Gulf Stream, ENSO, Climate, and up and downwelling
Upcoming SlideShare
Loading in...5

Gulf Stream, ENSO, Climate, and up and downwelling






Total Views
Views on SlideShare
Embed Views



0 Embeds 0

No embeds



Upload Details

Uploaded via as Microsoft PowerPoint

Usage Rights

© All Rights Reserved

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
Post Comment
Edit your comment

    Gulf Stream, ENSO, Climate, and up and downwelling Gulf Stream, ENSO, Climate, and up and downwelling Presentation Transcript

    • Gulf Stream Best studied of all ocean currents Meanders and loops Merges with Sargasso Sea  Circulates around center of North Atlantic Gyre  Unique biology – Sargassum© 2011 Pearson Education, Inc.
    • Gulf Stream Meanders or loops may cause loss of water volume and generate:  Warm-core rings – warmer Sargasso Sea water trapped in loop surrounded by cool water  Cold-core rings – cold water trapped in loop surrounded by warmer water Unique biological populations © 2011 Pearson Education, Inc.
    • El o – Southern Oscillation (ENSO) High pressure in eastern Pacific weakens Weaker trade winds Warm pool migrates eastward Thermocline deeper in eastern Pacific Downwelling Downwelling Lower biological productivity  Peruvian fishing suffers © 2011 Pearson Education, Inc.
    • ENSO Conditions in the Pacific Ocean© 2011 Pearson Education, Inc.
    • La a – ENSO Cool Phase Increased pressure difference across equatorial Pacific Stronger trade winds Stronger upwelling in eastern Pacific Shallower thermocline Cooler than normal seawater Higher biological productivity Stronger upwelling © 2011 Pearson Education, Inc.
    • a Conditions© 2011 Pearson Education, Inc.
    • Occurrence of ENSO Events  El Niño warm phase about every 2–10 years  Highly irregular  Phases usually last 12–18 months  10,000-year sediment record of events  ENSO may be part of Pacific Decadal Oscillation (PDO)  Long-term natural climate cycle  Lasts 20–30 years© 2011 Pearson Education, Inc.
    • ENSO Occurrences© 2011 Pearson Education, Inc.
    • ENSO has Global Impacts© 2011 Pearson Education, Inc.
    • Notable ENSO Events 1982 – 1983  1997 – 1998  Flooding, drought, erosion, fires, tropical storms, harmful effects on marine life  Unpredictable© 2011 Pearson Education, Inc.
    • Predicting El o Events  Tropical Ocean−Global Atmosphere (TOGA) program  1985  Monitors equatorial South Pacific  System of buoys  Tropical Atmosphere and Ocean (TOA) project  Continues monitoring  ENSO still not fully understood© 2011 Pearson Education, Inc.
    • Ocean Currents and Climate Warm ocean currents warm the air at the coast.  Warm, humid air  Humid climate on adjoining landmass Cool ocean currents cool the air at the coast.  Cool, dry air  Dry climate on adjoining landmass © 2011 Pearson Education, Inc.
    • Upwelling and Downwelling Upwelling – Vertical movement of cold, nutrient-rich water to surface  High biological productivity © 2011 Pearson Education, Inc.
    • Downwelling – Vertical movement ofsurface water downward in water column
    • Coastal Upwelling Ekman transport moves surface seawater offshore. Cool, nutrient-rich deep water comes up to replace displaced surface waters. Example: U.S. West Coast © 2011 Pearson Education, Inc.
    • Other Types of Upwelling Offshore winds Seafloor obstruction Coastal geometry change © 2011 Pearson Education, Inc.
    • Coastal Downwelling Ekman transport moves surface seawater toward shore. Water piles up, moves downward in water column Lack of marine life © 2011 Pearson Education, Inc.