Comment On 'Using 226Ra And 228Ra Isotopes To Distinguish Water Mass Distribution In The Canadian Arctic Archipelago'.pdf

## Summary of Interactive Comment on "Using 226Ra and 228Ra isotopes to distinguish water mass distribution in the Canadian Arctic Archipelago"

This comment provides a detailed evaluation of Chantal Mears et al.'s study, which utilizes 226Ra and 228Ra isotopes to trace water mass distribution and circulation within the Canadian Arctic Archipelago. The reviewer generally agrees with the paper's findings and methodology but offers several suggestions for improvement.

Strengths:

Comprehensive dataset: The authors present a robust dataset spanning diverse locations in the study area, providing valuable insights into the complex oceanography of the Canadian Arctic.
Multi-parameter approach: Incorporating multiple parameters (DIC, Ba, oxygen isotopes) alongside Ra isotopes strengthens the analysis and allows for a more nuanced understanding of water mass characteristics.
Clear conclusions: The paper effectively summarizes its findings and situates them within existing literature.

Areas for Improvement:

1. Clarity of Presentation: Some figures could be improved for clarity, particularly regarding the representation of results and their relationship to interpretations.
2. Quantitative Details: Adding more quantitative details in the implications section would enhance the manuscript's impact by providing concrete examples and estimates.
3. Uncertainty and Limitations: Addressing uncertainties associated with Ra isotope ratios, circulation history, and the extent of westward flow along the northern flank of Lancaster Sound would strengthen the study's rigor. Visual aids like dashed arrows could help communicate these limitations.
4. Contextualization: The manuscript could benefit from a stronger connection between its findings and potential implications for climate change impacts on Arctic oceanography. Exploring minimum time scales for water transport, temperature differences, and heat delivery patterns would add valuable context.
5. Visual Aids:

Consider using full CTD cast data instead of just sample points in figures to better illustrate water column structure.
Use distinct color palettes and symbols to enhance readability, especially in figures with overlapping data points.
Label all relevant features on maps (e.g., station locations, boundaries) for clarity.

Overall:

The manuscript represents a valuable contribution to Arctic oceanography, offering novel insights into water mass distribution and circulation using Ra isotopes. Implementing the suggested revisions will further strengthen its impact and scientific value.