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1. T1279 + analyses : FC from 00Z 20/9/2012. 5 days.
GC: OK. Reproduce Fig1 in Pantillon et al. for AN and HRES forecast.
2. Ensemble (size & res to be confirmed) : OK, we need also to check if the lower res ensemble proposes 2 distinct scenarios
GC: Could use ECMWF operational ensemble (T639)? Compare with uncertainty runs: (a) below is closest to operational but at lower res and without wave model
FF: 2a. Ensemble (T639) EDA/SV/SPPT/SKEB + control --> my question is : Is the resolution of the ensemble (T639) the same resolution as the operational ensemble of 2012 ? If yes we will get the same bifurcation has the one mentioned in Pantillon. If it is lower we need to check if the ensembles propose two distinct scenarios. Concerning the visualization of the ensembles We can do the same has last year's workshop with RMSE, plumes, ensemble spread, spaghettis, ... It will be very interesting to look into this for the students.
GC: Yes, we use the operational forecast ensemble at the time.
TODO: Need to decide on variables & levels to plot: e.g. MSL, geopotential, winds, temp? What levels? 925hPa, 850, 500, 350? PV : 330K?
2b. PCA and clustering --> We can try the code you have to see if we get two distinct patterns in the t+96h forecast. I still need to ask about PCA and clustering with R and the format of data needed. This part wil be a bonus if we want to have time for the uncertianty runs.
GC: OK, TODO: (1) test Linus' PCA code and report back. Use 500hPa geopotential as in paper, (2) FF to investigate use of R & format of data required.
3. Sensitivity run with ensemble, varying SST? We can try, to see if it impacts the motion of Nadine. Surface fluxes may also have an influence on the motion of Nadine. Switching of deep convection ? Maybe too radical ? Is it possible to do a sensitivity to the resolution ? The interaction between Nadine and the cutoff seems to be impacted by the resolution.
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GC: Agreed. Although no-one will run OpenIFS to produce a 'class ensemble', the exercises allow the participants to group perturbed members into different size ensembles to see what impact it has.
FF:a. Uncertainty runs EDA/SV VS SPPT/SKEB --> Do you plan do the class ensemble to see the impact of the number of members ? We do not have to run it in real time, I'll just tell you the number of students (or binomes ?)
b : if EDA/SV VS SPPT/SKEB are the same : SST sensitivity --> The question of the SST of the atmospheric model is interesting, students often think it varies whereas it is constant if I am not mistaken ? If you see a great sensitivity of the forecast to the SST in terms of intensity and track of Nadine this could be great !
5. SCM: I have the radiation exercices and convection exercices from previous workshops. It could be nice to look at the convective tendencies in Nadine's deep convection to illustrate of the convection scheme works. I am sure Peter Bechtold has great ideas about that !
On the second day, François Bouttier can also speak about optimal tresholds to use in order to deal with extremes with convective scale ensembles.
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