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JSchwake28

Ensemble perturbations

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I never really thought about this before, but how are the initial condition adjustments set when running ensembles? Is it random? Which inputs are actually adjusted?

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I never really thought about this before, but how are the initial condition adjustments set when running ensembles? Is it random? Which inputs are actually adjusted?

I'll post the sref one tommorow if I have time. Different inital conditions within the SREF and it's not random. Would like to know more about the EC ensemble spread in terms of physics parameters and different inital conditions,

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I never really thought about this before, but how are the initial condition adjustments set when running ensembles? Is it random? Which inputs are actually adjusted?

 

There is a paper by Wei et al. 2007 that goes into detail about how initial conditions are perturbed in the GEFS. I have not read it.  As far as I know, its the same GFS core with all of the ensemble members, just a coarser resolution. The Canadian ensembles and the SREF members have different cores/physics packages in addition to perturbing the initial conditions within those cores. Mitch, especially with the SREF, is more up on this than I am.  I have read a comment that the ECMWF's cores are all the same, a complaint that its ensemble members just follow the leader too often. I cant substantiate this.

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There is a paper by Wei et al. 2007 that goes into detail about how initial conditions are perturbed in the GEFS. I have not read it.  As far as I know, its the same GFS core with all of the ensemble members, just a coarser resolution. The Canadian ensembles and the SREF members have different cores/physics packages in addition to perturbing the initial conditions within those cores. Mitch, especially with the SREF, is more up on this than I am.  I have read a comment that the ECMWF's cores are all the same, a complaint that its ensemble members just follow the leader too often. I cant substantiate this.

From what Adam was telling me the new GEFS upgrade in April are suppose to be state of the art where they go more on probability or something like that.

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From what Adam was telling me the new GEFS upgrade in April are suppose to be state of the art where they go more on probability or something like that.

 

They showed some verification stats including a sandy re forecast, looks better. I think it will be available in mageval starting in march.

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