ERTH 535:
Planetary Climate Change
(Spring 2018)
Lab Activity #7
(For classes starting Monday, April 2)
Dr. Dave Dempsey
Dept. of Earth & Climate Sci.,

(For access to color version of the maps in this activity, go to:

Global Patterns of Sea Surface Temperature and Salinity

Objectives:    (1) Imagine dividing global sea-surface temperature (SST) patterns into warm, cool, and cold regions. Using the blank map attatched to the end of this document, lightly draw where you think the boundaries may lie between the warm, cool, and cold areas. Why did you choose to draw the boundaries as you did?

    (2) The first two maps below (Figures 1(a) and 1(b)) show SST patterns during the months of February and August 2011, respectively. The next map (Figure 2) shows temperature differences between the two months (August minus February, 2011).

Figure 1(a): Monthly mean sea surface temperatures (°C) for February, 2011

Figure 1(b): Monthly mean sea surface temperatures (°C) for August, 2011

Figure 2: Difference between August and February 2011 sea surface temperatures (°C)

For the purposes of this activity, on Figures 1(a) and 1(b) (the February and August 2011 SST maps), define the boundary between warm and cool SST regions as the 24°C contour line, and between cool and cold SST regions as the 10°C contour line. Draw these boundaries on the February and August SST maps.

    (3) Although for the most part SST isotherms are oriented east/west, as you might expect given the decrease in absorbed solar radiation with increasing latitude, you generally should note deviations or bending of the contour lines near the edges of oceans. Can you think of a hypothesis that can account for these equatorward and poleward bends in the isotherms? What kind of data would you need to test your hypothesis?

    (4) Examine the following map of surface currents in the ocean :

    (5) Based on the patterns of SST in Figures 1(a) and (b) and the ocean surface currents shown on the map above:

    (6) Figure 3 below shows the net energy flux (in Watts/m2) into (orange colors) and out of (blue colors) the ocean surface.

Figure 3: Energy flux into (oranges) and out of (blues) the sea surface

    (7) Figure 4 below is a salinity map for August 2011. Except in isolated spots (notably in the Arctic Ocean), the oceans exhibit very little seasonal variation in salinity, so the map for February would look largely simila (again, except in the Arctic Ocean).

Figure 4: Sea surface salinity (‰) for August 2011


Images in this activity were downloaded from the National Virtual Oceanographic Data System (NVODS) at Be aware that not all Web browsers can successfully access the images at this site; see to see if your's can.


Map of the Contintents and Oceans

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