The Big Brother Experiment and seasonal predictability in the NCEP regional spectral model

摘要: The Big Brother Experiment methodology of Denis et al. (Clim Dyn 18:627-646, 2002) is applied to test the downscaling ability a one-way nested regional climate model. This consists first obtaining reference by performing large domain, high resolution model simulation—the Brother. small scales are then filtered out from Brother’s output produce data set whose effective comparable those sets typically used drive models. same model, integrated over smaller but at as - Little Any differences can only be attributed either errors associated with nesting strategy and technique, or inherent unpredictability system, not errors. was National Center for Environmental Prediction Regional Spectral Model tropical domain 1-month simulation period. reproduced most fields quite well, important exception small-scale component precipitation field, which poorly reproduced. Sensitivity experiments indicated that poor agreement these in due primarily behavior convective processes, specific on domain. Much better obtained an extratropical winter case, suggesting one factor explaining result importance processes controlling precipitation, versus greater large-scale dynamics extratropics. In results two ensembles five 3-month seasonal simulations forced GCM suggest considerably predictability stationary than did Experiment.