Thermohaline or Deep Ocean Circulation draft

Image courtesy of Maury Project, American Meteorological Society

North Central Atlantic Ocean Sample Data

Depth (meters)	Temperature (°C)	Salinity (0/00)	Density (g/mL)	Water Mass Name
100	15.0	36.0	1.0267
500	4.0	34.2	1.0273
1000	10.0	35.8	1.0276
2000	4.0	34.9	1.0283
4000	0.0	34.7	1.0281

Water Mass Identification Chart

Per Student: Graph paper, Atlantic Ocean profile

Explain: This water sample (see above tables) is taken from a vertical drop of a CDT instrument off a vessel in the Central North Atlantic. The ship stays over one place and lowers the instrument down to the bottom. As the CDT rises, an operator collects water from specific depths. This water is analyzed for different chemical features.

1. 
   Make a graph of the temperature and salinity data from the table. On the x-axis list the salinity (33.5 – 36.5 parts per thousand) and on the y-axis list the temperature (-0.2 – 20.0 °C). Note the variations of the plots. Discuss why the water taken from one place may have such differences.
   
2. 
   Use the Water Mass Identification Table to identify the water mass name.
   
3. 
   Fill in the water mass name on the Atlantic Ocean Profile.
   
4. 
   Use a world map to discuss where the waters masses might be formed based on their names.
   
5. 
   Discuss: What environmental or atmospheric factors cause the formation of the different water masses? Why are some in the Polar Regions and others in the equatorial? What might account for the subtle variations in density between the water masses? What might be at the bottom of the northern Atlantic Ocean that would channel the newly formed North Atlantic Deep Water as it moves along the bottom?
   

• 
  Research the Atlantic Ocean water mass formation.
  
• 
  Predict what might occur in the Pacific. How might the large area of the southern Pacific affect the formation of the AABW?
  
• 
  Investigate why the Arctic Ocean does not contribute to the formation of water masses.
  
• 
  View the CDT data from Pine Island Ice Shelf and the Continental Shelf. (The data in the spreadsheet shows the first two columns are from Pine island bay near Pine island ice shelf (75S,103W), the other is from the continental shelf break (71S,110W). WAITING ON APPROVAL for use.