Although Chennai and Mangalore are located near the same latitude, their rainfall distribution varies significantly due to differences in coastal orientation, topography, and the influence of seasonal monsoons. Mangalore experiences heavy rainfall during the Southwest Monsoon, while Chennai receives most of its precipitation during the Northeast Monsoon. This variation is largely a result of the direction of prevailing winds and geographic features influencing atmospheric behavior.
Reasons for Rainfall Differences:
- Mangalore lies on the west coast and is directly exposed to moist winds from the Arabian Sea.
- These winds ascend over the Western Ghats, causing orographic rainfall during the Southwest Monsoon (June–September).
- Chennai, located on the east coast, lies in the rain shadow region, and the Southwest Monsoon winds pass parallel to the coast, yielding less rainfall.
- The city receives most of its rainfall from the Northeast Monsoon (October–December), influenced by cyclonic systems over the Bay of Bengal.
Moving to a global perspective, recent climatic studies have highlighted the emerging influence of the Arctic Sea on India’s monsoon system. Rapid melting of Arctic ice is altering upper atmospheric patterns and influencing seasonal behavior in South Asia.
Role of Arctic Sea in India’s Monsoon System:
- Declining Arctic sea ice affects global heat distribution, shifting jet streams and upper-level wind patterns.
- These changes impact the Indian Summer Monsoon Rainfall (ISMR), leading to increased variability.
- Regions like central and northern India may receive excess rainfall, while peninsular areas might experience deficits.
- The phenomenon contributes to delayed onset, uneven distribution, and extreme weather events across India.
In conclusion, while regional geography explains local differences in rainfall, Arctic climate shifts represent a growing concern for the stability and predictability of India’s monsoon, demanding stronger climate models and adaptive strategies in policy planning.