Scripts used for the analyses of Wharton et al. (2024), Deeper and Stronger North Atlantic Gyre During the Last Glacial Maximum, Nature.

These scripts are used to produce the figures in Wharton et al. (2024) - Deeper and Stronger North Atlantic Gyre During the Last Glacial Maximum, Nature.

Note: All model outputs are located in the compressed file data.zip, with one output per model per variable in the directory "data" after decompressing.

All outputs were pre-processed using CDO commands, with all being at least 100-year long averages when possible, and some being meridional averages over the Atlantic Ocean. Outputs were all re-gridded onto a similar grid, the one of the model CESM1.2 (320x384)

script_fig_4.py - calculate wind stress curl from a POP2 function (https://pop-tools.readthedocs.io/en/latest/examples/pop_div_curl_xr_xgcm_metrics_compare.html) in PMIP4 models, multi-model average. The function will then calculate the average wind stress curl for both pre-industrial (PI) and Last Glacial Maximum (LGM) in the coordinates given, and build histogram of averages, including multi-model mean.

script_fig_7_toppanel.py - similar as script above but this time will generate individual maps for each PMIP4 models given.

script_fig_8_bottompanel.py - similar as script_fig_4.py but for PMIP3 models.

script_fig_9.py - show meridionally averaged potential densities in the northern Atlantic Ocean for some available models for both PI and LGM.

script_fig_10.py - similar as above but for ocean meridional velocities and difference between PI and LGM.

Spline_LGM.ipynb - script to fit a spline through LGM data, the latter of which is included in the script (Fig. 2b)

Spline_MH.ipynb - same as above, but for the Mid-Holocene data (Fig. 2a)

LGM_BOR_changepoint.ipynb - script to determine change point in new LGM Blake Outer Ridge data plus published data (Fig 2b). Uses .csv file ‘transect_data_LGM.csv’, which is also included in this repository.

MH_BOR_changepoint.ipynb - script to determine change point in new MH Blake Outer Ridge data plus published data (Fig. 2a). Uses .csv file ‘transect_data_MH.csv’, which is also included in this repository.