Chemical Aeronomy in the Mesosphere and Ozone in the Stratosphere (CHAMOS) is an on-going science collaboration focusing on energetic particle precipitation and related atmospheric effects. Originally, it was started by scientist from Finnish Meteorological Institute (FMI) and Sodankylä Geophysical Observatory (SGO) back in 1998 as an response to European Space Agency's Announcement of Opportunity related to the Global Ozone Monitoring by Occultation of Stars (GOMOS) instrument on board the Envisat satellite.
The collaboration has now continued for 20 years and produced over 100 peer-reviewed scientific publications. Today there are 30 people in the CHAMOS group, and more institutes have joined CHAMOS.
Over the years, CHAMOS work has been funded by Academy of Finland, European Union, New Zealand Marsden Fund, National Environmental Research Council (UK), University of Oulu (FI), Norwegian Research Council, and Japan Society for Promotion Science.