When ocean currents flow
over large distances, water of one temperature is carried
into zones of another temperature. You may be able see traces
of these currents on the map as swaths of color. Tropical
storm tracks can also be seen in sea surface temperature (SST)
data.
Over the long term, SST data can be used to study annual shifts
in ocean currents and temperatures. These changes in ocean
conditions are interconnected with seasonal weather patterns
such as monsoons and droughts. SST data are also crucial to
understanding periodic phenomena like El Niño and long-term
climate shifts attributable to global warming.
The data represented on this map come from satellite measurements
of microwave energy emitted by ocean waters. Microwave energy—like
visible light and infrared radiation—is a form of electromagnetic
radiation. Something hot—like a candle flame—gives
off visible light. Something cooler than a candle flame—like
the ocean’s water—gives off other forms of electromagnetic
radiation. The frequencies and intensities of electromagnetic
radiation emitted depend on the object’s temperature
and its electrical properties. The frequencies of microwaves
emitted by the ocean’s water were used to create this
map.
Today’s
Sea Surface Temperatures
- Shown
here are measurements of the temperature
of the sea surface today, taken by satellite.
The strip along the bottom gives the temperature
scale, ranging from ice, shown as white,
to 90¾F, shown as dark red. Source: Space
Science and Engineering Center: University
of Wisconsin-Madison
Traditionally, satellite measurements
of sea surface temperature used infrared radiation
to “see” the temperature of the ocean’s
surface. Unfortunately, overlying clouds often
blocked the infrared radiation and blocked the
view. Finally, in 1997, a satellite was launched
that measures sea surface temperature using microwave
energy, which passes easily through clouds.
related
sites
•
NASA’s
Real-Time Microwave Imaging - Shows
near-live satellite images of the earth’s
surface on a selectable range of “channels,”
or frequencies.
glossary terms
