Thursday, April 3, 2008

Today we did more research. Beverly, Ling Yi and I decided to go home and source for more information before compiling the information. Here's what we have gathered so far.

Wind is simple air in motion. It is caused by the uneven heating of the earth’s surface by the sun. Since the earth’s surface is made of very different types of land and water, it absorbs the sun’s heat at different rates.
During the day, the air above the land heats up more quickly than the air over water. The warm air over the land expands and rises, and the heavier, cooler air rushes in to take its place, creating winds. At night, the winds are reversed because the air cools more rapidly over land than over water.
http://www.eia.doe.gov/kids/energyfacts/sources/renewable/wind.html


Physics of Hurricanes
Understanding the physics of the air/sea interface is a critical component of understanding hurricanes, which draw their energy from the thermodynamic disequilibrium that ordinarily exists between the tropical oceans and the atmosphere. The maximum wind velocity depends on maintaining a sensitive balance between the production of mechanical energy and frictional dissipation in the atmospheric boundary layer, which in turn depends on the fluxes of momentum and enthalpy through the sea surface. Yet little is know about such fluxes at extreme wind speeds. Kerry Emanuel of the Massachusetts Institute of Technology described recent laboratory experiments designed to better quantify flux wind speed relations and to explore possible control of the fluxes by application of molecular monolayers.

http://www.aps.org/publications/apsnews/200202/dfd.cfm

Hurricanes are nearly perfect examples of heat engines, driven by an evaporative enthalpy flux from the ocean to the atmosphere, and operating over a temperature differential of more than 100 K between the sea surface and the storm top.

http://www.physics.utoronto.ca/lecture-and-seminar-series/colloquium/events/emanuel/view