Perturbed initial conditions climate ensemble

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New member
Dear MPAS community,

First at all, I would like to congratulate WRF/WRFDA/MPAS development team because its incredible work on the creation and improvement of numerical prediction models and an adequate support community. The correct growth of a strong community is the key of investigation success.

Our researching team is carrying out a perturbed initial conditions climate ensemble forecast using MPAS and CESM (dataset ds316.1). However, we are not sure about whether perturbed initial conditions are enough to create a correct probabilistic forecast. References affirm that initial conditions information could be lost in long term forecasts.

So, is a perturbed initial conditions climate ensemble enough to characterize a probabilistic forecasting?
If not, how could we proceed in the creation of such ensemble?

We look forward to your response.

Thank you very much,
Nast Acosta García,
Harmattan International Atmosphere Researching Group.


New member
Perturbed initial conditions should be sufficient to create a probabilistic forecast. The CESM Large Ensemble was created in a similar way. They added noise (at the magnitude of round-off error) to temperature to create their 40-member ensemble I.C., see

One can also create ensembles using time-lagged I.C. That approach is fairly straight forward and typically produces a useful spread.