Intertropical Convergence Zone

Meteorological phenomenon

The Intertropical Convergence Zone (ITCZ ITCH, or ICZ), known by sailors as the doldrums or the calms because of its monotonous windless weather, is the area where the northeast and the southeast trade winds converge. It encircles Earth near the thermal equator, though its specific position varies seasonally. When it lies near the geographic equator, it is called the near-equatorial trough.

From Wikipedia, under CC BY-SA. More on occurri.