ISBN: | 978-5-5106-0884-7 |
High Quality Content by WIKIPEDIA articles! A high-pressure area is a region where the atmospheric pressure at the surface of the planet is greater than its surrounding environment. Winds within high-pressure areas flow outward due to the higher density air near their center and friction with land. Due to the Coriolis effect, winds flow clockwise around a high-pressure area located in the northern hemisphere and counter-clockwise (BE: anticlockwise) around one in the southern hemisphere. The resulting weather system is called an anticyclone. In general, high-pressure areas are associated with cooler, drier air as well as clearing skies due to their formation within areas of atmospheric subsidence, or areas of large-scale air descent. The strongest high-pressure areas are associated with arctic air masses during the winter, which modify and weaken once they move over relatively warmer water bodies. The area of high pressure associated with the descending branch of the Hadley cell, known as the subtropical ridge, steer tropical waves and tropical cyclones across the ocean and is strongest during the summer. The subtropical ridge also helps form most of the world`s deserts. Arctic high-pressure systems weaken with height, while subtropical ridges strengthen with height. On English-language weather maps, high-pressure centers are identified by the letter H. Weather maps in other languages may use different letters or symbols.