Consider the following diagram : In the diagram given above, what does A denote?

In the standard diagram of global wind belts, the region labeled 'A' at the equator (0° latitude) denotes the Doldrums. This belt, also known as the Equatorial Low Pressure Belt or the Intertropical Convergence Zone (ITCZ), lies between 10° N and 10° S [2]. It is characterized by intense solar heating, which causes air to expand and rise through convection, resulting in extremely calm or light shifting winds [2]. Historically, sailors referred to this zone as the Doldrums because their ships would often become becalmed or stuck due to the lack of steady horizontal wind [3]. It serves as the convergence zone where the trade winds from the Northern and Southern Hemispheres meet before ascending [1]. While trade winds (Option 2) occupy the 5°–30° latitudes and westerlies (Option 3) dominate mid-latitudes, the specific equatorial calm belt is uniquely identified as the Doldrums.

Sources

1. [1] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 23: Pressure Systems and Wind System > Equatorial Low-Pressure Belt or 'Doldrums' > p. 311
2. [2] Certificate Physical and Human Geography , GC Leong (Oxford University press 3rd ed.) > Chapter 14: Climate > Pressure and Planetary Winds > p. 139
3. [3] https://oceanservice.noaa.gov/facts/doldrums.html