Wednesday, 14 January 2004
Interannual variability of North America summer precipitation in CAM2.0 and NSIPP AMIP-like simulations
Hall 4AB
Interannual variability of summer precipitation and
moisture fluxes over North America from AMIP simulations
of two state-of-the-art models are compared, the
Community Atmosphere Model (CAM2.0), and the NASA
Seasonal-to-Interannual Prediction Project (NSIPP)
Model. The retrospective U.S. and Mexico precipitation
data set, and the NCEP reanalysis are used as targets of
the simulations for the 1950-1998 period. The analysis
suggests that notable summer precipitation anomalies
over the Great Plains are linked to anomalous vertically
integrated stationary moisture fluxes from the Gulf of
Mexico. AMIP simulations from the models produce
significant precipitation anomalies in the Central U.S.
but are unable to capture the southerly stationary
moisture fluxes from the Gulf of Mexico associated with
those events as seen in observations. It is suggested
that the moisture transport by transient motions is more
active in those models than observations indicate, but
that is currently under investigation.
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