NCAR Summer
School, 13 August 2008
Regional Climate Models
Perturbed
physics ensemble
¥How much variability in RCM simulations
is due to settings of closure
parameters?
¥Parameters that control the behavior of
parameterizations.
¥Construct an ensemble in which each
member uses a different value for a closure parameter or
parameters:
¥Must truly be an adjustable parameter
(e.g., donÕt vary gravitational acceleration or specific heat).
¥Parameter value should be
reasonable.
¥Here: in the Grell scheme of RegCM2,
vary
Dp = lifting depth threshold
for triggert = time scale for release of convective instability