Christopher L. Castro, Ph.D.
Assistant Professor
Department of Atmospheric Sciences
The University of Arizona

Use of Regional Atmospheric Modeling to Address Climate Variability and Change in Arizona

As the fastest growing U.S. state in an arid to semi-arid region, Arizona's sensitivity to natural climate variability and potential anthropogenic climate change is increasing.  There is an urgent societal need for climate projections at seasonal timescales and beyond, and the state of Arizona has deemed this a high research priority.  At present, the principle tools which are being relied upon to produce such forecasts are general circulation models (GCMs).  Owing to their parameterizations and course resolution, GCMs cannot resolve important physical mechanisms associated with precipitation in Arizona and may have marginal skill in representing long-term natural climate variability.  The problem is particularly acute during the summer because of the more localized and convective nature of precipitation.  In spite of these caveats, prominent GCM-based studies have made specific and dramatic claims about how Arizona climate may change in the future.  In this presentation, the use of regional atmospheric modeling in North America is proposed for climate projection. Regional models add value by better representation of physical processes on the local scale, such as convection during the monsoon.  It will be demonstrated that such value added by regional models is necessary to represent natural climate variability during the warm season and may also lead to surprising conclusions with respect to anthropogenic climate change. A strategy toward long-range climate projection in Arizona will be outlined, as this is the subject of my forthcoming research.

Please join us for refreshments at 10:45 a.m.