By: Matt Rutherford On: August 26, 2015 In: Education Comments: 1

Student Responses to Ships and Satellites Together Modeling World Ocean Salinity and Temperature

Madelaine H: “Why would the warm water be deeper; isn’t normally surface water warmer?”

ORP: “Worldwide, the sea surface is where you are more likely to find warmer water due to the sun’s ability to warm the water to a certain depth. Surface mixing caused by wave action combined with surface currents can also heat up water the first 50 feet or so.  Think of a layered cake. Up here in the Arctic the top layer’s temperature is influenced by sunshine and mixing, then you have a major temperature change (thermocline) where the sun’s UV rays do not reach down enough to warm the cooler polar water, next up around 700 feet we witnessed another warm layer varied in thickness (The salty Atlantic layer), then finally you have another cooler layer all the way to the bottom. That warm salty Atlantic water traveled a long way from the North Atlantic Ocean influenced by the world wide thermohaline circulation. We managed to find it as far North as you can sail, at 78 degrees north and 650 feet below the ocean surface.

Madelaine H:  “Why does salinity change the circulation of the ocean around the world?”

NASA: “Large scale ocean circulation or thermohaline circulation (note
thermo=temperature, haline=salinity) is driven by density gradients
(density is a function of temperature and salinity). For example, the
magnitude of the Atlantic Meridional Overturning Circulation (AMOC, part
of the conveyor belt) is driven by the sinking rate of cold, salty water
in the north Atlantic. Fresher water at the surface would tend to
slowdown the sinking rate while salty water would increase it”.

Bryan W:  “Why are satellites less sensitive to salinity in polar waters?”

NASA: “Satellites, such as SMOS, SMAP and Aquarius, measure the emissivity of
the ocean. The emissivity of salt water is more sensitive to salinity in
warmer waters, and requires much more precise measurements and
calibration to retrieve a good estimate of the surface salinity in the
colder waters.”

ORP:  “Why do we study the water around Greenland?”

Anagh A:  “We need to study the water around Greenland because when ice sheets melt, they release freshwater into the ocean. This water changes the salinity and temperature of bodies of water around the planet, including oceans and seas. These changes in turn influence the ocean circulation of the planet in a process known as thermohaline circulation. Thermohaline circulation begins in the Earth’s Polar Regions when ocean water in these areas gets very cold, sea ice forms. The surrounding sea water gets saltier, increases in density and sinks. Surface water is pulled in to replace the sinking water, which in turn eventually becomes cold and salty enough to sink. This initiates the deep-ocean currents driving the global conveyer belt.”