Ch 24.3 Winds

Weather is the horizontal movement of air.

Air always moves from H L pressure.

Temperature differences create pressure differences.

Local Winds: Sea & Land Breezes

http://www.classzone.com/books/earth_science/terc/content/visualizations/es1903/es1903page01.cfm?chapter_no=visualization

Local Breezes – over short distancesEx.: Sea breezes – happen during the day because LAND Heats Up FASTER THAN WATER (water takes a long time to heat up and cool down).

Local Breezes – over short distancesEx.: Land breezes – happen at night because LAND COOLS DOWN FASTER THAN WATER.

Air is mostly heated by I.R. re-radiated off of surfaces. Warmer surfaces Warmer air Less dense (more expanded) Low PressureCooler surfaces Cooler air Denser High PressureWind moves from H L pressure

Air is mostly heated by I.R. re-radiated off of surfaces. Warmer surfaces Warmer air Less dense (more expanded) Low PressureCooler surfaces Cooler air Denser High PressureWind moves from H L pressure

Local Breezes – over short distancesEx.: Land breezes – happen at night because LAND COOLS DOWN FASTER THAN WATER.

Warm air •More Kinetic Energy •Less Dense•Low Pressure•Rises (less dense)•Room for moisture

Cold air •Less Kinetic Energy •Denser•High Pressure•Sinks(denser)•Dry (less room for moisture)

MOONSOON RAINS are seasonal and experienced in India & S.E. Asia (subtropical locations)

Summer – Land in warmer (Low Pressure) than Water (High Pressure). Air moves from water to land carrying moisture --- RAIN.

It can rain 37 ft of rain in a few months.

Remember … Land heats up faster than water.

Winter – Land is cooler than water. Air moves from land to water – this is a DRY SEASON

Seasonal Winds: Monsoon Winds

GLOBAL WINDS – DUE TO DIFF. IN PRESSURE

Warm air rises at the equator and cold dense air sinks at the poles. In general wind want to move from Poles Equator, but E’s rotation CURVES the path of wind.

CORIOLIS EFFECT – DUE TO EARTH’S ROTATION, CURVES THE PATH OF THE WIND.

Wind & Surface Currents deflect TO THE RIGHT in the N. Hemi; TO THE LEFT in the S. Hemi.

WARM AIR RISES – LOW PRESSURE

COOL AIR SINKS – HIGH PRESSURE

http://www.classzone.com/books/earth_science/terc/content/visualizations/es1905/es1905page01.cfm?chapter_no=visualization

http://www.mhhe.com/biosci/genbio/tlw3/eBridge/Chp29/animations/ch29/global_wind_circulation.swf

Global Winds

http://www.coolschool.ca/lor/GEO12/unit9/U09L03.htm

Global Winds: Warm Low Pressure Air (carrying moisture) Rises @ Equator and Sinks @ 30 N & S (dry, sinking, high pressure air)

http://www.ukdivers.net/meteorology/coriolis.htm

Global Winds: There are 3 major convection cells of rising and sinking air for each hemisphere.

Due to Coriolis: Air deflects to the Right in the N. Hemi. And to the Left in the S. Hemi.

Remember: start at the BASE of the arrow.

Winds Aloft (high in Troposphere)JET STREAM – •Rivers of wind high in the atmosphere - above about 20,000 feet (Tropopause: Boundary of Tropo. & Stratosphere)•Also help determine the locations of areas of high and low air pressure at the Earth's surface. •Steers Weather.•Jet stream dips south … we get cold Canadian air•Jet stream slides north … warm Gulf air rides up.

Jet Stream:http://www.wunderground.com/US/Region/US/pxJetStream.html

http://www.pbs.org/wgbh/nova/vanished/jetstr_giving.html

Current Jet Stream Animations:http://www.wunderground.com/global/Region/EU/pxJetStream.html