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 10°C lesser than that of the surroundings.

Which of the statements given above is/are correct?

The correct option is 2 only.

Let us analyze each statement step-by-step to understand why only the second statement is correct:

Statement 1: Jet streams occur in the Northern Hemisphere only.
This statement is incorrect. Jet streams are strong, narrow bands of wind in the upper atmosphere that blow from west to east. They are formed by the temperature differences between polar and tropical air masses combined with the Earth's rotation (Coriolis effect). Because these temperature gradients and rotation exist in both halves of the globe, jet streams occur in both the Northern Hemisphere and the Southern Hemisphere.

Statement 2: Only some cyclones develop an eye.
This statement is correct. The "eye" is a characteristic feature of strong, mature tropical cyclones (such as hurricanes or typhoons). Temperate (extra-tropical) cyclones do not have a well-defined eye. Furthermore, even among tropical cyclones, weaker or developing systems do not exhibit this clear, low-pressure, calm center known as the eye. Therefore, only some cyclones develop an eye.

Statement 3: The temperature inside the eye of a cyclone is nearly 10°C lesser than that of the surroundings.
This statement is incorrect. The eye of a tropical cyclone is a region of sinking air (subsidence). As the air descends, it compresses and warms adiabatically. Consequently, the temperature inside the eye is actually warmer, not cooler, than the surrounding cloud regions. The temperature inside the eye is typically higher than that of the surroundings at the same altitude.

Since only Statement 2 is correct, the correct choice is 2 only.