Question 8 from UPSC CSE 2020 - GEOGRAPHY

Question

Consider the following statements:
1. Jet streams occur in the Northern Hemisphere only.
2. Only some cyclones develop an eye.
3. The temperature inside the eye of a cyclone is nearly 10Â°C lesser than that of the surroundings.
Which of the statements given above is/are correct?

IASCODEX · Accepted Answer

Correct Option: C. 2 only

Strategy: Evaluate each statement regarding meteorological phenomena:

*   **Statement 1:** Incorrect. Jet streams are a global atmospheric phenomenon found in both hemispheres.
*   **Statement 2:** Correct. Not all cyclones, but specifically intense ones like mature tropical cyclones and hurricanes, develop a clear, defined eye.
*   **Statement 3:** Incorrect. The eye of a cyclone is typically warmer, not colder, relative to its surrounding environment at upper levels; a 10°C lower temperature is inconsistent with meteorological understanding.

Thus, only Statement 2 is correct.

Key Info: ## Jet Streams
Jet streams are narrow bands of fast-flowing air currents located at altitudes near the tropopause (approximately 9-16 km) in both the Northern and Southern Hemispheres. They typically form between the boundaries of warm and cold air masses and are strongest during winter. The most prominent types are the Polar and Subtropical jet streams.

## Cyclones and the Eye
Cyclones are rotating wind systems that develop over warm ocean waters. A mature tropical cyclone (e.g., hurricane or typhoon) may develop a central 'eye.' This eye is a region of generally calm weather and low atmospheric pressure, encircled by the eyewall, which consists of intense thunderstorms. The presence of an eye indicates a well-developed and intense storm. Not all cyclones possess an eye; it only forms when the storm reaches sufficient intensity, typically with winds exceeding 119 km/h.

## Eye Temperature
The temperature within the eye of a mature tropical cyclone is characteristically warmer than the surrounding storm, particularly in the middle and upper troposphere. This temperature difference can be as significant as 10°C at higher altitudes. At the surface, however, the temperature difference is usually less pronounced, typically 0-2°C warmer than the storm's surroundings. The eye's temperature profile is a key indicator of the storm's strength and organization.

IASCODEX · Answer

Option A: 1 only

IASCODEX · Answer

Option B: 2 and 3 only

IASCODEX · Answer

Option D: 1 and 3 only

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 10Â°C lesser than that of the surroundings. Which of the statements given above is/are correct?

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 10Â°C lesser than that of the surroundings.
Which of the statements given above is/are correct?