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Data is provided for a single 5 day forecast starting from 20th Sept 2012, as used in the paper by Pantillon et al.
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In this task, we'll look at the difference between the forecast and the analysis by using "root-mean-square error" (RMSE) curves as a way of summarising the performance of the forecast. Root-mean square error curves are a standard measure to determine forecast error compared to the analysis and several of the exercises will use them. The RMSE is computed by taking the square-root of the mean of the forecast difference between the HRES and analyses.
Using Right-click the hres_rmse.mv icon, right-click, select 'Edit' and plot the RMSE curve for z500. RMSE of the 500hPa geopotential is a standard measure for assessing forecast model performance at ECMWF (for more information see: http://www.ecmwf.int/en/forecasts/quality-our-forecasts).
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Repeat for both geographical regions: mapType=1 (Atlantic) and mapType=2 (France).
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1. What do the RMSE curves show? 2. Why are the curves different between the two regions? |
Task 2: Compare forecast to analysis
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to
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analysis
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b) Use the hres_to_an_diff.mv icon and plot the difference map between a the HRES forecast date and the analysis for z500 and mslp.
We suggest looking at only one forecast lead-time (run) but when working in teams, different members of the team could choose a different forecast.
If you want to change the default date, edit the following line:
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#Model run
run=2013-10-24 |
Task 3: Team working
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1. What differences can be seen? 2. What can said about the quality of the forecast in positioning of the Hurricane and cut-off N.Atlantic low |
Look at other fields to study the forecast. For example, jet position, total precipitation (tp).
Other plot types
As for the analyses, the macros hres_1x1.mv, hres_2x2.mv and hres_xs.mv can be used to plot and animate fields or overlays of fields from the HRES forecast.
Group working suggestions
As a groupAs a team, discuss the plots & parameters to address the questions above given what you see in the error growth curves and maps from task 2.
Look at the difference between forecast and analysis to understand the error in the forecast, particularly the starting formation and final error.Team members can limit to a certain date and choose particular parameters for team discussion.
Remember to save (or print) plots of interest for later group discussion.presentation.
TODO: What more do we need to ask the students to do here?
- Plot and animate MSL + 500hPa maps showing track of Nadine
> 1 : Nadine MSLP and T2m (or better SST) tracking 15-20 september
> 2 : Satellite views on the 20th (provided by Etienne, if possible to put on the VM)
> 3 : Studying of the horizontal maps (analysis + forecasts)
> 4 : Studying and building of the vertical x-sections (analysis + forecasts)
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