in the southern hemisphere, the direction of surface wind movement about a tropical cyclone is outwards.
in the southern hemisphere what is the direction of surface wind movement about a tropical cyclone?
outwards
the near-surface wind field of a tropical cyclone is characterized by air rotating rapidly around a center of circulation while also flowing radially inwards. at the outer edge of the storm, air may be nearly calm; however, due to the earth's rotation, the air has non-zero absolute angular momentum. as air flows radially inward, it begins to rotate cyclonically (counter-clockwise in the northern hemisphere, and clockwise in the southern hemisphere) in order to conserve angular momentum. at an inner radius, air begins to ascend to the top of the troposphere. this radius is typically coincident with the inner radius of the eyewall, and has the strongest near-surface winds of the storm; consequently, it is known as the "radius of maximum winds". once aloft, air flows away from the storm's center, producing a shield of cirrus clouds.
tropical cyclone
tropical cyclones that occur within the southern hemisphere to the east of 90°e are officially monitored by one or more tropical cyclone warning centres. these are run by the fiji meteorological service, new zealand's metservice, indonesia's badan meteorologi, klimatologi, dan geofisika, papua new guinea's national weather service and the australian bureau of meteorology. within the region a tropical cyclone is defined as being a non-frontal low pressure system of synoptic scale that develops over warm waters, with a definite organized wind circulation and 10-minute sustained wind speeds of or greater near the centre. once this definition has been met then all of the centres name the system and start to use the australian tropical cyclone intensity scale, which measures tropical cyclones using a five category system based on 10-minute maximum sustained winds. a category 1 tropical cyclone is estimated to have 10-minute sustained wind speeds of , while a category 2 tropical cyclone is estimated to have 10-minute sustained wind speeds of . when a system becomes a category 3 tropical cyclone it is reclassified as a severe tropical cyclone and has wind speeds of . a category 4 severe tropical cyclone has winds of 86–110 kn (99–130 mph; 157–200 km/h), while the maximum rating is a category 5 severe tropical cyclone, which has winds of at least .
tropical cyclone scales