Antarctic Zone Arctic Circle Arctic Zone Frigid Zones Torrid Zone Tropic of Cancer Tropic of Capricorn Variable Zones anticyclone antitrades calm climate clime dead calm deathlike calm doldrums equator flat calm latitude longitude longitude in arc lull meridian oily calm parallel polar easterlies prevailing westerlies prime meridian roaring forties subtropics the line trade wind trades tropic tropics wind-equator windlessness zone