Intertropical Convergence Zone Intertropical Convergence Zone The Intertropical Convergence Zone (ITCZ), known by sailors as the doldrums or the calms, is the area encircling Earth near the Equator, where the northeast and southeast trade winds converge. The ITCZ was originally identified from the 1920s to the 1940s as the "Intertropical Front" ("ITF"), but after the recognition in the 1940s and the 1950s of the significance of wind field convergence in tropical weather production, the term "ITCZ" was then applied. When it lies near the Equator, it is called the near-equatorial trough. Where the ITCZ is drawn into and merges with a monsoonal circulation,
2013 Atlantic hurricane season advection of cold air and water. Consequently, there was a significant cooling of sea surface temperatures over portions of the north Atlantic. This resulted in a continuation of the spring weather pattern over the Atlantic Ocean, with strong vertical wind shear, reduced mid-tropospheric moisture, and high atmospheric stability. The weak THC also resulted in slightly stronger trade winds and less wind convergence and rainfall in the Intertropical Convergence Zone, with an increase in upper-level zonal winds and higher environmental air pressures. Collectively, these factors worked to suppress tropical cyclogenesis. Tropical cyclogenesis began in early June, with the development of Tropical