BathymetryMap Lab HW
docx
keyboard_arrow_up
School
El Camino Community College District *
*We aren’t endorsed by this school
Course
10
Subject
Geography
Date
Feb 20, 2024
Type
docx
Pages
6
Uploaded by ChancellorScienceNightingale40
Bathymetry Maps Lab
Exercise
One:
Calculating
depth
of
water
An oceanography team of scientists conducts an experiment on the warm water of southern CA to find the depth of ocean. Following a sound explosion at 10:23:30 am, a hydrophone (receiver) records the arrival of sound on the ocean surface at 10:23:36. If the speed of sound in ocean water with the temperature of 60 °F is 4814 ft./sec, calculate the depth of ocean.
Formula: Depth = speed of sound in 60 °F seawater * (1/2) time.
If speed of sound in 60 °F= 4814 ft/sec Follow a sound exclusion at 10:23:30 am Hydrophone records the arrival of the sound on the ocean surface at 10:26:36 am So, time duration between sound explosion and the recording is: 10:23:36-10:23:30=6 second And Depth=speed of sound in 60 °F x (1/2)time : 4814 x (6/2)= 4814 x 3= 14442 ft Exercise
Two:
Drawing
Isobaths
on
a Map
Use the map on the last page to complete this exercise.
The depth sounding values are given in the bathymetric map (right) are in meters. Your task will be to draw the bathymetric isobath (contours) for this map (next page) at the I0-meter interval, i.e. the contours, to be drawn will be for the depths of 10, 20, 30, 40, 50 meters.
Exercise 3: Working with online maps
Step 1:
Visit NOAA's
National Centers for Environmental Information Bathymetric Map Viewer
.
Figure 1 source:
"Bathymetric Map Viewer"
by
NOAA/National Centers for Environmental Information
is in the
Public Domain
Uncheck:
Multibeam Surveys
NOAA NOS Hydrographic Data
And make sure this feature is checked:
DEM Color Shaded Relief
Your map should now look like this:
Figure 2
source:
"Bathymetric Map Viewer"
by
NOAA/National Centers for Environmental Information
is in the
Public Domain
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
- Access to all documents
- Unlimited textbook solutions
- 24/7 expert homework help
Step 2
Now, hover your mouse over the "?" next to the "DEM Color Shaded Relief" option. A window will pop up with a lot of information on it. What you want is the color scale that is located at the bottom. The colors represent water depth, with orange and yellow representing shallow water and very dark blue deep water.
Your screen should look like this:
Figure 3 source:
"Bathymetric Map Viewer"
by
NOAA/National Centers for Environmental Information
is in the
Public Domain
Take a look at where the colors are on the seafloor, and answer the following on the worksheet:
1. Where is the shallow water located? Hudson Bay is where the shallow water is located.
2. Where is the deepest water located? The deepest water is located in the Mariana trench in the North Pacific.
Step 3
Next, go to the upper right corner and click on options, then check the box next to "Regional Bathymetric Contours (from GEBCO_2019).
Your screen should look like this:
Figure 4 source:
"Bathymetric Map Viewer"
by
NOAA/National Centers for Environmental Information
is in the
Public Domain
Note how the contour lines with the lower numbers relate to the shallow areas, and the ones with higher numbers correspond with deeper water.
Let's take a minute to talk about where all this data came from. Recall the window that you opened up in Step 2 (figure 3). The NCEI gathered data from
NCEI-stewarded DEMs
,
GEBCO_2014
,
IBCAO
,
IBCSO
, and the
Hawaiian Island Multibeam Synthesis (University of Hawaii)
to make the colored bathymetry shown on the map, and the contours came from GEBCO 2019. Remember the videos from the
Introduction
page? All that data was collected either in a manner similar to the methods described in the videos, or from other sources, like satellites.
Figure 2 Use with Exercise 3
Step 4
Use Figure 2 below. The island at the center of the image on your screen (above map) is Santa Catalina. Zoom in on it, and uncheck the DEM Color Shaded Relief box. A screenshot is not being provided so you can play around with the settings yourself.
3. Look at the contour lines (isobaths) on the south side of the island, between the words "Catalina Island" and "Catalina Escarpment" (let's call this A), and those on the southeast side, between the words "Catalina Island" and the index map on the lower right corner of the map (we'll call this B). Which area is steeper, and which is gentler? How did you determine this (ie, which rule did you use)? The area between the words "Catalina Island" and "Catalina Escarpment" is steeper than the area between the words "Catalina Island" and the index map on the lower right corner of the map This is because the isobaths in area A are closer together, which means that there is a greater change in depth over a shorter distance. The isobaths in area B are farther apart, which means that there is a smaller change in depth over a longer distance.
4. Look again at the southeast side, between the words "Catalina Island" and the index map on the lower right corner of the map (B). Using the rules of isobaths, is this feature a canyon, or a ridge? The feature on the southeast side of the island (B) is a canyon. This is because the isobaths in this area are V-shaped, which is a characteristic of canyons. The isobaths in this area also become closer together as they move into the center of the feature, which is another characteristic of canyons.
5. Look at the contour lines (isobaths) on the southwest side of the island, between the words "Catalina Island" and "Catalina Canyon" (C). Assume the words "Catalina Canyon" aren't there. Using the rules of isobaths, how could you tell that this is a canyon?
The area on the southwest side of the island (C) is a canyon. This is because the isobaths in this area are V-shaped, which is a characteristic of canyons. The isobaths in this area also become closer together as they move into the center of the feature, which is another characteristic of canyons.
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
- Access to all documents
- Unlimited textbook solutions
- 24/7 expert homework help