Global Sea Surface Temperatures:

Directions: Go to the sea surface temperature image page.  Your teacher has the web site address.
A) Save every global sea surface temperature image as either a TIFF or a PICT.
B) Use image processing software to create a animated movie.
C) Answer the questions below.  To answer some of the questions, you will need to use the following formulas:
Temperature conversion from DN Value to degrees Celsius: C = (255 - DN) * .15 - 2.1
Temperature conversion from degrees Celsius to degrees Fahrenheit: F = 1.8 * C + 32


1)  What color represents the warmest ocean tempertures?  What color represent the coldest ocean tempertures?
 
Although they may vary their answers with their interpretation of the colors (you will have to use your judgement on that), red represents the warmest temperatures and purple represents the coldest temperatures.

2) In what ocean do the annual sea surface temperatures seem to vary the most?  In what part (North, Central, South) of that ocean?

They should answer either the South Pacific or the Central Pacific Ocean.

Load the 1982 image only.  In NIH or Scion Image, choose the Analyze option from the menu bar, then select Measure.
3) What does the "Minimum Value" represent?

They can answer it represents the lowest pixel value on the map, or it represents the highest temperature value for 1982.

4) What is the Surface Water Temperature (In degrees Celsius) of the "Minimum Value"?

31.35 degrees Celsius

5) The "Mean" is the average of all the pixel values in the image.  Does the value for the "Mean" represent the DN Value for the average Surface Water Temperature in that image?  Why or why not?

No it does not; since all of the land values are also included in the image (and thus in the Mean), any temperature calculated from the Mean would be incorrect.

From the Tool Box, select the Box tool.  (It should be the first tool in the second column.) Place the cursor in the image so that the X value equals 0, the Y value equals 90 (NOTE: the Y value represents the equator).  Draw a rectangle that is 90 pixels long and 45 pixels wide.  Now select Measure from the Analyze option of the menu bar.  Your box will be the correct size if the area of the box is 4050 square pixels.

6) What are the Mean, the Minimum Value, and the Maximum Value?

Mean: 71.04  Min. Value: 32   Max. Value: 163

7) What temperature (in degrees Celsius) corresponds with the Mean, the Minimum Value, and the Maximum Value?

Mean: 25.494   Min. Value: 31.35   Max. Value: 11.7

8) What temperature (in degrees Fahrenheit) corresponds with the Mean, the Minimum Value, and the Maximum Value?

Mean: 77.8892   Min. Value:  88.43   Max Value: 53.06

9) Load the image from 1992.  Repeat the directions above question 6, and answer questions 6, 7, and 8 for the 1992 image.  Fill in the table below with your answers.
 
 
1992 South Pacific Chart Data Number (Value) Degrees Celsius Degrees Fahrenheit
Mean: 70.13 25.63 78.1349
Minimum Value: 32 31.35 88.43
Maximum Value: 148 13.95 57.11

10) Which of the two years (1982 or 1992) was a cooler year in the South Pacific?  By how many degrees? (both Celsius and Fahrenheit)

1982 was cooler by .136 degrees Celsius, or .2457 degrees Fahrenheit