Cyclone’s Effect on Monsoon Onset, Mawar, Biparjoy, and Guchol Cyclones

Cyclone’s Effect on Monsoon Onset in News

Global warming has noticeable effects on various aspects of monsoons, including their start, end, overall rainfall patterns, and the occurrence of extreme events. Furthermore, global warming influences the behavior of cyclones in the Indian Ocean and typhoons in the northwestern Pacific Ocean.

Cyclone’s Effect on Monsoon Onset

The occurrence of cyclones during the pre-monsoon cyclone season has been observed to happen closer to the onset of the monsoon. This phenomenon can be attributed to the influence of a warmer Arctic Ocean on the winds over the Arabian Sea.

• The monsoon season is not only influenced by the Indian, Atlantic, and Pacific tropical oceans but also by the “atmospheric bridge” originating from the Arctic and the “oceanic tunnel” connecting distant regions within the ocean.
• In this context, a “bridge” signifies the interaction between two distant regions in the atmosphere, while a “tunnel” represents the connection between two remote oceanic areas.
• Fortunately, a delayed monsoon onset does not necessarily imply a deficit in monsoon rainfall. However, this year presents a unique situation with the looming El Niño phenomenon. As a result, the nation patiently waits and watches for the monsoon’s arrival, hoping for the best while also preparing for potential challenges.

Cyclone Position and Impact on Monsoon

Certain cyclones in the North Indian Ocean have shown both positive and negative effects on the initiation of the monsoon. The direction of winds circulating around these cyclones is counterclockwise, and their positioning plays a crucial role in influencing the transition of the monsoon trough.

• The monsoon trough is a region of low atmospheric pressure that is a distinctive characteristic of monsoons.
• For instance, when a cyclone is located farther north in the Bay of Bengal, the opposing winds blowing from the southwest to the northeast can exert a pulling force on the monsoon trough, aiding in the onset of the monsoon.

Example of Cyclone Mocha

During the earlier part of this year, a cyclone named Mocha formed in the Bay of Bengal in the first half of May. It briefly intensified into a “super cyclonic storm” but rapidly weakened upon making landfall.

• The unusual trajectory of Mocha, moving from northwest to east over the Bay of Bengal, was a result of atypical anticyclones (which rotate clockwise) that remained stationary over the Arabian Sea and the Bay of Bengal since March.
• Mocha eventually dissipated on May 15, and the opposing winds facilitated the timely onset of the monsoon over the Andaman and Nicobar Islands.

Cyclone Biparjoy Example

The presence of unusual anticyclones since March has led to a significant and concerning outcome. Both the Arabian Sea and the Bay of Bengal have experienced a temperature increase of over 1ºC during the pre-monsoon period.

• As a consequence, the ongoing late-season cyclone Biparjoy continues to develop in the warm waters of the Arabian Sea and there is a possibility of rapid intensification, indicated by an anticipated increase in wind speeds by 55 kmph within a span of 24 hours, before the cyclone reaches land.

Mawar, Guchol, Biparjoy and Their Interaction

Currently, Cyclone Biparjoy is not significantly influencing the monsoon trough. However, the delayed formation of the cyclone and the late onset of the monsoon season are closely linked to typhoons occurring in the northwestern Pacific Ocean.

• Typhoon Mawar formed on May 19 and ceased to exist by June 3. It attained the status of a “super typhoon” and holds the distinction of being the most intense typhoon to develop in May.
• As of now, it stands as the strongest cyclone of the year 2023.
• Meanwhile, tropical storm Guchol is presently active in the vicinity of the eastern Philippines and is expected to continue moving northwest before eventually changing direction towards the northeast.
• These formidable typhoons have a substantial thirst for moisture and draw it from distant regions.
• Mawar generated wind patterns that extended across the equator, influencing the North Indian Ocean and resulting in the establishment of southwesterly winds over certain areas of the Arabian Sea and the Bay of Bengal.

Southwesterly winds and Impact on Monsoon

“Southwesterly” refers to winds blowing from the southwest direction. The presence of southwesterly winds over the Arabian Sea is favorable as they carry substantial amounts of moisture towards the Indian subcontinent.

• However, southwesterly winds over the Bay of Bengal pose a challenge for the monsoon. In the southern regions of the Bay of Bengal, the monsoon winds initially blow in from the southwest and west directions but later change course, moving northwest towards India from the southeast.
• During the active phase of Typhoon Mawar, the winds over the entire Bay of Bengal were consistently blowing from the southwest direction.
• This pattern persists presently due to the presence of Guchol, which has now intensified into a “severe tropical storm.”
• The winds have been robustly blowing towards the northeast direction over the Bay, which has hindered the progress of the monsoon trough in reaching Kerala.

Conclusion

The intricate interplay between global warming, the formation of cyclones over the Pacific and North Indian Oceans, the warming of the North Indian Ocean, and the occurrence of late pre-monsoon cyclones and typhoons adds complexity to the dynamics of the monsoons. This complexity also challenges the accuracy of predictions regarding the monsoon’s onset and its behavior throughout the season. Previously considered a highly reliable system with its predictable northwestward migration and southeastward withdrawal, the monsoon trough now finds itself affected by the uncertainties of climate change.

Cyclone Biparjoy 2023 Live Updates on Arabian Sea Impacts and Disasters

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