Thank you for your detailed and careful review of our manuscript!  In the revised manuscript, we have corrected the model to address the previous deficiencies in the biological weighting functions and the penetration of UV radiation.  We include a detailed response to your comments in the attached PDF. The full revised manuscript will be made available following the end of the discussion period.

Below is a summary of changes that will be made or have already been made in response to the suggestions:

The revised model now includes three times higher spectral resolution of E*inh attenuation with depth in the ocean column. A new updated attenuation scheme has been developed that is more appropriate for open ocean conditions. The biological weighting functions models that relate E*inh to phytoplankton damage now matches the original models used to construct the functions. The biological weighting function for small phytoplankton and diazotrophs has been changed from Prochlorococcus from Neale et al. (2017) to Synechococcus from Neale et al. (2014).  The PIC/POC scaling for coccolithophores has been adjusted down from 3.5 to 1.75 to account for potential PAR inhibition effects.

Dear Chief Editor,

We have archived the github repository of CESM2-UVphyto code onto Zenodo with a new identifier: 10.5281/zenodo.14025743 .

The previous version of code to create the figures has been moved into this archive as well with a new LICENSE.txt file including a GNU General Public License v3.0. All simulation data is still included in the previous archive with the identifier DOI: 10.5281/zenodo.11127431.

An updated version of the Code and Data Availability section reads as follows:

The code modifications to the CESM and Jupyter notebook entitled manuscript_figures.ipynb to generate all figures are stored on Zenodo at DOI: 10.5281/zenodo.14025743. The data used to produce figures in the main text and supplemental is archived on Zenodo at DOI: 10.5281/zenodo.11127431.

Sincerely,

Joshua Coupe and co-authors

We thank the reviewer for their comments and suggestions. We include a detailed response to your comments in the attached PDF. The full revised manuscript will be made available following the end of the discussion period.

We are very grateful for your careful review of our manuscript. The manuscript has been revised in response to your review as well as the first reviewer. A summary of changes to the manuscript in response to both reviews is provided below.

The revised model now includes three times higher spectral resolution of E*inh attenuation with depth in the ocean column. A new updated attenuation scheme has been developed that is more appropriate for open ocean conditions. The biological weighting functions models that relate E*inh to phytoplankton damage now matches the original models used to construct the functions. The biological weighting function for small phytoplankton and diazotrophs has been changed from Prochlorococcus from Neale et al. (2017) to Synechococcus from Neale et al. (2014).  The PIC/POC scaling for coccolithophores has been adjusted down from 3.5 to 1.75 to account for potential PAR inhibition effects.

Additional information regarding the UV radiation environment in the pre-industrial model simulations, especially compared to the present day, has been added to the manuscript. Text has been modified so that it aligns with figures more often (example: Figure 5). An additional discussion section has been added to emphasize how future work and even observational studies could improve modelling efforts. The methods section has been updated to make it clear how the bounds for lambda are defined. 

The full revised manuscript will be made available following the end of the discussion period.