ERTH 20 Lecture Notes - Lecture 5: Walker Circulation, Landfall, Wind Wave
7 May 2020
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Document Summary
Walker circulation: east-west circulation in atmosphere, driven by distribution of land masses. Tropical cyclones with sustained winds of over 120km/h. In atlantic and e pacific = hurricane. In indian ocean and australia = cyclones. Tropical disturbance: cluster of small thunderstorms. Can form: simply due to heating of air near equator, easterly wave. Hurricanes are driven by latent heat as water vapor condenses: warm and moist air provided by ocean temperatures greater than 27 degrees. Too weak at equator: no coriolis effect at the equator. Strong winds in the upper troposphere spreads hurricane out, less concentrated energy. High winds: damage structures and trees. Tornadoes: form where the hurricane makes landfall and moves inland. Heavy rain: causes flooding and some structure damage. Wind driven surge: hurricane winds pile up water near the coast. No agreement in models whether hurricanes will become more frequent. Is agreement that warmer surface ocean temperatures are likely to make hurricanes more intense when they do form.
