The OceansNov. 18

Topics

•Thermohaline circulation–SST; –ocean water masses

•Wind-driven circulation–Wind-driven upwelling–Surface currents

Mundus SubterraneusA. Kirchner, 1665

Temperature 0m

Stephens et al., NOAA, 2002

Salt content of the oceans

• Source: leaching ions from crustal material. Global river dissolved load is ~0.1 ppt. Residence time: 108yr

• Salinities for the open ocean fall in the range 33-38ppt (parts per thousand, mass per unit mass)

http://omp.gso.uri.edu/doee/science/physical/salt5.gif

Salinity 0m

Water masses {sort of like air masses}

http://earth.usc.edu/~stott/Catalina/images/weatherimages.jpg/airmasses.jpg

Arctic sea ice

http://www.ccpo.odu.edu/~arnoldo/ocean405/arcticdrift.jpg

At 70N, Tromsö and Hammarfest ice-free year-round

February September

Deepwater formation processes

http://puddle.mit.edu/~helen/oodc.html

1. preconditioning

2. Violent mixing

3. Sinking and spreading

Where it happens

Zonal average Temperature and salinity

Levitus, 1984

Tem

pera

ture

salin

ity

Transport units:

smSv /1011 36

Spatial distribution of deep and bottom water masses

(Lynne Talley, SIO)

Model of the overturning circulation

Broecker, 1980sReproduced in Ocean Circulation

Wind-driven circulation

Surface winds

Trenberth et al., JPO, 1990

tropical winds, rain

From Ocean Circulation and Climate (OCC)

Ekman transport

Transports associated with winds

Where water piles up:

Mean surface currents

Simulated sea surface temperature