...
In this case study, there are two operational ensemble datasets and additional datasets created with the OpenIFS model, running at lower resolution, where the initial and model uncertainty are switched off. The OpenIFS ensembles are discussed in more detail in later exercises and are not covered in this exercise.
An ensemble forecast consists of:
- Control forecast (unperturbed)
- Perturbed ensemble members. Each member will use slightly different initial data conditions and include model uncertainty pertubations.
2012 Operational ensemble
...
In these tasks, the performance of the ensemble forecast is studied.
| Panel | ||||
|---|---|---|---|---|
| ||||
|
...
The purpose of this task is to explore the difference in more detail and look in particular at the 'ensemble spread'.
Refer to the storm track plots in the handout in this exercise.
Use the ens_to_an.mv icon and plot the MSLP and wind fields. This will produce plots showing: the mean of all the ensemble forecasts, the spread of the ensemble forecasts, the operational HRES deterministic forecast and the analysis.
...
| Panel | ||||
|---|---|---|---|---|
| ||||
How does the mean of the ensemble forecasts compare to the HRES & analysis? |
...
Does the ensemble spread capture the error in the forecast? |
...
What other comments can you make about the ensemble spread? |
If time:
...
- set the 'members=' option to change the number of members in the spread plots.
e.g. try a "reduced" ensemble by only using the first 5 ensemble members: "members=[1,2,3,4,5]".
...