Images: If Rain Falls on the OceanDoes It Make a Sound?
The Great Salinity
Anomaly, a large, near-surface pool of fresher-than-usual
water, was tracked as it traveled in the subpolar gyre
currents from 1968 to 1982.
as a function of time at 10 meters, 200 meters, and 1,000
meters depth as recorded at Ocean Weather Station Bravo
in the Labrador Sea. Deep convection is possible when
the salinity difference between shallow and deep water
is small. This normally occurs every winter. However,
from 1968 to 1971, the presence of the fresh, shallow,
Great Salinity Anomaly prevented deep convection. Unfortunately,
Weather Station Bravo is no longer maintained. Scientists
will need to use new technology like the PALACE float
in order to reestablish such time series. Such data is
essential for understanding the role of freshwater anomalies
in the climate system.
is a key component of the ocean’s role in Earth’s
climate. Strong winter cooling of surface waters causes
them to become denser than water below them, which allows
them to sink and mix with deeper water. This process releases
heat from the overturned water to the atmosphere and maintains
northern Europe’s moderate winter climate. The Great
Salinity Anomaly interrupted this process as its pool
of fresher water prevented convection.
surface salinity distribution in the global ocean, as
compiled from many individual ship measurements, mostly
during this century. The figure also shows the approximate
coverage obtainable with an array of about 1,000 Slocums
or PALACES. These would resolve the large scale features
of the salinity field and provide completely new information
on its variability with time. The array would be an early
warning system for the Great Salinity Anomalies of the