Homework Set 8 Oceanography 600
Due 4 May 2004

Late homework will cost 15 points per week or part of a week it is late.
Each question is worth 25 points.

1. Tides. Go to NOAA National ocean Service PORTS web page. Select Houston/Galveston, to get this list of plots. Select 3 days WL/Met for the Pleasure Pier at Galveston.
   1. Where is the tide gauge located?
   2. What is shown on the plot?
   3. What is the height of the highest and lowest tide?
   4. Does the predicted tide agree with the observed tide?
      1. If not, how big is the difference?
      2. What might explain the difference?
      3. Could the difference be due to the wind? (A mini storm surge?)
   5. Now go back to the PORTS web page, and select San Francisco. From the list of plots, select the 3 days WL/Met for the Golden Gate.
      1. Where is the tide gauge located?
      2. What is the height of the highest and lowest tide?
      3. Does the predicted tide agree with the observed tide?
         1. If not, how big is the difference?
         2. What might explain the difference?
         3. Could the difference be due to the wind? (A mini storm surge?)
      4. Is the tide range greater or less than Galveston?
         1. Why are they different
2. Sea Level. Sea level changes slowly due to global climate change, and to geological processes that change the vertical height of the land, and to human influences such as pumping water or oil from below the coast causing the land to settle.
   1. Go to NOAA Sea Levels Online. Select Texas, than Galveston Pier 21.
      1. How much has sea level changed in the past 90 years?
      2. What is the rate per year?
   2. Go back to the Sea Levels Online and select California, then San Francisco.
      1. How does the change compare with Galveston?
3. Ocean Waves. NOAA forecasts ocean wave heights. Go to NOAA Wavewatch III.
   1. Select Latest Model Run, wave height, nowcast. (The page default values). Select Atlantic Ocean From Global.
      1. Where are the biggest waves? Please give latitude and longitude. Don't say "in the north Atlantic."
      2. How high are they?
      3. Do you expect high waves in this region? Why?
      4. Go back and click on wind speeds for the Atlantic Ocean from Global nowcast.
      5. Are the biggest waves associated with the strongest winds?
      6. How fast are the winds in the vicinity of the maximum waves?
   2. Repeat for the Pacific ocean.
      1. Where are the biggest waves? Please give latitude and longitude. Don't say "in the north Pacific."
      2. How high are they?
      3. Do you expect high waves in this region? Why?
   3. What is a Nowcast?
   
   
4. Ocean Currents. The US Navy produces daily maps of ocean currents for all areas of the ocean. Maps for some areas are available through their Real Time Ocean Environment web page. Go to that page, and click on the Gulf of Mexico.
   1. Click on NLOM SSH Total plot (Navy Layered Ocean Model, Sea Surface Height, total height).
      1. What is shown on the plot. What are the highest and lowest values of sea-surface height in this region?
      2. If currents flow such that high water levels are to the right when looking downstream, draw in the direction of the flow. Compare your map to the map from the Naval Coastal Ocean Model to look at a plot of surface current over SSH plot for the Gulf of Mexico
      3. Now go back to the Gulf of Mexico page and click on MODAS SST (Modular Ocean Data Assimiltion System, Sea Surface Temperature) to bring up a new image.
         1. What is shown on the plot? What are the minimum and maximum values?
         2. Is the information on this plot related to the data on the last plot?
         3. Are sea level and temperature related. You may wiish to go the Naval Coastal Ocean Model to look at a plot of surface current over SST plot for the Gulf of Mexico.
   2. To find out more about the currents in this region go to the Ocean Currents for the Atlantic at the Rosenstiel School of Marine and Atmospheric Science.
      1. What are the names of the currents you saw on the last two plots?
      2. How are currents in the Gulf of Mexico related to the Gulf Stream?

Revised on: 5 September, 2004