Which of the following is/are features of the Doldrums?

1. Weak horizontal movement of air

2. Low Pressure on ground

3. Presence around equator

Select the option from the codes given below:

Ans: (4)

Key Points

The Doldrums (Intertropical Convergence Zone - ITCZ)

1. Location:

• Situated around the equator, typically between 5°N and 5°S latitude.

• Encircles the Earth as a narrow belt, though it shifts slightly with the seasons.

2. Atmospheric and Climatic Features:

• Low Atmospheric Pressure: Caused by the convergence of warm air masses, which rise due to intense equatorial heating.

• Calm Winds: Known for little to no horizontal wind movement, making sailing difficult in pre-engine days.

• High Humidity: Warm, moist air creates humid conditions in this region.

• Frequent Thunderstorms: Rising air cools rapidly, leading to cloud formation and intense storms.

3. Trade Wind Convergence:

• The Doldrums form at the point where the northeast and southeast trade winds meet.

• This convergence causes vertical uplift, not horizontal motion, creating the calm.

4. Impact on Navigation:

• Historically problematic for sail-powered ships, which could get trapped due to the lack of wind.

• Sailors coined the term “doldrums” to describe the frustrating stillness.

5. Seasonal Behavior:

• The ITCZ migrates slightly north or south depending on the Earth's tilt and the Sun's position, affecting regional weather and rainfall patterns.