What Is the Fujiwhara Effect?

What Is the Fujiwhara Effect?

December 1, 2022 - 6:15 am

Is a super typhoon the most powerful in the world ?

Just a week after Hurricane Hinnamnor swallowed Gardo, Hurricanes Danielle and Earl formed in the North Atlantic Ocean one after the other, raising concerns about the Fujiwhara Effect. Another hurricane, named Kay, was also developing in the eastern Pacific Ocean at the same time. The Fujiwhara Effect happens when two tropical cyclones get close enough to each other to create a shared center, forcing the two storms to whip around that common central point. If one of the storms is stronger than the other, the weaker one will typically break apart as a result. If the storms are similar in strength, they can sometimes merge or just slingshot around each other and continue on their way.* The storms can occasionally combine to form a stronger storm. This physics lesson was illustrated when the nearby weaker tropical low was devoured by the then-Super Typhoon Hinnamnor.


What is the Fujiwhara Effect?

The Fujiwhara Effect is named after Sakuhei Fujiwhara, a Japanese meteorologist. From 1921 through 1923, Dr. Fujiwhara conducted tests on water "vortices." He observed that two cyclonic vortices might interact when they were close to one another. The vortices would cycle along an axis that connected their centres. Any interaction between tropical storms that developed at roughly the same time in the same ocean region and had their centres or eyes less than 1,400 km away from each other, with intensity ranging from a depression (wind speed < 63 km/h) to a super typhoon, is known as the Fujiwhara Effect (wind speed over 209 km per hour).


Different Types of the Fujiwhara Effect  

The Fujiwhara Effect might occur in one of five different ways. The most frequent type of interaction is the elastic type, in which only the storms' motion directions change. These are also the cases that need more in-depth investigation and are challenging to evaluate. A portion of the smaller storm is lost to the atmosphere in the second method, partial straining out. The smaller storm in the third fully strains out and is lost to the atmosphere. When storms are of similar strength, the straining out does not occur. The smaller storm partially combines with the larger storm in the fourth type. Fifth is complete merger which takes place between two storms of similar strength.                                                                                              

Depending on where they originate, hurricanes, cyclones, and typhoons are large wind circulations with whirling winds that occur over warm ocean waters. Heat, wind, and moisture are their sources of energy, and under the correct circumstances, they can significantly increase in size and strength. The large ones can have diameters greater than 1,000 km and winds greater than 250 km/h. There were 10 instances of the Fujiwhara Effect in the northwest Pacific Ocean between 2013 and 2017, the majority of which were weak interactions. Seven of them were super typhoons, which are tropical cyclones with winds more than 209 km/h. As the oceans get warmer and there are more stronger cyclones the possibility of the Fujiwhara Effect would increase drastically, like it already has. Cyclones become more unpredictable as a result of the Fujiwhara Effect because of their quick intensification, ability to carry more rain, and use of innovative techniques for moving over warming oceans. This is due to the fact that each interaction between the two storm systems is distinct and challenging for current climate models to simulate.


Challenges of the Fujiwhara Effect 

Longer-term evaluation of Fujiwhara Effect cases is problematic. There is no compiled dataset, thus researchers from all over the world often choose the Fujiwhara cases they find intriguing to explore. As these occurrences are uncommon and challenging to evaluate, the fundamental issue is that "there is no globally recognised technique or recording agency committed to recognise and collect the examples of the Fujiwhara Effect." The climate models that are currently being used to track tropical cyclones around the world should take the Fujiwhara Impact into account. This will increase their efficiency and help predict when and where the effect will occur. This will enable scientists to determine whether a megastorm is intensifying. As we continue to monitor the tropics, it is important to stay up to date on all tropical systems.