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Flashcards in Lecture 6 Deck (27)
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1
Q

Explain the earths energy budget

A

Energy surplus at low latitudes are equal to energy deficits at high latitudes = balanced heat budget.

As the heat is then transferred from the equator regions to the polar through wind and ocean currents.

2
Q

What drives ocean circulation?

A

Temperature
Salinity
(Cool, salty water = most dense)

3
Q

Explain thermohaline circulation

A

Warm water = lower density than cold
Cold regions - cold salty water sinks (heavy)
Evaporation increases salinity of water in warm regions
During journey to cold regions, salty water cools and sinks toward ocean floor
In contrast, diffuse upwelling occurs in warm regions
Therefore, temperature and salinity gradients drive an overturning circulation

4
Q

The North Atlantic current is responsible for…

A

The relatively mild climates of Western and Northern Europe

5
Q

What forms over the Gulf Stream?

A

Clouds, as water vapour evaporates from the ocean surface

6
Q

What probe is dropped 3500m and produces low frequency tones once a day for tracking currents?

A

SOFAR

7
Q

An example of meridonal overturning circulation:

A

Atlantic.

Being denser, Antarctic bottom water slips beneath North Atlantic deep water. The water then gradually rises across a very large area in the tropical zones, then flows poleward to repeat the cycle

8
Q

Water salinity is affected by:

A

Precipitation, run off, melting of ice + snow (decrease)
Evaporation (increase)
Input of dissolved ions is balanced by removal to sediments - global oceans in steady state

9
Q

Seawater solution =

A

Dissolved salts
Dissolved gases
Dissolved organic material
Large range of particles in suspension

10
Q

Meridonal overturning circulation is part of thermohaline circulation which can be called the:

A

‘Ocean conveyor belt’

11
Q

Thermohaline circulation

A

Driven by temperature and salinity

Contributes to the global distribution of energy in heat form

12
Q

El Niño southern oscillation

A

Abnormal weather pattern - caused by the warming of the Pacific Ocean near the equator.
Occurs when the normal trade winds weaken (or even reverse), which lets the warm water that is usually found in the western Pacific flow instead towards the east.
This warm water displaces the cooler water that is normally found near the surface of the eastern Pacific, setting off atmospheric changes that affect weather patterns in many parts of the world.
Happens usually every 2-7 years
Has to be a 0.5 degrees c change to be considered an El Niño year

13
Q

The tropical Pacific Ocean and atmosphere act as…

A

A giant heat engine that converts solar energy to kinetic energy of winds

14
Q

Walker circulation (walker cell)

A

Normal: trade winds blow towards the west across tropical Pacific = pile up of warm water in W Pacific
cold-nutrient rich water, wells up in S. American coast - supports diverse marine ecosystems, dry climate conditions
High water temperatures = extensive convection near Indonesia
Forms convective loop (important part of Hadley cell)
= formation of a zonal gradient in water temperatures

15
Q

El Niño conditions

A

Trade winds relax in central and western Pacific
Consequently, thermocline in Eastern Pacific gets depressed, W. Pacific elevated
Warm surface water moves eastwards followed by rainfall
Causes change in atmospheric circulations affecting weather even at great distances from Pacific

16
Q

Example of effects from El Niño

A

Flooding in South America

Drought in Indonesia and Australia

17
Q

La Niña conditions

A

Unusually cold sea temperatures
Trade wins strong
Sometimes follows El Niño
Opposite to El Niño (hot phase) - El Niña = cold phase

18
Q

Anthropogenic activities increasing CO2

A
Emissions from transport 
Energy generation (e.g. Coal, oil) 
Industrial and domestic heating
Cement production 
Deforestation (land use change)
19
Q

Natural sources of atmospheric CO2

A

Volcanoes (1/150th compared to anthropogenic)
Combustion processes (e.g. Wildfire)
Respiration of aerobic organisms (animals, humans)

20
Q

The average incoming solar radiation exceeds the average annual outgoing infrared radiation, emitted by the earth, between what latitudes?

A

40 N and 35 S

21
Q

What does the CO2 concentration depend on in the ocean?

A

Depends on amount of Co2 in atmosphere and temperature of water

22
Q

As water temperature increases, it’s ability to dissolve co2…

A

Decreases

23
Q

How much did CO2 increase in the atmosphere from the pre-industrial stage?

A

It doubled, which meant the oceans co2 doubled also

24
Q

Global warming reduces the oceans ability to absorb co2 leaving more in the atmosphere this will cause…

A

Higher temperatures

25
Q

Colder areas of water temp generally represent regions of…

A

Net co2 uptake

Warmer water regions = positive sea-air flux

26
Q

What is ocean acidification?

A

Uptake of increased co2 reduces surface ocean PH values, which increases the acidity of ocean water

27
Q

Increase in ocean acidification affects:

A

Coral reefs (declining calcification)
Cold water corals
Ecosystems where aragonite is essential (shell building)
Temperature increase results in coral bleaching