DOI: 10.5061/dryad.3j9kd51r4
title: Data to support: Implications of snowpack reactive bromine production for Arctic ice core bromine preservation

description: Snowpack emissions are recognized as an important source of gas-phase
 reactive bromine in the Arctic and are necessary to explain ozone
 depletion events in spring caused by the catalytic destruction of ozone by
 halogen radicals. Quantifying bromine emissions from snowpack is essential
 for interpretation of ice-core bromine. We present ice-core bromine
 records since the pre-industrial (1750 CE) from six Arctic locations and
 examine potential post-depositional loss of snowpack bromine using a
 global chemical transport model. Trend analysis of the ice-core records
 shows that only the high-latitude coastal Akademii Nauk ice core from the
 Russian Arctic preserves significant trends since pre-industrial times
 that are consistent with trends in sea ice extent and anthropogenic
 emissions from source regions. Model simulations suggest that recycling of
 reactive bromine on the snow skin layer (top 1mm) results in 9–17% loss of
 deposited bromine across all six ice-core locations. Reactive bromine
 production from below the snow skin layer and within the snow photic zone
 is potentially more important, but the magnitude of this source is
 uncertain. Model simulations suggest that the Akademii Nauk core is most
 likely to preserve an atmospheric signal compared to five Greenland ice
 cores due to its high latitude location combined with a relatively high
 snow accumulation rate. Understanding the sources and amount of
 photochemically reactive snow bromide in the snow photic zone throughout
 the sunlit period in the high Arctic is essential for interpreting
 ice-core bromine, and warrants further lab studies and field observations
 at inland locations.
description: # Data to support "Implications of Snowpack Reactive Bromine
 Production for Arctic Ice Core Bromine Preservation"
 [https://doi.org/10.5061/dryad.3j9kd51r4](https://doi.org/10.5061/dryad.3j9kd51r4) This data set contains modeling output to support the Article "Implications of Snowpack Reactive Bromine Production for Arctic Ice Core Bromine Preservation". ## Description of the data and file structure The dataset contains results from each of 4 GEOS-Chem model simulations: mToyota, SURF, DEEP and DEEP2008. Please refer to the article for detailed description of the simulation setup. Each model simulation contains 28 data files (all model outputs are monthly averaged values): 1. **HEMCO\_diagnostics.YYYYMMDD0000.nc**: Emission fluxes, 1 file for each month, 12 files in total 2. **dryflx.YYYYMMDD.nc** : dry deposition fluxes, 1 file for every 3 months, 4 files in total 3. 3 and 4. **wetdcv.YYYYMMDD.nc** and **wetdls.YYYYMMDD.nc**: wet deposition fluxes, readers need to add these two together for the total wet deposition flux. 1 of each file (wetdcv and wetdls) for every 3 months, 8 files in total 4. **conc.YYYYMMDD.nc**: concentration files, 1 file for every 3 months, 4 files in total ## Sharing/Access information GEOS-Chem is open software and available on https://doi.org/10.5281/zenodo.5047976. We used the version 11-02d. ## Code/Software Example python code (in jupyter notebook) to generate figures presented in the Article is also available: **SnowBrPaper\_Fig.ModelResults.ipynb**