Priorities

The development of WACCM is motivated by an appreciation of the importance of coupling between atmospheric regions. Vertical propagation of atmospheric waves and the transport of minor species from the troposphere are known to play major roles in the dynamics and chemistry of the middle and upper atmosphere. There is also increasing awareness that changes in the propagation characteristics of planetary waves in the stratosphere (due to natural or anthropogenic factors) may play a role in tropospheric climate variability by influencing such phenomena as the Arctic Oscillation.

Projected applications of the model for scientific studies include the following:

• Investigate interactions between stratospheric dynamics and chemistry to elucidate the role of natural and anthropogenic variability in ozone depletion during the last 20 years and into the 21^st century.
• Investigate the effects of solar variability on the middle and upper atmosphere on time scales ranging from the solar rotation period to the 11-year solar cycle.
• Study processes controlling the stratosphere/troposphere exchange of mass and minor constituents.
• Interpret observations from NASA satellites: Aura MLS, SAGE III/ISS, SABER, ACE-FTS and Odin OSIRIS.
• Investigate the effects of coupling between the stratosphere and the troposphere on climate variability.
• Understand whether stratospheric ozone and temperature changes induced by the 11-year solar cycle play a role in observed correlations between the solar cycle and tropospheric and lower stratospheric temperature and geopotential patterns.
• Study physical and chemical processes in the vicinity of the mesopause, in particular changes associated with increasing CO₂ concentrations.