WACCM

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 Gettelman et al. (2019). WACCM-X extends WACCM to the upper thermosphere, and includes processes important to the ionosphere.

Daily chemical forecasts are now being provided with the Whole Atmosphere Community Climate Model (WACCM) configuration of CESM2 [Gettelman et al., 2019, https://doi.org/10.1029/2019JD030943]. 10-day forecasts are being run, driven by NASA/GMAO GEOS-5 meteorological forecasts. Fire emissions are updated daily with near-real-time FINNv1 emissions and used for the following 10-day forecast. Anthropogenic emissions are from the CAMS inventory. The chemistry scheme is the MOZART TSMLT1 chemical mechanism [Emmons et al., 2020, https://doi.org/10.1029/2019MS001882] with MAM4 aerosols (see Liu et al. (GMD, 2015)).

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 http://www.cesm.ucar.edu/working_groups/Whole-Atmosphere/.

Subseasonal-to-seasonal forecasts of the Northern Hemisphere polar vortex are available every Monday.

Featured Research

• Linking terrestrial and space weather with high-resolution WACCM simulations
• Keying in on the atmosphere's vertical reverberations (from the NCAR annual report)
• WACCM Model Simulates Global Environmental Effects of a Regional Nuclear War
• Stratospheric sulfates have human cause
• WACCM Model Simulates the Antarctic Ozone Hole
• Importance of very short-lived halogens for understanding the response of surface UV to geo-engineering of climate
• Using WACCM to investigate the influence of stratospheric ozone loss on trends in sea ice
• Comparison of Antarctic ozone hole for 2018 and 2019 (YouTube).

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.

Carbon monoxide tracers

Tagged CO tracers are included in the WACCM forecasts (labeled CO01 to CO09) and are based on subsets of CO emissions:

• CO01: global biomass burning
• CO02: North America anthropogenic
• CO03: Europe
• CO04: Northern Africa
• CO05: Western Asia
• CO06: East Asia
• CO07: South America
• CO08: Southern Africa
• CO09: Australia

See also: WACCM scientific publications by UCAR staff.