The Intertropical Convergence Zone is the result of the northeasterly trade winds and southeasterly trade winds converging in an area of high latent heat and low pressure.[3] As the two trade winds converge, the cool, dry air collects moisture from the warm ocean and rises, contributing to cloud formation and precipitation. The low pressure area that is created by the movement of the trade winds acts as a vacuum, drawing in the cooler, dry air from high pressure areas (divergence zones), creating a convection cell commonly known as the Hadley Cell.[3]
Sea surface temperature is directly related to the position of the Sun or the location of the "energy flux equator," thus the ITCZ shifts corresponding to the seasons.[3] Due to the position of the Sun, the sea surface temperature near the equator (30°S to 30°N), during an equinox, is higher than any other latitudes.[4] During the summer solstice in the Northern Hemisphere (June 21), the ITCZ is shifted north, following the position of the Sun.[5] The ITCZ is shifted farther south during the winter solstice (in the Northern Hemisphere), when the solar radiation is focused at 23.5°S.
Mesoscale
Convergence zones also occur at a smaller scale. Convergence lines form rows of showers or thunderstorms over a more local area. Sea breezescolliding can trigger development of a convergence line. The heavy rain caused in a short period of time can cause severe flooding.[6]
^Byrne, Michael P.; Pendergrass, Angeline G.; Rapp, Anita D.; Wodzicki, Kyle R. (2018). "Response of the Intertropical Convergence Zone to Climate Change: Location, Width, and Strength". Current Climate Change Reports4: 355-370. doi:10.1007/s40641-018-0110-5
^ abcdWaliser, D.E.; Jiang, X. (2015). "Tropical Meteorology and Climate: Intertropical Convergence Zone". Reference Module in Earth Systems and Environmental Sciences6(2): 121-131. doi:10.1016/B978-0-12-382225-3.00417-5
^Krishnamurti, T.N.; Stefanov, Lydia; Misra, Vasubanhu (2013). Tropical Meteorology: An Introduction. New York, New York: Springer Science & Business Media.ISBN978-1-4614-7409-8doi:10.1007/978-1-4614-7409-8
^Schneider, Tapio; Bischoff, Tobias; Haug, Gerald H. (2014). "Migrations and dynamics of the Intertropical Convergence Zone." Nature513: 45–53. doi:10.1038/nature13636