Data supporting Nica, Anna et al. (2025) "Impact of Galactic Cosmic Rays on Earth's Climate During an Encounter with the Local Lynx Cold Clouds 2-3 Myr Ago"

<Version 1> Data from the GSFC 2D climate chemistry and dynamics model and implementation of version 3 of the CRAC:CRII model developed by Usoskin et al. (2024) supporting Nica, Anna et al. (2025) "Impact of Galactic Cosmic Rays on Earth’s Climate During an Encounter with the Local Lynx Cold Clouds 2-3 Myr Ago". For our implementation of version 3 of the CRAC:CRII model (Usoskin et al. 2024), we provide the Jupyter notebook CRAC3_Nica1.ipynb (in Python 3.8.8) which generates cosmic ray-induced ion pair production profiles dependent on heliospheric modulation, geomagnetic shielding, and geographic latitude. This Jupyter notebook implements functions from the file CRACin.py, which calculates the altitude profiles, and creates and writes to a file called 'F40GCRMM.DAT'. This file contains the GCR-induced ion pair production (in units ion pairs/cm3/s) at altitudes between 85 degrees South to 85 degrees North. Versions of this file for each case are contained in the following .zip files, and then passed into the GSFC 2D model: the solar minimum case (GCRions_phi325.zip) the LIS case, which includes atmospheric ionization from GCRs outside the heliosphere (GCRions_phi0.zip) the LIS-GM case, which includes GCRs from outside the heliosphere and removes geomagnetic shielding of cosmic rays (GCRions_phi0_noRc.zip) We run the GSFC 2D climate chemistry and dynamics model, which we have modified slightly to vary the input of ion pair production induced by GCRs based on our output from the CRAC:CRII model. The following zip files contain the ncl file output by the NASA GSFC 2D atmosphere model in three cases: the solar minimum case (CRAC3phi325_s.zip) the LIS case (CRAC3phi0_s.zip) the LIS-GM case (CRAC3phi0_noRc_s.zip) The Jupyter notebook plot_GSFC_specoutnc_Nica1.ipynb (in Python 3.11.5) plots the output of these runs. - <Version 2> This version adds the file Rc_plots.ipynb, which plots the geomagnetic cutoff rigidity for Earth's dipole magnetic field (using modern day conditions) and during a pole reversal.