Capabilities implications and limitations of modelling

Capabilities, implications and limitations of modelling results

COMMENT: At the coldest time in the Mesozoic, there were perhaps small permanent ice caps on the poles. During the warmest time of the Mesozoic, there were unlikely to be freezing temperatures at the poles at all. These are examples of dramatic changes in climate brought on by changes in the Earth system. Why did these changes occur? What instigated cold poles vs. warm poles?

Numerical modeling is a tool that is used to help identify WHY and HOW these types of changes in the climate can occur. Lesson 15 introduces you to this tool by describing how modelling is applied to help understand the influence of various factors on Mesozoic global climate. Results of these efforts are summarized in this figure, to which the first 4 questions refer.

Concluding Comments

We base our understanding of Mesozoic climate and how it changed between 250 and 65 Ma on (a) observations from the rock, fossil and geochemical record and (b) models that incorporate the physics of global atmospheric and ocean dynamics. Of course there are still gaps in our knowledge and details in the observed fossil, rock or geochemical record that are not so well understood. You might find it useful or interesting to consider finding in Lesson 15 simple answers to the following questions:

What is at least one setting or location in the Mesozoic Earth from which would we like more fossils or other proxy information?
What are two examples of paleoclimate proxies for which we would like a more complete understanding of exactly how the observable information can be associated with ancient climatic conditions.
What aspects of those two proxies are scientists still working on improving?
What are two improvements to modelling that would enhance the likelihood of accurate outputs?

With initial modelling efforts, scientists attempted to calculate simulated global temperatures so that they would fall between which two curves?
1. A and E
2. A and C
3. B and D
4. B and E
5. C and D
6. D and E
After adjusting only geographic parameters, the best curve that could be produced was something like curve
1. A
2. B
3. C
4. D
5. E
After incorporating CO2, the best curve that could be produced was something like curve
1. A
2. B
3. C
4. D
5. E
After incorporating ocean heat transport, the best curve that could be produced was something like curve
1. A
2. B
3. C
4. D
5. E
In spite of getting temperature as a function of latitude to agree roughly with proxy data, what aspect of global temperature distribution was the model still not able to match very well with observations?
1. Equatorial temperatures over land and sea
2. Temperatures ranges in the interior of continents
3. Polar temperatures in all seasons
4. Minimum and maximum equatorial and polar temperatures
5. Temperature ranges in the northern and southern hemispheres
Compare the map of annual precipitation predicted by the model and the six paleoclimate and proxy maps for the Mesozoic. With which period of the Mesozoic is the modelled precipitation most consistent? Two possibilities are OK.
1. Lower Triassic
2. Upper Triassic.
3. Lower Jurassic
4. Upper Jurassic
5. Lower Cretaceous
6. Upper Cretaceous
If increasing the grid size of the model results in higher spatial resolution of the model output, why wasn't this model run with realistic coastline? (What are the logistical limitations of the model?)
1. the cost or time for calculations increases dramatically with smaller grid cells (increased grid size).
2. it might violate assumptions about relative amounts of ocean and landmass
3. not enough is known about coastlines in the Mesozoic
4. results would not be expected to be much different
5. it is lower spatial resolution that is actually wanted