The Whole Atmosphere Community Climate Model (WACCM) is a comprehensive numerical model, spanning the range of altitude from the Earth's surface to the thermosphere. The development of WACCM is an inter-divisional collaboration that unifies certain aspects of the upper atmospheric modeling of HAO, the middle atmosphere modeling of ACOM, and the tropospheric modeling of CGD, using the NCAR Community Earth System Model (CESM) as a common numerical framework.  The latest version of WACCM is described in Marsh et al. (2013)WACCM-X extends WACCM to the upper thermosphere, and includes processes important to the ionosphere.

Announcements and support for running WACCM can be found on the DiscussCESM WACCM forum.  The CESM Whole Atmosphere Working Group webpage can be found at

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WACCM Chemical Forecasts

CESM2/WACCM is now being run in real-time, driven by meteorological forecasts from NASA/GMAO GEOS-5. More details are provided on the Chemical Forecasts page. This document gives the full list of species being simulated in the WACCM forecasts.


See also: WACCM scientific publications by UCAR staff.




ACOM | Atmospheric Chemistry Observations & Modeling