currents & climate ch 14.2. warm-water currents i.e. gulf stream creates mild climate at high...

Currents & Climate

Ch 14.2

Warm-water currents

• i.e. Gulf Stream• Creates mild climate at high latitudes such

as British Isles (much warmer than Newfoundland which is at the same latitude)

Cold-water currents

• i.e. California Current• Creates cooler climate in WA, OR, CA• Much cooler than inland climates

Upwelling

• 1. surface water is blown off shore• 2. cold water from ocean floor is pulled

upward to replace the warm surface water• 3. this deep water brings nutrients from

ocean floor• 4. phytoplankton flourishes, so this helps

support healthy fisheries

El NinoEl Nino Southern Oscillation (ENSO)

• Trade winds relax• Upwelling slows on S. American coast• Thermocline is deeper• Nutrient supply decreases• Fisheries decline

Worldwide results of ENSO

• Rains less in the western Pacific• Rains more near Peru• Drought in Indonesia & Australia• Warmer, wetter winters in SE USA

El Nino

• Typically last 12-18 months• Occur every 3-7 years

Effects of El Nino

• Flash floods• Mudslides (i.e. California)• Droughts in Indonesia & Australia• Drought = crop failure

La Nina

• Cooler than normal sea-surface temps in tropical Pacific

• Easterly trades strengthen• Upwelling intensifies• Indonesia & Australia are wetter• Dries in SE USA, SW USA & Plains of

USA• Warm water is abnormally deep in W.

Pacific

Links www.classzone.com

• http://www.classzone.com/books/earth_science/terc/content/investigations/esu601/esu601page01.cfm

• http://www.cdc.noaa.gov/ENSO/#science