|
Ocean Seasons
July 1994
Ocean seasons are measured by comparing seasonal
variations in sea level to the yearly average. The highest
sea level -- shown as the large areas of red in the fall
image -- is caused by summer heating of the upper ocean in
the northern hemisphere. The lowest sea level -- seen as
blue and purple -- occurs off the east coast of landmasses
during spring in the northern hemisphere. This is the result
of winter winds blowing off the continents and removing
large amounts of ocean heat.
In the tropics, the sea level is primary controlled by
wind. The seasonal sea-level change in the Indian Ocean,
greatest of the three oceans, is controlled by seasonal
monsoon winds.
TOPEX/Poseidon data show how heat storage changes from
season-to-season. We discovered that the average seasonal
sea-level change is about twice as large in the norther
hemisphere as in the southern hemisphere -- partly the
result of the larger oceanic areas in the southern
hemisphere, which moderate seasonal changes.
NASA/JPL/Caltech
JPL Identification #: P-44074
|
