Asymmetry of the Intertropical Convergence Zone Asymmetry of the Intertropical Convergence Zone There are a number of explanations of the asymmetry of the Intertropical Convergence Zone (ITCZ), known by sailors as The Doldrums. The ITCZ would be expected to overlie the geographic equator according to symmetric solar radiation. However, the ITCZ is mostly perennial in the northern hemisphere and in the eastern Pacific and Atlantic Oceans. It was originally explained by the asymmetrical distribution of continents. However, the distribution of land and ocean is severely asymmetric in the Indian Ocean, yet the ITCZ moves back and forth there between the southern and northern hemispheres. Continents surround
Puget Sound Convergence Zone de Fuca meeting northerly air moving southward down the Strait of Georgia. Puget Sound Convergence Zones, variable in both location and strength, tend to form in the general vicinity of central and southern Snohomish and northern King counties in Washington, from Everett to the Northgate neighborhood of Seattle. The strongest part of the Convergence Zone (where the heaviest precipitation falls) tends to lie along and adjacent to the King-Snohomish County line so that neither county is left dry. The proximity of the Convergence Zone to the King-Snohomish County line is the reason that cities located just north or south of