- 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°C less than that of the surroundings.
Which of the statements given above is/are correct?
(a) 1 only
(b) 2 and 3 only
(c) 2 only
(d) 1 and 3 only
Answer: (c)
Statement 1 is not correct: Jet streams occur both in the Northern Hemisphere as well as in the Southern Hemisphere. The actual appearance of jet streams results from the complex interaction between many variables – such as the location of high- and low-pressure systems, warm and cold air, and seasonal changes.
Statement 2 is correct: The hurricane’s centre is a relatively calm and clear area of sinking air and light winds that usually do not exceed 15 mph (24 km/h) and is typically 20-40 miles (32-64 km) across. An eye will usually develop when the maximum sustained wind speeds go above 74 mph (119 km/h) and is the calmest part of the storm. Hence, only some cyclones develop an eye.
Statement 3 is not correct: The eye is the region of lowest surface pressure and warmest temperatures. The eye temperature may be 10°C warmer or more at an altitude of 12 km than the surrounding environment, but only 0-2°C warmer at the surface in the tropical cyclone.
