Sea Ice

SEA ICE IS frozen ocean water. It forms primarily in and near the polar regions, though it can grow closer to the equator as far as 40 degrees N latitude and 55 degrees S latitude. Sea ice has a strong seasonal variability. In the Northern Hemisphere, the annual maximum extent occurs in late winter (March), covering about 5,791,532 sq. mi. (15 million sq. km.) on average. It then melts during spring and summer to an annual minimum extent of about 2,702,715 sq. mi. (7 million sq. km.) in September. In the Antarctic, the annual maximum is about 7,335,941 sq. mi. (19 million sq. Ion.) during September, and the annual minimum is about 1,158,306 sq. mi. (3 million sq. km.) in February or March. Overall, roughly ...