March 18, 2009 Location, location, location

Knowing where you are, where you have been, and where you are going are very important in on the Healy. The Coast Guard needs this data for navigation. The scientist needs this data for their documentation. Where are the answers? Satellite information and sensors on the ship are constantly inputting data into mapping programs. These mapping programs then are accessible by computer to anyone on the ship.

The Healy started in Seattle, stopped in Kodiak, the large Island south of mainland Alaska. Then it continued through the Unimak Pass north to St. Lawrence island. Now it is heading SW.

The Healy started in Seattle, stopped in Kodiak, the large Island south of mainland Alaska. Then it continued through the Unimak Pass north to St. Lawrence island. Now it is heading SW.)

Look at the depth changes. The darker the blue, the deeper the water.

Let's look at images downloaded from the shipboard GIS mapping tool on the Healy developed by Steve Roberts. The first map records the ship's track from Kodiak Island, the island below the mainland of Alaska to our current location, south of St. Lawrence Island. The ship is the small red outline of a boat. Yesterday we were near St. Lawrence Island. Today we are heading for a station south of the island. Some of the red dots are stations in the Bering Sea that we stopped to collect data. Stations are stopping places, specific points in the Bering Sea.  Some places, or stations, have been studied in past years. Scientists go back and collect data from the same places so they can make comparisons over the years. Jackie Grebmeier, one of the chief scientists on board, has been collecting data from some of the stations for over 20 years.

Most red dots mark stations that we have stopped to take samples.

How deep are the waters that we are traveling? Bathymetry is the mapping of the water depths. I drew a line on the computer from the red dot near St. Lawrence Island to the ship's current location. Pretend you were able to walk along that same line but your feet must always stay on the bottom of the Bering Sea. What would you encounter? The graph below shows you the path that you walked.

The line shows the depths from the red dot near St. Lawrence Island to where the ship is currently.

Zero is the point near St. Lawrence Island. The end of the graph is the current location of the ship. How was your walk? Was it an easy one? Are you getting deeper or shallower? Did you have to walk up any hills?

Mapping sea and ocean floors is an exciting field to study if you like computers, maps, and science. Maybe you will be the next person who discovers and maps an uncharted area of the sea.

Breaking ice with mapping,

Deanna Wheeler 2009 PolarTREC Teacher