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Glossary of Chemical Oceanography Terms
Thermocline: A thermally stratified layer of surface water that separates the upper,
warmer, less- dense zone from the lower, colder, denser zone. It is the depth zone
with the largest decrease in temperature in the water column and sometimes
changes seasonally.
Thermohaline Circulation: Vertical and deep seawater circulation resulting from density
differences caused by changes in T and S.
Tidal Currents: The currents produced by daily changes in the tides.
Trades: Airflow from the east to the west in the tropics. Surface winds forming part of
Hadley cell.
Trench: A long, narrow depression with relatively steep sides; often is the deepest portion
of the ocean.
Tropics: Region of the earth’s surface lying between 23°27′ N and 23°27′ S; the Tropics
of Capricorn and Cancer are the northern and southern boundaries, respectively.
T–S Diagram: A diagram plotting the temperature (T) versus salinity (S) of ocean waters;
used to characterize water masses.
Upper Water: Area of water generally in the upper 1000 m.
Upwelling: The rising of cold, nutrient- rich bottom waters. Occurs near the western coast
of South America and Africa as the result of offshore winds.
Vertical Circulation: Positive and negative circulation with respect to the vertical axis.
Caused by density gradients as a result of differences in T and S.
Warm Core Rings: Formed in the Sargasso Sea due to Gulf Stream meandering. They are
made up of low- nutrient waters that move north.
Water Mass: A parcel of seawater that has similar properties (T- S). Each water mass type
is formed through surface climatic processes. Example: the North Atlantic Deep
Water formed in the North Atlantic.
Weathering Products: Products formed as a result of weathering from wind, ice, rainfall,
and the like at or near the earth’s surface.
Weddell Sea: Southeast of Drake Pass and the tip of South America. Site of Antarctic
bottom water formation.
West Australian Current: Waters that move north, along western coast of Australia.
West Greenland Current: Flows north, along western coast of Greenland (low salinity
and temperature).
Westerlies: Airflow at midlatitudes from the west to the east. Produced by the temperature/
pressure gradient. Surface winds form part of Ferrel cells.
Wind- Driven Circulation: Circulation caused by wind blowing over the surface of the
ocean waters. Affects the upper few hundred meters of ocean.
II. Major Components of Seawater
Absolute Salinity, S T : The salinity that represents the true amounts of salts in seawater. It
can be determined by measuring all the individual major components of seawater.
It is about 0.0165 g/ kg higher than the practical salinity S P for average seawater.
Alkalinity: The concentration of all the bases that can accept a proton when seawater is
titrated with acid to a pH of 4.0.
Anoxic Basins: Basins that contain no O 2 below a given depth. Examples include the Black
Sea and Cariaco Trench.
Glossary of Chemical Oceanography Terms
Thermocline: A thermally stratified layer of surface water that separates the upper,
warmer, less- dense zone from the lower, colder, denser zone. It is the depth zone
with the largest decrease in temperature in the water column and sometimes
changes seasonally.
Thermohaline Circulation: Vertical and deep seawater circulation resulting from density
differences caused by changes in T and S.
Tidal Currents: The currents produced by daily changes in the tides.
Trades: Airflow from the east to the west in the tropics. Surface winds forming part of
Hadley cell.
Trench: A long, narrow depression with relatively steep sides; often is the deepest portion
of the ocean.
Tropics: Region of the earth’s surface lying between 23°27′ N and 23°27′ S; the Tropics
of Capricorn and Cancer are the northern and southern boundaries, respectively.
T–S Diagram: A diagram plotting the temperature (T) versus salinity (S) of ocean waters;
used to characterize water masses.
Upper Water: Area of water generally in the upper 1000 m.
Upwelling: The rising of cold, nutrient- rich bottom waters. Occurs near the western coast
of South America and Africa as the result of offshore winds.
Vertical Circulation: Positive and negative circulation with respect to the vertical axis.
Caused by density gradients as a result of differences in T and S.
Warm Core Rings: Formed in the Sargasso Sea due to Gulf Stream meandering. They are
made up of low- nutrient waters that move north.
Water Mass: A parcel of seawater that has similar properties (T- S). Each water mass type
is formed through surface climatic processes. Example: the North Atlantic Deep
Water formed in the North Atlantic.
Weathering Products: Products formed as a result of weathering from wind, ice, rainfall,
and the like at or near the earth’s surface.
Weddell Sea: Southeast of Drake Pass and the tip of South America. Site of Antarctic
bottom water formation.
West Australian Current: Waters that move north, along western coast of Australia.
West Greenland Current: Flows north, along western coast of Greenland (low salinity
and temperature).
Westerlies: Airflow at midlatitudes from the west to the east. Produced by the temperature/
pressure gradient. Surface winds form part of Ferrel cells.
Wind- Driven Circulation: Circulation caused by wind blowing over the surface of the
ocean waters. Affects the upper few hundred meters of ocean.
II. Major Components of Seawater
Absolute Salinity, S T : The salinity that represents the true amounts of salts in seawater. It
can be determined by measuring all the individual major components of seawater.
It is about 0.0165 g/ kg higher than the practical salinity S P for average seawater.
Alkalinity: The concentration of all the bases that can accept a proton when seawater is
titrated with acid to a pH of 4.0.
Anoxic Basins: Basins that contain no O 2 below a given depth. Examples include the Black
Sea and Cariaco Trench.