Fujiwhara Effect


    In News

    • Recently, two cyclones, namely super typhoon Hinnamnor & tropical storm Gardo started hovering around the central line between them, showcasing the Fujiwhara Effect. 

    About the Fujiwhara Effect

    • Definition:
      • The Fujiwhara Effect is any interaction between tropical storms formed around the same time in the same ocean region with their centers or eyes at a distance of less than 1,400 km, with intensity that could vary between a depression (wind speed under 63 km per hour) and a super typhoon (wind speed over 209 km per hour).
    • Propounder:
      • The Fujiwhara effect was identified by Sakuhei Fujiwhara, a Japanese meteorologist whose first paper recognising the Fujiwhara cases was published in 1921. 
    • Known examples:
      • The first known instance of the effect was in 1964 in the western Pacific Ocean when typhoons Marie and Kathy merged.
    • What it may lead to:
      • The interaction could lead to changes in the track and intensity of either or both storm systems
      • In rare cases, the two systems could merge, especially when they are of similar size and intensity, to form a bigger storm.
    • There are five different ways in which the Fujiwhara Effect can take place. 
      • The first is elastic interaction: 
        • In this only the direction of motion of the storms changes and is the most common case. 
        • These are also the cases that are difficult to assess and need closer examination.
      • The second is partial straining: 
        • In this a part of the smaller storm is lost to the atmosphere.
      • The third is complete straining out: 
        • In this the smaller storm is completely lost to the atmosphere. The straining out does not happen for storms of equal strength.
      • The fourth type is partial merger: 
        • In this the smaller storm merges into the bigger one and 
      • The fifth is complete merger: 
        • It takes place between two storms of similar strength.
      • During a merger interaction between two tropical cyclones the wind circulations come together and form a sort of whirlpool of winds in the atmosphere.

    Source: DTE