200 m 1000 m Fig. 31.1 (EFB)
Ocean Productivity and Circulation: Winds countercurrents Ekman spirals Langmuir cells
Fig. 2.10 (EFB)
Ekman Spiral form in hours to days Fig. 31.5 (EFB)
Langmuir Cells form in minutes to hours Fig. 31.4 (EFB)
Ocean Productivity and Circulation: Winds countercurrents Ekman spirals Langmuir cells 2. Thermohaline circulation lower temperature + greater salinity = greatest density
Ocean Productivity and Circulation: Winds countercurrents Ekman spirals Langmuir cells 2. Thermohaline circulation 3. Upwelling
Upwelling Upwelling
Normal Conditions H H March – July position of high pressure zones Cold-water upwelling intensifies
August - December position of high pressure zones Normal Conditions H H August - December position of high pressure zones Warm waters dominate inshore
Davidson Current El Niño Current
Davidson Current El Niño Current Aug-Dec shift
H H March shift in El Niño Southern Oscillation (ENSO) Cold-water upwelling absent
ENSO Early Warning Signs Higher SSTs, track Kelvin wave W to E Absence of cold-water upwelling on California coast Unusual marine organisms barracudas, mako sharks, tropical fish to north Failure of nesting seabirds
ENSO Global Impacts Droughts in interior continents: Southwest U.S., SE Asia, Australia, S. Africa Floods in coastal CA, Peru More tropical storms, hurricanes in Pacific Decline in fisheries
H H March shift in La Niña year following ENSO event Cold-water upwelling intensified
La Niña Global Impacts Intensified cold-water upwelling More tropical storms, hurricanes in Atlantic Increase in fisheries
ENSO in Antarctica = more sea ice = more productivity