Introduction
Although Chennai and Mangalore lie approximately on the same latitude, they receive rainfall in different seasons. This variation is due to differences in monsoon mechanisms, relief features, and wind direction. In recent times, global climatic factors like the Arctic Sea have also begun to influence the Indian monsoon system.
Body
Mangalore, located on the western coast, receives heavy rainfall during the Southwest Monsoon (June–September). Moisture-laden winds from the Arabian Sea strike the Western Ghats, causing orographic rainfall. Hence, rainfall is intense and concentrated in the summer months.
In contrast, Chennai, situated on the eastern coast, lies in the rain-shadow region of the Southwest Monsoon. It receives limited rainfall during this period. Its main rainfall occurs during the Northeast Monsoon (October–December), when winds pick up moisture from the Bay of Bengal and cause rainfall along the Coromandel Coast.
Regarding the Arctic Sea, shrinking Arctic sea ice due to global warming alters atmospheric circulation patterns. Arctic warming weakens the polar jet stream, which can influence the mid-latitude westerlies and indirectly affect the strength and timing of the Indian monsoon. Studies suggest a possible link between Arctic warming and erratic monsoon behavior, including prolonged breaks and extreme rainfall events.
Conclusion
Thus, despite similar latitude, monsoon wind direction and relief explain rainfall differences between Chennai and Mangalore. Emerging climatic drivers like the Arctic Sea are increasingly shaping India’s monsoon variability, highlighting the need for integrated climate-sensitive planning.
