Introduction to Physical Oceanography
Homework Set 4
Due 1 October 2008

Late homework will cost 15 points per week or part of a week it is late.

1. Sampling Error. On Wednesday, 17 September, you saw a few animations of changes in sea-surface temperature and height calculated from the ocean-circulation models. View this animation of sea-surface temperature in the tropical Pacific. Then answer these questions:
   1. What ideal observing system might be needed to observe changes in temperature patterns at the sea surface, either in a small region or throughout the entire tropical Pacific? Please be specific. What samples in time and space are needed to avoid important sampling errors?
   2. Now look at this map of the Tropical-Ocean Atmosphere array that measures sea-surface temperature and other variables in the tropical Pacific. Each square is the location of a buoy that measures temperature and other variables.How close does this observing systems come to the ideal?
      
      
2. Types of Flow. The Strait of Gibraltar is the passage, about 58 km long, connecting the Atlantic and the Mediterranean, between southern most Spain and northwestern most Africa. The strait's width ranges from 12.9 km off Point Marroquí to 43 km at the western entrance. The depth is about 300 meters. (From Answers.com)
   
   
   Photograph of the Strait of Gibraltar from the space shuttle, October 1984, mission STS-41G, image 17-34-81. The Atlantic Ocean is at the bottom, the Mediterranean Sea is at the top. From NASA Lunar and Planetary Institute, Houston, Texas web page on Space Shuttle Views the Earth: Human Imprints from Space.
   
   Sketch the flow through the Strait of Gibraltar assuming the sill depth is very shallow, say 5 meters, instead of 300 meters.
   1. Would you expect the flow to be that illustrated in Figure 7.1 of the class notes?
   2. What happens to the flow as the depth becomes as shallow as a say five meters?
   3. Please state reasons for your answers.
      
      
3. Coriolis Force. Many textbooks state that the Coriolis force causes ocean currents to veer to the right in the northern hemisphere. Look at the tropical circulation in figure 11.6, the Caribbean circulation in figure 11.7, and the west Greenland current in figure 11.8 in the textbook.
   1. Do any of these currents veer to the left in the northern hemisphere?
   2. Why don't they veer to the right?
      
      
4. Salt Fingering. Where in the ocean do you expect salt fingering to be important?
   1. List at least two regions.
   2. What oceanic processes lead to the distribution of salinity and temperature necessary for salt fingering in these regions?
      
      
5. Temperature Data. You are asked by an oil-production company to write a report on the surface temperatures that might be encountered by a production platform in 2 km water depth on the Texas continental slope. The company points out that temperature and currents are related, and that temperature information may be useful for designing offshore structures for the Gulf of Mexico.
   1. List two possible sources on information you could use in the report.
   2. List the advantages and disadvantages of each source.
   3. Overall, what source would you choose for your report, and why?

Revised on: 30 September, 2008