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arbeitsgruppen:stochastische_parameterisierungen [2015/10/29 10:14] (aktuell) |
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+ | =====Stochastic Parametrization===== | ||
+ | |||
+ | **Using the Plant-Craig stochastic convective parameterization in an | ||
+ | ensemble forecast system** | ||
+ | |||
+ | We have implemented the Plant-Craig (PC) stochastic convection scheme | ||
+ | into the limited-area COSMO (Consortium | ||
+ | for Small-scale Modeling) model. We have run the model with initial | ||
+ | and boundary conditions provided | ||
+ | by selected members of the ECMWF Ensemble Prediction System (EPS). | ||
+ | This allows us to compare how much | ||
+ | ensemble spread is introduced to the ensemble by the stochastic scheme | ||
+ | relative to that already present. | ||
+ | A stochastic parameterization, like the PC-scheme, takes into account | ||
+ | the fact that the intensity of unresolved | ||
+ | convection is not merely determined by resolved-scale parameters, but | ||
+ | also by unresolved physics. To this | ||
+ | aim, the PC-scheme, being based on statistical physics, uses | ||
+ | convective plumes that are randomly drawn from a | ||
+ | probability density function that describe the chance of launching a | ||
+ | plume with a certain mass flux each time the | ||
+ | scheme is called. | ||
+ | |||
+ | ---- | ||