effect is named after Sakuhei Fujiwhara, the Japanese meteorologist who initially described it in a 1921 paper about the motion of vortices in water.[1][2]
Examples
North Atlantic
A few sets of examples can be found in the busy 1995 Atlantic hurricane season. During the height of the season, Hurricane Humberto and Hurricane Iris took part in a brief Fujiwara interaction.[3] Iris then began interacting with a third storm, Tropical Storm Karen, which orbited and later merged with the more intense Iris.
In 2004, Lisa absorbed a tropical disturbance as described in the Tropical Cyclone Report.[4]
In 2005, the remnant low of Tropical Depression Thirteen moved northward and then northeastward around a non-tropical low located to the north of the system. It briefly strengthened into Tropical Storm Lee. Thereafter, Lee weakened back to a tropical depression as it moved northeastward and northwestward around the eastern side of the non-tropical low and eventually absorbed the non-tropical low.[5]
In the same year, Alpha was absorbed by Wilma.
Northeast Pacific
In 1990, Norbert absorbed Tropical Depression Eighteen-E.[6]
In 2001, Gil absorbed Henriette but associated convection totally dissipated during the merger and did not return afterwards.[6]
In 2005, Lidia was absorbed by Max.[7]
Northwest Pacific
In September 1994, Typhoon Pat and Tropical Storm Ruth completed a full orbit around their centroid before collapsing into a single cyclone.[8]
In August 1997, Typhoon Amber absorbed Tropical Storm Cass over Eastern China, after both storms made landfall, on August 30.
In October 1997, Typhoon Ivan and Typhoon Joan were a pair of super typhoons that interacted through the Fujiwara effect. The interaction affected their motion as Ivan was steered to the west, and Joan was steered more northerly.
In October 2006, Severe Tropical Storm Wukong absorbed Tropical Storm Sonamu south of Japan.
In November 2007, Typhoon Hagibis made a recurvature in the South China Sea towards Typhoon Mitag northeast of the Philippines.
In October 2009, Typhoon Parma interacted with Typhoon Melor, affecting the movement of Parma. Parma was moving through the South China Sea but made a recurvature move to southeastward, so it made its second and third landfall over northern Luzon. In addition, due to the interaction with Melor, Parma weakened into a tropical storm by October 4. Also in November 2009, Typhoon Nida absorbed Tropical Depression 27W (Urduja) and become a powerful typhoon.
In August 2010, a Fujiwara interaction occurred between Tropical Storm Namtheun and Severe Tropical Storm Lionrock. Namtheun turned southwestward while Lionrock turned eastward. Later, Namtheun weakened into a tropical depression in the Taiwan Strait and was absorbed by Lionrock. At the mean time, Typhoon Kompasu was near Okinawa, Japan and did not take part in the Fujiwara interaction. Nevertheless, Kompasu disrupted the outflow of Namtheun and was partly responsible for the decay of Namtheun.
In July 2011, Typhoon Ma-on absorbed Tropical Storm Tokage. On September 16 of the same year, Typhoon Roke weakened a tropical depression.
Southwest Indian Ocean
In 2008, Tropical Cyclone Fame began orbiting Tropical Cyclone Gula with the stronger storm, Gula, absorbing Fame.
South Pacific Ocean
In early January 1998, the category 5 (in both Australian and SSHS scales) twins Cyclone Ron and Cyclone Susan started interacting on January 7. On January 9, Susan completely absorbed Ron.[9]
See also
References
- ↑ Script error
- ↑ "Fujiwhara effect describes a stormy waltz". USA Today. November 1, 2007. http://www.usatoday.com/weather/wfujiwha.htm. Retrieved 2008-02-21.
- ↑ TPC NHC IRIS 1995 PRELIMINARY REPORT
- ↑ NHC Tropical Cyclone Report
- ↑ NHC Tropical Cyclone Report
- ↑ 6.0 6.1 NHC Tropical Cyclone Report
- ↑ NHC Tropical Cyclone Report
- ↑ Joint Typhoon Warning Center - Typhoon Pat (PDF)
- ↑ Padgett, Gary (1998). "Monthly Global Tropical Cyclone Summary January 1998". Australian Severe Weather. http://www.australiasevereweather.com/cyclones/1998/summ9801.htm. Retrieved 2011-06-27.
External links
- Edward N. Rappaport, NOAA Hurricane Research Division - "Hurricane Iris Preliminary Report"de:Fujiwhara-Effekt
es:Efecto Fujiwhara fr:Effet Fujiwara ko:후지와라 효과 nl:Fujiwara-effect ja:藤原の効果 pt:Efeito Fujiwara tr:Fujiwhara etkisi zh:藤原效應
