Topic Guide:  Atmosphere and Ocean Interactions

 

In this activity you will form groups, conduct research into atmosphere and ocean interactions, and report back to your lab section in the form of a presentation. At the end of this activity you will find suggestions for the format of the presentation. You will use the data you investigate as evidence for your statements. Please use these suggestions and the “How to make a class presentation” (Resource 1) as guidelines for your presentation.

 

Overview:

The atmosphere regulates how we experience the Earth's climate and weather. The oceans exert a very strong influence on the atmosphere,and thus our weather and climate. Water has a relatively high heat capacity, which means that it takes a relatively large amount of heat to change the temperature of the ocean. The result is that its temperature does not change quickly, so acts as a global "flywheel" that reduces the effect of shorter term daily and seasonal changes in the atmosphere. This is seen in the difference between coastal and intercontinental temperature swings between seasons. Evaporation from the ocean to the atmosphere transfers moisture and heat to the atmosphere, where it is carried to other regions, generally northward. These processes also determine the location of major dry and wet latitudes (climate zones) and regions of persistent cloudiness.

 

The El-Nino is one of the best known ways the ocean and atmosphere interact to change the climate globally. Changes in the sea surface temperature and their interaction with the atmosphere cause droughts, storms and other extreme weather events around the world.

 

Key processes and concepts to review before beginning:

Resources:

 

After completing this investigation you should be able to:

1. Explain and understand the basic relationships between sea surface temperature (SST), winds, evaporation, and precipitation
2. Explain some of the ways that the Earth’s atmosphere and oceans interact.
3. Explain data that helps us understand how heat is transferred to higher latitudes.

 

You can go straight into exploring the data, but if you need more background information about atmosphere and ocean interactions, please review the websites that provide background information (found after the data section).

 

Data, Sea Surface Temperatures:

First look at data included in the Atmosphere dataset on the WorldWatcher CD. Go to the Geography Dataset. Double click on the word “Atmosphere.” Click on the “Surface Temperature” button and select “Make a Movie from Datasets.”

 

 

We already looked at surface temperature dataset in the WorldWatcher tutorial, but we will now look at it more closely since there are some interesting patterns that we have not yet explored. Step through the data from January to September.

Describe how the surface temperatures vary with latitude, and how they vary throughout the year at various latitudes. Pay particular attention to the poles and the equatorial region.

 

First concentrate on the Northern Hemisphere. Step through from January to September. What do you notice about the latitudinal extent of the cold region as compared to the Southern Hemisphere?

 

Why does this occur? A hint: does the effect depend on the type of surface beneath?

 

Now watch the Northern Hemisphere as we slowly progress from January to February to March to April. Do the temperature changes progress or regress evenly? If not what is your explanation for your observations?

 

Look at March and April. What are these remaining pockets of cold temperatures? Why are they there?

 

Now look at the Southern Hemisphere. Step through the animation data from January to February to March to April. What is the general pattern that you see?

 

Is it an even progression/regression?

 

Can you think of a reason for this pattern?

 

Step through the animation data from May to June to July looking at the South American continent. What do you see happening?

 

Why is this happening?

 

Data, Surface Winds

The next WorldWatcher dataset we will look at is the surface wind speed. What patterns do you see as you step through the months January to July? Compared with the other datasets you have seen, these relationships may not be exceptionally clear. Please refer to your textbook for additional information about climatic winds (Chapter 7 in Segar).

 

Can you see a strengthening or weakening of any particular patterns as you step through the months from January to July?

 

First concentrate on the Southern Hemisphere. There is a clear band of wind at the circling the Earth and crossing at the tip of South America. Does this surface wind strengthen or weaken as we progress from January to July?

 

What is this band of surface winds called?

 

Are there any well-developed bands of wind in the equatorial region? Why or why not? You can refer to your textbook for more information concerning this topic.

 

As you move to the Northern Hemisphere, just above the equator, look at the data for June and July.  What is happening off the coast of India and Saudi Arabia? This is a condition that called “monsoon” winds. Refer to your textbook (or the “Indian Monsoon” mini-study) for more about the Indian monsoon.

 

What happens to these regions during the monsoon?

 

What is happening to the wind patterns in the northern portion of the Northern Hemisphere from January to March? Are bands of wind becoming stronger or weaker? Please offer an explanation for why this happens and also if this pattern differs from that found in the similar latitudes in the Southern Hemisphere. Hint: compare January to July.

 

Look at the Surface Evaporation data on the WorldWatcher CD. Use the scale bar to determine what designates areas of high surface evaporation and what denotes areas of low surface evaporation.

 

These data are a little more complicated, so step through the months, January to July, and concentrate on the Southern Hemisphere first. As you progress from January to July, what does the change in the overall pattern of the distribution of surface evaporation look like?

 

 

Why do we see this pattern? Hint: remember the seasons are different in the different hemispheres.

 

Notice that there are areas in the southern portions of the continents of South America, Africa and Australia where surface evaporation is low, but precipitation is also low. What do we call these areas (general name of biome or specific names of the regions are fine)? Please offer an explanation for why they are located where they are.

 

Now concentrate on the Northern Hemisphere. Step through from January to July. What overall changes are happening?

 

As you step through the data, you should have noticed that there are several regions where the overall surface evaporation remains very low. These areas include a region in Northern Africa, a region in central Asia, and Greenland. These are also areas of very low precipitation. What do we call these areas in Northern Africa and the region in central Asia (please give me the specific name of these large, well known areas)?

 

Why they are located where they are.

 

Is this explanation different or the same for why Greenland is experiencing the same parameters?

 

Additional data explorations with Worldwatcher:

Investigate precipitation patterns and how they relate to sea surface temperature and major wind belts.

 

Additional Data Sources:

Additional data to consider is sea surface temperature (SST) and precipitation. These are in the WorldWatcher and on the web (links below).

 

Sea Surface temperature

Sea Surface temperature data archives: http://Earthobservatory.nasa.gov:81/Observatory/Datasets/sst.avhrr.html

http://weather.unisys.com/surface/sst.html

 

Background information:

Information about sea surface temperature

http://www.csc.noaa.gov/crs/definitions/SST.html

 

Presentation Framework:

Your presentation should include a brief overview explaining the significance of atmosphere and ocean interactions. You should then choose as many of the following topics as is necessary to explain the concept. Choose topics that you think might be relevant to understanding how the atmosphere and ocean interact. Your presentation should include interesting findings from your investigations, backed up with data. You must use the physical data in your presentation.

 

You may choose from the following list of topics, or investigate a topic of your own. The topics in the list are examples of investigations that could be made using the data available at the URL’s listed above.

 

Data driven topics:

 

Overview type topics:

• Global atmospheric circulation patterns