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 # Cloud-J
 
+[![Ubuntu](https://github.com/geoschem/Cloud-J/actions/workflows/ubuntu.yml/badge.svg)](https://github.com/geoschem/Cloud-J/actions/workflows/ubuntu.yml)
+
 Cloud-J is a multi-scattering eight-stream radiative transfer model for solar radiation based on Fast-J. It was originally developed by Michael J. Prather (UCI). For information about the origins and history of Cloud-J and its predecessor Fast-J please see the [history document](https://github.com/geoschem/cloud-j/blob/main/docs/History_of_Fast-J_photolysis_code.md) in the docs subdirectory of this repository.
 
 ## How to build and run Cloud-J standalone