bogeholm / ice-sheets-fluctuating-temp

MATLAB and Jupyter notebook files for ** ** "Influence of temperature fluctuations on equilibrium ice sheet volume"

We greatly acknowledge the work by the authors of the following papers upon which we build:

• Oerlemans, J. (2003), A quasi-analytical ice-sheet model for climate studies, Nonlinear Processes in Geophysics, 10(4/5), 441–452, doi: 10.5194/npg-10-441-2003.

• Robinson, A., R. Calov, and A. Ganopolski (2012), Multistability and critical thresholds of the Greenland ice sheet, Nature Climate Change, 2(6), 429–432, doi: 10.1038/nclimate1449.

• Fettweis, X., B. Franco, M. Tedesco, J. H. van Angelen, J. T. M. Lenaerts, M. R. van den Broeke, and H. Gallée (2013), Estimating Greenland ice sheet surface mass balance contribution to future sea level rise using the regional atmospheric climate model MAR, The Cryosphere, 7, 469–489, doi: 10.5194/tc-7-469-2013.

MATLAB scripts assume the following packages are installed:

• export_fig by Yair Altman

• ds2nfu by Michelle Hirsch

• hslcolormap by Aslak Grinsted

• suplabel by Ben Barrowes

• matrix2latex by Moritz Koehler

File descriptions

• data/ar1results.mat Contains AR(1)-coefficient and variance from fitting an AR(1)-model to annual Greenland reanalysis data. Created by greenlandTemperature.m.

• data/GreenlandTemperatureData.txt Contains monthly reanalysis data from climexp.knmi.nl (see the file for a description).

• greenlandTemperature.m: Loads Greenland temperature data and fits an AR(1) model. Calculates simple diagnostics on the model. This is done after loading GreenlandTemperatureData.txt. Saves results in data/ar1results.mat.

• icesheetsCrossterms.m Evaluates the contribution from the cross and volume variance terms in equation (3) in the article.

• icesheetsLongTerm.m Applies effect of fluctuating temperature to Robinson et al.'s results.

• icesheetsSetup.m Common script setup. Contains path and font size variables etc.

• icesheetsSimulations.m Integrates the Oerlemans (2003) model with fluctuating temperature.

• icesheetsStepsize.m Evaluates the consequences of the chosen integration time step size for the Oerlemans model.

• iceTotal.m Utility function to ease the use of iceVolume.m.

• iceVolume.m Calculates the ice sheet volume given the radii of the 1) ice sheet and 2) the continent upon which the ice sheet rests.

• MassBalanceSketch.ipynb Sketches the mass balance as a function of altitude for the Oerlemans (2003) model. Juyter notebook.

• oerlemansModel.m The Oerlemans (2003) model.

• oerlemansParam.m Contains parameters for the simulations.

• simnumber.m Convert from parameter values and warming value to simulation number in Robinson et al.'s (2012) data.

Workflow

1. Run greenlandTemperature.m to fit an AR(1) model to reanalysis data
2. Decide whether to comment/uncomment

• save_pdf and save_png to save figures

3. Decide whether to comment/uncomment

• thisrun = production or thisrun = test in icesheetsSimulations to save time

4. Run scripts to make figures and print out data

Figures in the article

• Figure 1: MassBalanceSketch.ipynb

• Figure 2: icesheetsSimulations.m

• Figure 3a: icesheetsSimulations.m

• Figure 3b: icesheetsLongTerm.m

• Figure 4: icesheetsLongTerm.m

Figures in the supplement

• Figure S1: icesheetsStepsize.m

• Figure S2: greenlandTemperature.m

• Figure S3: icesheetsCrossterms.m

• Figure S4: icesheetsLongTerm.m

• Figure S5: icesheetsLongTerm.m