Consider the following statements :

Jet streams occur in the Northern Hemisphere only

Only some cyclones develop an eye

The temperature inside the eye of a cyclone is nearly 10℃ lesser than that of the surroundings

Which of the statements given above is/are correct?

Question

Consider the following statements :

Jet streams occur in the Northern Hemisphere only
Only some cyclones develop an eye
The temperature inside the eye of a cyclone is nearly 10℃ lesser than that of the surroundings

Which of the statements given above is/are correct?

Accepted Answer

2 only Quick Verdict: Statement 2 is correct because only mature, high-intensity tropical cyclones develop a recognizable "eye." Statement 1 is incorrect because jet streams exist in both hemispheres. Statement 3 is incorrect because the eye is actually the warmest part of the storm, not the coldest. Thematic Discussion: Tropical Cyclones and the "Eye" Formation of the Eye (Statement 2 - Correct): Not all cyclones develop an eye. An "eye" is a cloud-free, relatively calm region at the centre of a storm. It only forms in highly organized, mature tropical cyclones when wind speeds reach at least 119 km/h (hurricane/typhoon strength). Weaker tropical depressions or extratropical cyclones do not have an eye. Temperature of the Eye (Statement 3 - Incorrect): Of all the segments of a tropical cyclone, the eye has the lowest barometric pressure and the highest While the outer eyewall features intense updrafts of moist air, the air inside the central eye is actually sinking (subsiding). As this air sinks, it compresses and warms adiabatically, making the inside of the eye up to 10°C warmer than the surrounding storm clouds at higher altitudes. 📝 Mains Practice Question (GS Paper 1 - Physical Geography): Discuss the structural characteristics of a mature tropical cyclone. Explain the atmospheric mechanisms that lead to the formation of a calm, warm "eye" surrounded by a violent eyewall. (150 words, 10 marks) Thematic Discussion: The Global Jet Streams Statement 1 - Incorrect: Jet streams are strong, narrow bands of high-speed westerly winds in the upper troposphere (7.5 - 14 km high). They are absolutely not confined to the Northern Hemisphere; both the Northern and Southern Hemispheres have a Polar Jet Stream and a Subtropical Jet Stream. Historical Context: Why are they called "Jet" Streams? They are primarily geostrophic winds, meaning they blow parallel to the isobars. At high altitudes in the upper troposphere, the wind’s friction with the Earth’s surface is virtually zero. Because friction is so low, the Coriolis (deflection) force becomes highly effective and perfectly balances the horizontal pressure gradient force, generating a high-speed geostrophic wind. They earned the name "jet streams" during World War II when American bomber pilots flying toward Japan encountered invisible walls of headwind that drastically reduced their speed, while their return flights (west to east) were massively boosted by these concentrated rivers of high-altitude air.