Ocean bathymetry

Load Bathymetry; range[-11000 to 9000] m from Bathymetry.kmz or the combined

Ocean_Systems_MOOC.kmz file. In this overlay, bathymetry, or water depth, is presented with

depths ranging from -11km (dark blue) to +9km (white).

Where is the deepest point in the ocean? In which ocean is this found? What is the depth there?

Hint: Search for the Challenger Deep

Where is the deepest point in the Atlantic Ocean? What is the depth there?

Find the North Sea. In comparison how does the depth of this shelf sea compare with the average

of the ocean?

Sea Surface Temperature

Load SST_2013; range[-5 to 35] deg.C from SST_2013.kmz or the combined

Ocean_Systems_MOOC.kmz file. In this overlay, Sea Surface Temperature is presented with

temperatures ranging from < -5C (dark blue) to > +35C (dark red).

What is the typical distribution for the SST?

Does the distribution of SST remain, on average, the same throughout the year?

Sea Surface Salinity

Load SSS_2013; range[1025 to 1040] PSU from SSS_2013.kmz or the combined

Ocean_Systems_MOOC.kmz file. In this overlay, Sea Surface Salinity is presented with salinities

ranging from 25 Practical Salinity Units (PSU; dark blue) to 40 PSU (dark red).

What is the typical distribution for the SSS?

Give a reason why the most saline water is NOT found at the Equator despite typically higher

evaporation rates in this region.

Over the year, a distinct plume of low salinity can be seen from the north coast of the South

American continent. What do you think is the cause?

Hint: What do you think the effect of river run-off has on the oceans?

Sea Surface Atmospheric Pressure and Winds

Load Winds_2013; range[0 to 35] m/s from Winds_2013.kmz or the combined

Ocean_Systems_MOOC.kmz file. Next load Sea_Surface_Atmospheric_Pressure_2013; range[940 to

1060] hPa from Sea_Surface_Atmospheric_Pressure_2013.kmz or the combined

Ocean_Systems_MOOC.kmz file so that the pressure contours are imposed over the wind fields. In

these overlays, contours of atmospheric pressure at the sea surface between 960 and 1060 hPa are

presented along with blended wind fields providing the wind velocity between 0 (dark blue) and >35

(dark red) m/s.

In which direction are the predominant winds at the Equator? Using your knowledge of the SST

distribution and coriolis, can you explain this?

Move the time slider to the 28th December 2013. Over the UK, a region of low pressure is depicted

by the isobars. Can you explain the resulting wind direction?

What effect do you think this may have on the European weather?

Have a look at the wind patterns over the Southern Atlantic Ocean. What would you expect the

rotation sense of the South Atlantic Gyre to be?

Ocean Surface Currents

Load Ocean_Surface_Currents_2013; range[0 to 1] m/s from Ocean_Surface_Currents_2013.kmz

or the combined Ocean_Systems_MOOC.kmz file. Next load Ocean_Currents_Labels from

Ocean_Currents_Labels.kmz or the combined Ocean_Systems_MOOC.kmz file. In this overlay, the

ocean surface currents are presented with velocities ranging from 0 m/s (dark blue) to >1 m/s (dark

red). The names of a number of major ocean surface currents are given in the

Ocean_Currents_Labels overlay.

What is the rotation sense of the South Atlantic Gyre? Can you explain this from the predominant

wind patterns over the Southern Atlantic Ocean?

What is characteristic of the western boundary currents?

Can you name 3 western boundary currents?

Which ocean surface current encircles the entire globe?

Gulf Stream

Load Gulf_Stream_030106-080825; range[0 to 1] m/s from Gulf_Stream_030106-080825.kmz or

the separate Ocean_Systems_MOOC.kmz file. In this overlay, the Gulf Stream current is presented

with velocities ranging from 0 m/s (dark blue) to > 1 m/s (dark red).

Eddies or rings are shown to be shed from the main current. What is the typical size and duration

of these features?

Hint: One degree of latitude is approximately 110 km.

In the Northern Hemisphere, cold-core eddies i.e., eddies characterised with a lower temperature

in the centre have a counter-clockwise sense of rotation. Conversely, warm-core eddies, with a

warmer centre, have a clockwise sense of rotation. Identify the eddies shed from the north and

from the south of the main current.

The Gulf Stream can be considered to be barrier between the warm water towards the south and

the cold water in the north (review the SST overlay). What role do you think these eddies play in

transporting heat?

What effect do these eddies have for ecology and biological productivity?

Hint: Cold water, typically upwelled from depth, are typically nutrient rich.