WHY IS SEA SURFACE TEMPERATURE IMPORTANT?

Earth's climate has remained essentially unchanged for centuries. This is because the amounts of heat and water from all sources that enter (input) the atmosphere must equal the amounts removed (output) from the atmosphere for the climate to remain basically unchanged. Today, emissions of gases such as carbon dioxide into the atmosphere (by humans) may be upsetting the temperature of the atmosphere necessary to maintain the balance between heat gained and heat lost. That is one problem that has scientists worried. Another is that recently scientists have been observing some global climate fluctuations that are taking place on the time scale of our human lives and seem to be linked to an oceanographic event called El Niño. Remember the severe weather associated with the powerful 1997-1998 El Niño:

• severe coastal storms, heavy rainfall, flooding and mud slides in California
• droughts in Mexico and Central America, which led to forest fires that burned for long periods of time sending heavy smoke north to the United States
• droughts in Australia that caused a shortage of water
• unusually mild winters on the east coast of the United States
• droughts in the midwest of the United States
• economic disaster to the Peruvian fisheries
• ice storms in eastern Canada and New England that caused some areas to be without power for over a month as rain froze on contact with telephone poles, power pylons, wires, and trees -- the weight of the ice caused pylons and poles to crumple and wires to break.

But, what do the oceans have to do with climate, you ask? The answer, a lot! The oceans and the atmosphere form a closely linked "dynamic duo." Energy from the Sun, plant distributions, and greenhouse gases in the atmosphere can affect temperature and circulation patterns of this ocean-atmosphere duo.

The Sun is Earth's main source of energy. Solar (Sun) energy is absorbed (taken in) by both oceans and continents (land). BUT, because the oceans cover over 70% of Earth's surface and are darker than the continents, they absorb more of the Sun's energy. Here's another big idea -- oceans not only absorb lots of energy from the Sun, they can also store lots of solar energy in the form of heat, AND they can do this with very little change in temperature. Scientists believe the way the oceans store and transport (move) heat is related to climate. One way scientists study the way the oceans store and transport heat is to look at the temperature of the oceans, specifically the sea surface temperature.

ABOUT THE LECTURE

The lecture is represented on the screen with three independent frames. The frame across the top right contains the title, buttons you can use to move between the two parts, and links to the different sections of each part. The frame below it on the right displays the text of the selected section, and buttons at the bottom also allow you to move between sections. The vertical frame on the left side presents thumbnails of all graphical figures from the selected part. Each thumbnail links to a larger image for viewing and printing. All citations for graphics and text are found in each part's References section.

Part 1: Global Sea Surface Temperature Distribution and Satellite Sea Surface Temperature Observations

Part 2: Determining SST From Advanced Very High Resolution Radiometer (AVHRR) Infrared Observations