The goal of this lab is to learn more about the sea floor, how it is mapped, and sources of bathymetric data. You will use information and maps available through the web plus information in the class...

The goal of this lab is to learn more about the sea floor, how it is mapped, and sources of bathymetric data. You will use information and maps available through the web plus information in the class notes. Please work in teams of two. The work can be completed using any computer with a web browser and access to the Internet. The work should take about three hours to complete.
The shape of the sea floor is important to physical oceanography. The shape of the sea floor, and the depth of water influences circulation in the ocean. Sills separate deep ocean basins, sea mounts disrupt currents and tidal flows and this helps mix the ocean waters, and the relative thinness of the water constrains the flow to be mostly two-dimensional.

The Problems

Please help Captain Nemo and Professor Numero Uno solve their problems. In writing your report to them:
* Please document and justify your recommendation.
* This includes, but is not limited to:
* What information do they obtain from the maps or data sets of ocean depth?
* Which maps or data sets did you consider?
* Which maps or data sets can provide the information needed by Captain Nemo and Professor Uno?
* Can you trust the map or data sets? That is, can you recommend a particular map or data set with high degree of confidence?
1) Captain Nemo must take his submarine from offshore Manila to offshore Seattle while staying submerged at 1000 m. He asks you, his navigation team, what maps, charts, or data set he should use to avoid running aground on a seamount. He points out he must make the journey without sonar, and that the on-board inertial navigation system has an accuracy of 1 km in the horizontal and 1 m in the vertical. (30 points)
2) Professor Numero Uno has a contract to develop a global, numerical, model of the ocean's circulation. The model requires oceanic depths every 0.25 degrees of latitude and longitude. What data set should he use and why? Please contrast and compare the recommended data set with other possible data sets. (30 points)

Sources of Information

Deep ocean mapping in this country is coordinated through the NOAANational Geophysical Data Center (http://www.ngdc.noaa.gov/ngdc.html). See especially their pages onBathymetry and Topography (http://www.ngdc.noaa.gov/mgg/bathymetry/relief.html), andOcean Geosciences (http://www.ngdc.noaa.gov/mgg/mggd.html). Much of what you need can be obtained through them, or from web pages linked from their site.

Global Seafloor Topography from Satellite Altimetry(http://www.ngdc.noaa.gov/mgg/announcements/announce_predict.html). For many purposes, the most complete and accurate global maps of the sea floor are those produced by combining satellite altimeter and ship echo-sounder data. If you want to learn more about the maps and how they were produced, read Sandwell and Smith's paper onGlobal Bathymetric Prediction for Ocean Modeling and Marine Geophysics(http://topex.ucsd.edu/marine_topo/text/topo.html) and go toNGDC/WDC A for MGG - Predicted Global Seafloor Topography Information(http://www.ngdc.noaa.gov/mgg/announcements/announce_predict.html) and read the paper onExploring the Ocean Basins with Satellite Altimeter Data(http://www.ngdc.noaa.gov/mgg/bathymetry/predicted/explore.HTML) by Sandwell and Smith on how altimeters are able to observe bathymetric features.

Before writing your recommendations answer the following questions (40 pts):

1. Are data from the World-Wide ship echo-sounder data base sufficient to map all important sea-floor features?
2. What important subsea feature or features were missed in the example cited in Sandwell and Smith's paper on "Global Bathymetric Prediction for Ocean Modeling and Marine Geophysics"? Can you cite specific examples?
3. Where are the missing features located? Note latituded/longitude and name of the oceanic area.
4. Who distributes global bathymetric data sets based on altimetric and ship data? In what form are they distributed?
5. What oceanic areas were NOT mapped by this technique?
The5 Minute Topographic Map ETOPO-5(http://www.ngdc.noaa.gov/mgg/global/etopo5.HTML) was produced from ship echo-sounder data.
6. What is contained in the data set?
7. What is the original source for data in the set?
8. Who collected, edited, and processed the original data used to produce the data set?
9. Over what times periods were data obtained?
10. Over what area?
The2 Minute Map of Earth(http://www.ngdc.noaa.gov/mgg/image/2minrelief.html) and 1 Minute Map (http://www.ngdc.noaa.gov/mgg/global/global.html), land and sea produced by the National Geophysical Data Center.
11. How do these maps differ from the ETOPO-5 maps?
12. Are they more accurate, or more complete?
TheGeneral Bathymetric Chart of the OceanGEBCO (http://www.gebco.net/ was produced by digitizing hand drawn contour plots of depth calculated from echo-sounder data by international teams of hydrographers. Further information is available through theGEBCO website ((http://www.gebco.net/).
13. How does this map differ from the ETOPO-5, 2, and 1-Minute maps?