We have saved CAM-chem simulation output that is intended to be used as boundary conditions for regional modeling. We used CAM-chem at 0.9x1.25 horizontal resolution simulation with 56 vertical levels. Meteorology is driven by specified dynamics, by nudging with 50h relaxation (1%) to MERRA2 reanalysis. Data is saved as instantaneous fields every 6 hours. See a list of saved species. Chemistry is the MOZART-T1 mechanism, described in Emmons et al. (2019). You can find a description of all simulated species online. We use the MAM4-VBS scheme to model aerosols. Files are collected as daily information (4 time-slices per file). Anthropogenic emissions are from CMIP6, CMIP6 2014 anthropogenic emissions are repeated for dates past 2014 to 2016. Anthropogenic and "other" emissions are changed to SSP5-85 for 2017 onwards. Biogenic emissions are from online MEGAN2.1, fire emissions are from QFED CO2 x FINN emission ratios (from 2015), with emission ratios updated from 2017 onwards. Note that fire emitted DMS 2001-2015 is from CMIP6, in 2016 from GFAS and 2017 onwards from QFED. SST in 2019 are repeated from 2018.
- Data Format: netCDF
- File size: 4.8 GB per day (4 x 6-hour instantaneous time slices per day)
- Data coverage: January 1, 2001 to December 31, 2018
*** NOTE: This version of output has incorrect HCN and O3S, please do not use these species ***
Get the data
1. Subset from dates within the time period January 1, 2001 to June 30, 2019
A small subset of the boundary conditions are available via rapid access from the ACOM server:
Regional and temporal subsetting option can be found at: https://www.acom.ucar.edu/cam-chem/cam-chem.shtml. Note there is a limit to download data in chunks of 32 days.
*** Boundary conditions usually lag by approximately 6 months due to input file availability. Currently with COVID-19 the lag is longer. ***
2. All available dates January 1, 2001 to June 30, 2019
To access any of the complete dataset of shared files between January 2001 and December 2018 you will need a Globus account, which requires a Google account. Get Globus access here.
Once you can log into Globus, the boundary conditions are stored here:
January 2001 to June 2017: https://app.globus.org/file-manager?origin_id=2acef47e-ed07-11e8-8cae-0a1d4c5c824a&origin_path=%2F
January 2017 to December 2018: https://app.globus.org/file-manager?origin_id=a0e862f4-772b-11e9-bf47-0e4a062367b8&origin_path=%2F
Files can be transferred to another location using the Globus system. To set up a transfer point see the relevant page:
Note: direct download option from this site is in beta testing phase and should be available in the future.
To cite the data directly, please use:
We suggest to also cite the following paper that discusses the new configuration of CESM2/CAM-chem and assesses chemical species, including using output from this boundary condition simulation.
Directions to access other experimental output can be found here: Benchmarks and Production
Using the boundary conditions with WRF-Chem
The CAM-chem chemistry and aerosols for this run are identical to the WACCM forecasts. Mapping CAM-chem output to WRF-Chem chemistry schemes can be found in:
which is linked from this page: