The Meteorology, Climatology, and Geophysics Agency (BMKG) recently detected the formation of Tropical Cyclone Anggrek in the Indian Ocean, southwest of Bengkulu, alongside Cyclone Seed 99S near northern Australia on Tuesday (Jan. 16).
This Cyclone Anggrek poses a risk of heavy rain, lightning, and strong winds from Jan. 16 to 22, 2024, across several regions in Indonesia.
Dr. Emilya Nurjani, an esteemed climate and environmental expert from Universitas Gadjah Mada (UGM), elucidated that Tropical Cyclone Anggrek emerged from location 98 S on Monday (Jan. 16).
By Thursday (Jan. 18), Cyclone Anggrek had progressed to approximately 10.1 degrees south latitude and 94.2 degrees east longitude, about 1,130 km southwest of Bengkulu, moving southwestward at approximately 17 knots.
Tropical cyclones typically evolve from tropical depressions to storms and ultimately intensify into cyclones.
“Tropical cyclones are a global phenomenon that necessitates proactive mitigation efforts to mitigate their impacts,” she remarked during a discussion on Friday (Jan. 19).
Throughout the current rainy season, heightened rainfall isn’t solely attributed to tropical cyclones but also influenced by the Asian monsoon and the intertropical convergence zone, fostering convergent cloud growth in the Indonesian region around January-February.
“Intense rainfall can trigger floods and landslides, making flood and landslide mitigation our primary focus,” she stressed.
Various preventive measures can be adopted to preempt floods and landslides from heavy rainfall. One vital step involves clearing debris from drainage systems to ensure unimpeded water flow during downpours. Moreover, deepening river channels to accommodate increased rainwater volume is crucial.
Additionally, clearing infiltration wells or biopores to optimize rainwater storage is imperative. Equally essential is trimming old and tall trees to mitigate the impact of fallen trees during strong winds and issuing warnings to fishermen to avoid venturing into the sea.
Furthermore, she elaborated on cyclone formation, emphasizing the prerequisite conditions of a low-pressure center surrounded by high-pressure.
Cyclones materialize due to the Coriolis force deflecting winds and warm water vapor generated by the evaporation of warm seawater with temperatures exceeding 28 degrees Celsius. The Coriolis force induces warm water vapor to spiral and ascend along wind movement.
Dr. Nurjani said the potential cyclone formation zone is 30 degrees north and south latitude. The equatorial region remains cyclone-free with zero latitude due to a lack of Coriolis effect. The greater the Coriolis force, the higher the likelihood of cyclone occurrence in warm or hot seawater.
“Indonesian waters maintain a sea surface temperature of around 26.5 degrees Celsius, resulting in a lesser potential for cyclone formation compared to waters near Australia, the Philippines, Japan, and the western Indian Ocean of Asia,” she noted.
Tropical cyclones can precipitate various impacts, including heightened rainfall (in terms of thickness, duration, and intensity), elevated wind speeds, and surging sea waves (1.5 – 3 meters).
Areas directly affected by tropical cyclones experiencing intensified rainfall encompass the southern coastal regions of Sumatra and sections of western Java.
Similarly, regions with escalating waves include the southern and western waters of Sumatra and the southern waters of Java. As tropical cyclones veer southwestward away from Indonesia, their resultant impacts gradually subside.
Dr. Nurjani further explained that a cyclone’s lifespan typically spans 5-14 days, with diminished impact upon landfall. This attenuation arises from frictional forces with land, leading to wind weakening and reduced water vapor inland. Most tropical cyclones originate over water.
Author: Ika
Photographer: Firsto