Part 1

For the first few questions you will have to look at the four different Figures (A-D) and determine to which hemisphere their pressure systems belong to. Remember that Pressure Gradient Force and the Coriolis Force work together: 

1. The atmospheric pressure system in Figure A below is located in the...:

a. Northern Hemisphere

b. Southern Hemisphere

2. Look at the black wind arrows in Figure B below. The atmospheric pressure system in Figure B is located in the...:

a. Northern Hemisphere

b. Southern Hemisphere 

3. The atmospheric pressure system in Figure C below is located in the...:

a. Northern Hemisphere

b. Southern Hemisphere 

4. The atmospheric pressure system in Figure D is located in the...:

a. Northern Hemisphere

b. Southern Hemisphere 

For the next four questions you need to look at pressure maps and determine the location of the strongest winds and it's wind direction. 

5. Look at the pressure map of Europe below. Which location has the highest winds?

a. Location A

b. Location B

c. Location C

d. Location D

6. Look at the location with the highest wind at the map of Europe below. Taking into account only the Pressure Gradient and the Coriolis Force, what is the wind direction at that location? 

a. From North to South

b. From South to North

c. From West to East

d. From East to West

e. From North West to South East

f. From North East to South West

g. From South East to North West

h. From South West to North East

7. Look at the pressure map of Australia below. Which location has the highest winds?

a. Location A

b. Location B

c. Location C

d. Location D

8. Look at the location with the highest wind at the map of Australia below. Taking into account only the Pressure Gradient and the Coriolis Force, what is the wind direction at that location? 

a. From North to South

b. From South to North

c. From West to East

d. From East to West

e. From North West to South East

f. From North East to South West

g. From South East to North West

h. From South West to North East

The next three questions in this part are about the linear velocity effect of the coriolis force. 

9. What does Newton’s 1st law imply for the apparent movement of an air mass which moves from the equator towards the North Pole? The movement appears to deflect towards:

a. North

b. East

c. South

d. West

10.  What does Newton’s 1st law imply for the apparent movement of an air mass which moves from the North Pole towards the equator?  The movement appears to deflect towards:

North

East

South

West

11. What does Newton’s 1st law imply for the apparent movement of an air mass which moves from the equator towards the South Pole? The movement appears to deflect towards:

a. North

b. East

c. South

d. West

The next two questions are about the angular velocity effect of the coriolis force:

12.  Imagine you are asleep at the North Pole, but teleported to a frictionless ice rink at the equator. What is you rotation relative to everything else around you? You would wake up apparently... 

a. ...spinning slowly counterclockwise on the ice.

b. ...spinning slowly clockwise on the ice.

c. ...standing still.

13. Imagine you are asleep at the equator, but teleported to a frictionless ice rink at the North Pole. What is you rotation relative to everything else around you? You would wake up apparently... 

a. ...spinning slowly counterclockwise on the ice.

b. ...spinning slowly clockwise on the ice.

c. ...standing still.

Part 2: Video - Is the Polar Vortex caused by Climate Change?

Watch the following youtube clip before you answer the following questions. It is a video made by Simon Clark, a scientist who wrote his PhD thesis about the polar vortex:

14. True or False: Is the Polar Vortex caused by Climate Change? 

15. Where in the atmosphere is the Polar Vortex located? 

a. Troposphere

b. Stratosphere

c. Mesosphere

d. Thermosphere

16. What is the Polar Vortex?

a. a large hurricane

b. an area of cold temperature

c. high winds

d. extreme weather event

17. When does the Polar Vortex form?

a. every summer

b. every winter

c. occasionally in summer

d. occasionally in winter

e. randomly throughout the year

18. How do you call the event, when the Polar Vortex splits apart?

a. Cold Wave

b. Blizzard

c. Sudden Stratospheric Warming

d. Sudden Stratospheric Freezing

19. Where in the atmosphere is the Polar Jet Stream located?

a. Troposphere

b. Stratosphere

c. Mesosphere

d. Thermosphere

20. What is the Polar Jet Stream?

a. Temperature gradient between lower and higher latitudes

b. strong winds travelling from lower latitudes to the Poles

c. strong winds travelling from the Poles to the mid-latitudes

d. strong winds circulating along the polar front (West to East).

e. strong winds circulating along the polar front (East to West).

21. How is the Polar Jet Stream effected by Sudden Stratospheric Warming?

a. weakening the jet-stream

b. strengthening the jet-stream

c. stopping the polar jet stream

d. no effect on the jet stream

22. What is Arctic Amplification?

1. 1. 1. Local cooling of the Arctic contrary to the global warming trend, 

      2. Warming in the Arctic, much faster relative to the global rate due to positive feedbacks in the Arctic climate system.

      3. Development of stronger winds around the Arctic due to amplifying mechanisms in the arctic climate system.

      4. Development of weaker winds around the Arctic due to amplifying mechanisms in the arctic climate system.

23.  How could Arctic Amplification affect the Polar Vortex?

1. 1. 1. Arctic Amplification weakens the temperature gradient between Poles and lower latitudes and therefore weakens the Polar Vortex.

      2. Arctic Amplification strengthens the temperature gradient between Poles and lower latitudes and therefore strengthens the Polar Vortex.

      3. Arctic Amplification weakens the temperature gradient between Poles and lower latitudes and therefore strengthens the Polar Vortex.

      4. Arctic Amplification strengthens the temperature gradient between Poles and lower latitudes and therefore weakens the Polar Vortex.

24.  True or False: Current Computer Models can confirm the linkage of Arctic Amplification on the Polar Vortex.

25.  What does Simon Clark conclude about the question if 'the recent cold snaps caused by the polar vortex dynamics occurred because of anthropogenic climate change'. 

1. 1. 1. Yes, it is fully caused by anthropogenic climate change.

      2. Yes, it is partly cuased by anthropogenic climate change.

      3. No, it is only natural variability.

26.  What does he base his conclusion on?

1. 1. 1. Computer model results.

      2. Processes in the atmosphere which makes the connection between Arctic Amplification and the Polar Vortex dynamics impossible.

      3. Observational data.

      4. All above.

Part 3: Carbonbrief - How is Arctic warming linked to the ‘polar vortex’ and other extreme weather?

Carbon Brief is a UK-based website covering the latest developments in climate science, climate policy and energy policy. The following article is also listed under your recomended readings because it covers a lot I talked about in the lecture (and more) in a good to understand language and provides good links to videos and further readings about the linkage of arctic warming and extreme weather events. I highly recommend to read the whole article but for this reading assignment we are intressted in the last three sections with the headings ‘What are the criticms of the theory?’, ‘Why is there uncertaintiy around the theory?’ and ‘Could a definitive link emerge in the future?’. 

Click on the following link and read those three sections before you answer the following questions: 

https://www.carbonbrief.org/qa-how-is-arctic-warming-linked-to-polar-vortext-other-extreme-weather

27. What is the differnce between ‘correlation’ and ‘causation’?

1. 1. 1. One action correlates with another which means there is always a causation. But just because two things are interacting with eachother does not mean there is a correlation, even it seems to make sense.

      2. One action causes another, which means they are correlated. But just because two things occur together does not mean that one caused the other, even if it seems to make sense.

      3. One action can cause another but not vice versa. The otherway round would be just a correlation.

      4. There is no differnce. Everything which correlates is caused by each other. 

28. Why is it tricky to show (or disproof) causality in the linkage of arctic warming and extreme weather events?

1. 1. 1. Arctic Amplification means that the Arctic gets warmer and therefore the winter extremes should get warmer and less extreme rather than colder and more extreme. What we saw in previous winters was just an exemption. There is no causality.

      2. We do not have long enough time series of related data to proof or disaproof our theories about the linkage.

      3. The theories we have make no sense.

29. What is the only way to show causality at the moment?

1. 1. 1. Replicate the linkage with climate models.

      2. Get more observational data.

      3. Make up our mind if we rather believe data or models.

30. What is believed to be the main reason for the disagreement on the linkage between arctic warming and extreme weather among climate scientists?

1. 1. 1. Climate Scientist needs to decide which one of the many theories is true.

      2. The theories we have are all purley hypothetical and are not based on our common understanding of the atmosphere.

      3. Observations are strongly suggestive of a causal link between arctic warming and extreme weather while models do not confirm this link.

31. What do Jennifer Francis and Judah Cohen believe could cause this disagreement?

1. 1. 1. Current models could underplay/miss some processes within the climate system and therefore can’t properly simulate or represent the ‘arctic warming/extreme weather event’-link.

      2. Observations are more trustworthy than computer model results.

      3. Computer model results are more trustworthy then observations.

      4. Scientist have the tendency to be biased to their own work and don’t accept the results of other scientist with different view.

Part 4: Essay by Jennifer A. Francis - Why are arctic linkages to extreme weather is still up in the air?

The following essay is written by one of the leading scientists in this field, who was one of the first who connected arctic amplification with extreme weather events in the mid-latitudes. 

 Click on the following link and read this essay before you answer the following questions: 

 J. Francis (2018): Why are arctic linkages to extreme weather is still up in the air?

32. According to Francis, how much sea ice has been lost over the last few decades?

About _____% of the volume.

33. ...and how much does the sea-ice decline account for Arctic Amplification.

As low as _____>#/em###

34. Fill in the Blank: Figure 1 of the essay shows four graphs, all with vertical axis representing pressure (hPa). 1000hPa is about the pressure at Earth’s surface, 300hPa is about the pressure at the height of the polar jet stream. The horizontal axis represent latitudes. Looking at the two top graphs (temperature change), you can see that both graphs show a __________(stronger/weaker) warming at high latitudes than at low latitudes. 

35. While the left top graph is a model result of a simulation with only sea-ice loss as an Arctic Amplification cause, the right top graph uses all known Arctic Amplification processes. Which of the two graphs show are stronger Arctic Amplification?

a. top left

b. top right

36. Arctic Amplification causes....

1. 1. 1. a stronger temperature gradient between high and low latitudes.

      2. a  weaker temperature gradient between high an low latitudes.

37. Fill in the Blanks: Consider Question 4:  Francis uses Figure 1 as an example to show how models which are missing crucial processes (in this case using only sea-ice loss) might _______________(underestimate/overestimate) the effect of Arctic Amplification on extreme weather, since a weaker temperatue gradient causes are __________(stronger/weaker) jet stream and therefore __________(increase/decrease) the likelyhood of extremer weather in the mid-latitudes.

38. Some models only simulate atmospheric processes in the troposphere. Why could this be a problem?

1. 1. 1. The solar radiation is affecting all levels of the atmosphere, looking at only the troposphere means missing a big amount of solar forcing. 

      2. The polar vortex develops in the stratosphere but can descend into the troposphere in winter. By ignoring the stratosphere, the models ignore a potential development of the Polar Vortex and its movement between the spheres.

      3. Those models miss the exchange of troposphere/stratosphere wave energy in both direction. Sea-ice loss can causes the tropospheric jet stream to weaken. This can eventually disturbe the stratospheric polar vortex, which later transfers the wave anomaly back to the troposphere. 

39. True or False: According to Francis, the atmospheric response to Arctic Amplification is highly dependent on spatial and temporal processes caused by regional forcing and seasonal mechanisms which usual climate models do not represent because of their low spatial and temporal resolution.

Part 5: You

40. After watching the video and reading the two articles, what is your conclusion? (no wrong answer here!)

1. 1. 1. The link between Arctic Amplification and Extreme Weather is down to natural variability and has nothing to do with human inforced climate change? Models would otherwise confirm the link.

      2. There is no way that Arctic Amplification is not influencing Atmospheric Dynamics. Models are still missing or underestimating crucial atmospheric processes. We just don’t know enough about those processes yet to get the models right.

      3. Undecided.