653 Sensitivity of Summer Convective Precipitation to Dynamical Core Configurations in the GEM Model

Tuesday, 14 January 2020
Hall B (Boston Convention and Exhibition Center)
Rabah Aider, Recherche en Prévision Numérique, Environment and Climate Change Canada, Dorval, Canada; and S. Gaudreault

Notable differences are found in the accumulated tropical summer convective precipitation (CP) produced by the Canadian Global Environmental (GEM) model when run with various configurations of the dynamical core.

Our goal in this study is to evaluate the sensitivity of the CP to some configurations of the dynamical core of GEM model. To this end,we have conducted simulations using identical physics schemes and parameterization but different configurations of the components of the dynamic core including elliptic solvers and the semi-Lagrangian scheme. The variations in the dynamical core settings considered here relate to purely numerical aspects and have no significant impact on the prognostic variables accuracy.

Objective skill scores are computed by comparing the model predictions against radiosonde observations and reanalyses.

Our study rises the question whether dynamical core configurations should be considered as part of probabilistic precipitation forecasts and ensemble prediction system design besides the perturbed physics and initial condition uncertainty.

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