Cryosphere in the Climate System: OGGM project

Two small projects in groups of two:

• Warming up (start May 19): due date May, 26 23:59
• Water ressources (start May 26): due date June 16, 23:59

To be returned in the OLAT Project return box.

What is expected?

• for the warming up: a PDF with 1-2 pages max
• for the water resources paper: 2-3 pages max including references

Run the notebooks on http://classroom.oggm.org. No need to send me any code, just the PDFs.

Grading

I will grade the entire notebook according to the following criteria:

• quality / clarity of the answers
• originality
• bonus points for typos / suggestions / etc. on the OGGM-Edu notebooks to be submitted to https://github.com/OGGM/oggm-edu-notebooks/issues

Warming up

01 - Glacier flow

Run the OGGM-Edu notebooks and understand their content:

• Getting started with the Jupyter Notebook if you are new to notebooks
• Getting started with OGGM Edu: idealised glaciers. Then, have a quick look at the OGGM-Edu API documentation: https://edu.oggm.org/en/latest/api.html
• Influence of ice flow parameters on glacier size

To better understand what the model is doing, have a look at the OGGM documentation:

• https://docs.oggm.org/en/stable/ice-dynamics.html

01-01

Explain what "a glacier in equilibrium" means, in at least two different ways (considering geometry, and considering mass balance).

When a single width, flat glacier is at equilibrium:

• where do you expect ice thickness to be maximal, and why?
• where do you expect ice velocity to be maximal, and why?

01-02

Repeat the Glen A (creep) parameter experiment here, with three glaciers in the collection and a creep parameter of 1 / 10 x default, default, x 10 default. Run all glaciers until the year 700 an plot the glacier geometries and the timeseries. Now answer the following questions:

• explain why the blue glacier (high creep) length changes faster than the other glaciers but stabilizes quicker.
• explain why the glacier attributes (volume, area, length) are increasing with decreasing creep and name the feedback responsible for this increase.

02 - Glacier advance and retreat

Run the following OGGM-Edu notebooks:

• Glacier advance and retreat
• Mass balance gradients and their influence on glacier flow

02-02

Realize a simple experiment with two plain flat glaciers and an ELA of 3000m and a gradient of 4. Let them run to equilibrium (the two glaciers should be strictly the same). Now change one ELA to 3200 m, the other to 2800 m. Let the glaciers run for an additional 80 years (should be age 600). Plot them. Now answer the following questions:

• explain the differences in the shape of the tongue (terminus) of an advancing and retreating glacier.
• hypothesize what it would mean for observations of ice velocity on glaciers in a changing climate.

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