Climates of the past; Oceanography

Question 1

Define the albedo effect

Answer 1

A measure of how much of the sun’s energy is reflected off an object back out to space compared to how much is trapped in Earth’s atmosphere

Question 2

What drives the energy transfer and motion of the atmosphere and the ocean?

Answer 2

Heating imbalances in the oceans

Question 3

How are surface waters moved?

Answer 3

By winds that blow in certain patterns because of the earth’s spin and the Coriolis effect

Question 4

What is the Coriolis effect?

Answer 4

the pattern of deflection taken by objects not firmly connected to the ground, deflect to the right in the N hemisphere and to the left in the S hemisphere

Question 5

What is an ocean gyre?

Answer 5

large system of circular ocean currents formed by global wind patterns and forces created by Earth’s rotation

Question 6

Where are seasonal thermoclines formed?

Answer 6

At much shallower depths

Question 7

Describe albedo

Answer 7

Albedo is a non-dimensional, unitless quantity that indicates how well a surface reflects solar energy. It has a value between 0 and 1.

Question 8

What is a thermocline?

Answer 8

A thermocline is the transition layer in a body of water in which temperature changes more rapidly with depth than in the layers above or below
In the ocean, the thermocline divides the upper mixed layer from the calm deep water below

Question 9

Describe a seasonal thermocline

Answer 9

formed at much shallower depths during the summer as a result of solar heating but destroyed by diminished isolation and increased surface turbulence in the winter

Question 10

How are ocean surface circulations created?

Answer 10

driven by wind as a result of friction

Question 11

What process is responsible for many large scale weather patterns?

Answer 11

The Coriolis effect

Question 12

What is the Ekman effect?

Answer 12

when wind blows over the ocean, (when this happens, energy is transferred from the wind to the surface layers)
+ The change in wind direction with increasing height above the ground, or change in ocean currents with depth, that is determined by the Coriolis force

Question 13

What is wind stress?

Answer 13

the frictional force of wind which acts on the ocean surface

Question 14

What is the Ekman transport?

Answer 14

total volume of water transported at right angles to the wind direction per second

Question 15

What is the Ekman layer?

Answer 15

• the upper layer of the ocean which is influenced by the wind

Question 16

what does the Ekman theory predict?

Answer 16

• surface currents will flow 45 degrees to the surface wind path
• flow will be reversed at 100m below the surface
• flow at depth will be considerably reduced in speed

Question 17

Where does coastal upwelling occur?

Answer 17

where Ekman transport moves surface waters away from the coast; surface waters are replaced by water that wells up from below.

Question 18

What is the subtropical gyre?

Answer 18

a ring like system of ocean currents rotating clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere caused by the Coriolis Effect.

Question 19

What is the gulf stream?

Answer 19

a western intensified current largely driven by wind stress and part of the thermohaline circulation

Question 20

How does the Gulf stream work?

Answer 20

• As warm water flows from the equator to the poles it cools and evaporation occurs, this increases the amount of salt.
• Low temperature and a high salt content means high density and the water sinks deep in the oceans.
• The cold, dense water also moves slowly
• Eventually, it gets pulled back to the surface and warms by “upwelling” and the circulation is complete.

Question 21

what is the thermohaline circulation also known as?

Answer 21

• the meridonial overturning circulation

Question 22

Describe the thermohaline circulation?

Answer 22

Deep-ocean currents driven by differences in the water’s density, which is controlled by temperature (thermo) and salinity (haline)

Question 23

How do the polar regions ocean water initiate the deep-ocean currents driving the global conveyer belt/ thermohaline circulation?

Answer 23

• The polar regions ocean water gets very cold, forming sea ice, surrounding seawater gets saltier,
• its density increases, and it starts to sink.
• 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.

Question 24

How does CO2 get in the surface waters?

Answer 24

By the exchange of CO2 with the atmosphere

Question 25

How are nutrients limited in the ocean’s surface waters?

Answer 25

• phytoplankton in surface waters use up nutrients and then die
• they sink into deep waters
• the decay and oxidation of sinking releases nutrient s back into the deep waters Not the surface

Question 26

How can nutrients in the oceans be distributed to surface waters?

Answer 26

• by the process of upwelling, which is driven by Ekman transport

Question 27

Name 2 highly productive biomes

Answer 27

• polar oceans and sea ice zones

Question 28

Why are polar oceans highly productive ?

Answer 28

The formation and melting of sea ice is driven by seasonal changes and solar heating

Question 29

What are diatoms?

Answer 29

• single celled plants responsible for most of the primary production in sea ice zones

Question 30

Describe the albedo and temperature feedback system

Answer 30

• climate warming
• less sea ice = lowers reflectivity
• more solar radiation absorbed by ocean
• ncreased warming