Title: Indirect effects of secondary organic aerosol on cirrus clouds
Authors: Jialei Zhu, Joyce E. Penner
Contact: Jialei Zhu, jialeiz@umich.edu

Key Points:
- A new version of the CESM/IMPACT atmospheric model was developed to include the effect of secondary organic aerosol on cirrus clouds.
- The effect of secondary organic aerosols on cirrus clouds using two treatments were simulated. 
-The forcing of aircraft soot on cirrus clouds when including secondary organic aerosols was simulated.


Research Overview:
Secondary organic aerosols (SOA) have been identified as the efficient ice nucleating particles and thus have a radiative effect on cirrus clouds. This study develops a global model to exam the radiative effect of SOA in cirrus clouds using different treatments. The SOA formed from organic particle nucleation has a radiative effect of 0.35 W m-2, while the radiative effect of SOA calculated by assuming a fixed size distribution is 0.31W m-2.  SOA has a positive radiative effect on cirrus clouds whereas the effect of anthropogenic soot is negative. In addition, SOA changes the background ice number concentration which impacts the calculation of radiative forcing from other aerosols. The radiative forcing of aircraft soot is estimated to be -0.11~-0.16 W m-2 depending on which SOA treatment is used. This is less negative than that in a previous study that did not include ice nucleation from SOA. 

Methodology:
The data are model output for the radiative effect of secondary organic aerosol on cirrus clouds simulations conducted using the Community Earth System Model (CESM) version 1.2.2.1 coupled with the IMPACT aerosol module. The input files are default in the component set of “FC5” in CESM model for all cases.

Files contained here:
We include five source code tar files and 60 major output netcdf files from simulations conducted in the paper. The ending of 1-12 stand for the 6-year average in each month from January to December. “dbfc” stands for the base case with the emission of dust, biomass burning, fossil fuel burning and aircraft soot. “dbfcs_fix” stands for the base case adding SOA calculated by assuming a fixed size distribution. “dbfcs_new” stands for the base case adding SOA formed from organic particle nucleation. “dbfs_fix” is same with “dbfcs_fix” but without emission of aircraft soot. “dbfs_new” is same with “dbfcs_new” but without emission of aircraft soot.

The files are described below:

dbfc.zip
This tar file contains the source code of the IMPACT aerosol module that we implemented as additional aerosol module embedded in the CESM version1.2.2.1 which is publicly available from NCAR repository. This code is for the base case applied in the related publication.

dbfcs_fix.zip
This tar file contains the source code of the IMPACT aerosol module that we implemented as additional aerosol module embedded in the CESM version1.2.2.1 which is publicly available from NCAR repository. This code is for the case “dbfcs_fix”applied in the related publication.

dbfcs_new.zip
This tar file contains the source code of the IMPACT aerosol module that we implemented as additional aerosol module embedded in the CESM version1.2.2.1 which is publicly available from NCAR repository. This code is for the case “dbfcs_new”applied in the related publication.

dbfs_fix.zip
This tar file contains the source code of the IMPACT aerosol module that we implemented as additional aerosol module embedded in the CESM version1.2.2.1 which is publicly available from NCAR repository. This code is for the case “dbfs_fix”applied in the related publication.

dbfs_new.zip
This tar file contains the source code of the IMPACT aerosol module that we implemented as additional aerosol module embedded in the CESM version1.2.2.1 which is publicly available from NCAR repository. This code is for the case “dbfs_new”applied in the related publication.

dfbc-6a-**.nc
Netcdf output file of 6-year mean monthly meteorological and aerosol fields from the base case. 

dfbcs_fix-6a-**.nc
Netcdf output file of 6-year mean monthly meteorological and aerosol fields from the “dfbcs_fix” case. 
 
dfbcs_new-6a-**.nc
Netcdf output file of 6-year mean monthly meteorological and aerosol fields from the “dfbcs_new” case.

dfbs_fix-6a-**.nc
Netcdf output file of 6-year mean monthly meteorological and aerosol fields from the “dfbs_fix” case.
dfbs_new-6a-**.nc
Netcdf output file of 6-year mean monthly meteorological and aerosol fields from the “dfbs_new” case.


Related publication(s):
Zhu, J and Penner, J. E.: Indirect effects of secondary organic aerosol on cirrus clouds, (2019), submitted to Geophysical Research Letter.


Use and Access: 
This data set is made available under a Creative Commons Attribution-NonCommercial 4.0 International license(CC BY-NC 4.0).

To Cite Data: 
Zhu, J and Penner: Indirect effects of secondary organic aerosol on cirrus clouds, (2019)[Data set]. University of Michigan Deep Blue Data Repository. https://doi.org/10.7302/aqa1-5t49