उष्मावृद्धी केंद्रा संदर्भात खालील विधाने विचारात घ्या.
1. शहरी उष्णतेच्या केंद्राचा प्रभाव दिवसाच्या वेळी अधिक ठळकपणे जाणवतो.
ii. यामुळे ग्रामीण आणि शहरी भागात उष्णता विसंगती निर्माण होते.
iii. ग्रामीण-शहरी वातावरणातील तापमान श्रेणी शहराच्या मध्य भागी रात्रीच्या वेळी संवहनशील वायु परिसंचरण निर्माण करते.
iv. पृष्ठ भागाच्या पातळीवर शहरी भागातून तुलनेने थंड हवा रात्री उष्ण ग्रामीण भागाकडे जाते.

वरीलपैकी कोणते/ती विधान/ने चूकचे/ची आहे/आहेत ?

The correct answer is Option B (only i and iv).

Key Points:
• Urban Heat Island (UHI) Mechanics:
• Statement i is Incorrect: The Urban Heat Island effect is fundamentally most pronounced, prominent, and largest at night (several hours after sunset) rather than during the day, because concrete and asphalt slowly re-radiate stored heat into nocturnal calm air.
• Statement ii is Correct: UHI creates a distinct thermal anomaly/gradient between the warm urban core and cooler rural surroundings.
• Statement iii is Correct: Strong thermal differences generate an 'Urban Breeze' (convective rising of hot air at the city center creating localized low pressure and convection cells at night).
• Statement iv is Incorrect: The air flow direction is the exact opposite: relatively cooler air from the rural surface moves toward the warmer urban center (country breeze converging into city core), not from urban to rural.
• Therefore, statements i and iv are incorrect (Option 2).
• Key Takeaway: UHI is most prominent at night, and cool surface air flows from rural areas toward the warm urban center.