EARTHSC 2GG3 Lecture Notes - Lecture 15: Icelandic Low, Azores High, Atlantic Ocean
31 Oct 2013
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Document Summary
Earth"s atmosphere is subject to cyclic changes (seasonal cycles) Many cyclic changes have impact on weather-related hazards. Heat building during daytime hours can cause afternoon thunderstorms and tornadoes (daily cycle) Climate controlled hazards are part of seasonal cycles: hurricanes occur from summer through fall, tornados occur from spring through summer. The earth is not closer to the sun in summer. Two hemispheres of earth experience summer at different times. Other observed cyclic changes in northern hemisphere climate may be explained by: changes in ocean currents, changes in solar radiation caused by changes in earth"s orbit, changes in atmospheric composition. Oceanic circulation in equatorial pacific usually is pushed westward by trade winds. This cycle happens approximately every six years. Warm surface water off peru is blown westward and replaced by upwelling of cold, deep, nutrient-rich water. This type of water is very good for fisheries. Different shifts in local climatic conditions result from the shifts in local climatic cycles.
