COST ACTION 722
‘Short-range forecasting methods of fog, visibility, and low clouds’
Report by Silas Chr. Michaelides
Chairman of Working Group 3
Statistical Methods in forecasting fog, visibility and low clouds
Ljubljana, Slovenia - 9 Setpember 2006
--------------------------------Working Group 3 (WG3) meeting was held on 9 Setpember 2006, from 0900 till 1200.
1. Welcome and adoption of the Agenda
With the start of the meeting, all members were welcomed and the Agenda was adopted.
2. Members of Working Group 3
The following six Cost Action 722 participants from five countries participated to the
meeting:
Bulgaria : Anastasiya Stoycheva, Latin Latinov
Cyprus: Silas Michaelides,
France: Harold Petithomme
Norway: John Bjørnar Bremnes
3. Review of status of tasks by members
The meeting reviewed the state of the tasks undertaken by the members of WG3.
3.1 Determine HOW to evaluate the potential of existing methods. (Task 1)
The software and the working document prepared by MeteoFrance (Harold Petithomme) are
completed and distributed to other Cost722 members (those who participate to the intercomparison project). The software has already been used in the model Inter Comparison task
and already sent to the web site. A paper is prepared for publication.
3.2 Methodology for the Selection of Predictors (Tasks 2+4)
This task was undertaken by Switzerland. A large part of the related work was completed last
year and presented before. The Swiss delegation (Adrian Scherzinger) recently sent their a
draft for their contribution to the Final Report.
3.3 Transfer and evaluate statistical methods (Task 3)
The original plan agreed in Odense was to transfer data. However things developed along
another line, so that models has been tested at different locations.
Some confusion has been about differences between models and methods.
A statistical method is very general such as Regression (linear, etc.), Decision tree, Neural
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Network, Fuzzy logic.
A model is more specific object that given some input parameters produces a forecast for
another parameter. A model is developed from a statistical method, but contains model
coefficients that has been determined in advance some how, usually called training.
An overview of what has been done follows:
Three models have been made available and worked with. These are:
a. Danish diagnostic model
b. Norwegian Neural network model made available by John Bremnes Norway
c. Hungarian decision tree model made available by Ferenc Wantuch Hungary
The progress so far is outlined below:
 The Danish model has been tested with data from Larnaca airport Cyprus, The model
has been adjusted to Cyprus data (Mikael Muskos STSM in Copenhagen)
 Hungarian model has been tested with Danish data. The plan was to investigate
possible modifications to the model during an STSM with Ferenc Wantuch visiting
Copenhagen, but this was not possible.
 The Hungarian model has been tested using data from Larnaca airport Cyprus. The
model has been adjusted to Cyprus data (STSM Ferenc Wantuch in Larnaca Cyprus)
 The Hungarian model has been tested with data from Poland
 The neural network method has been analyzed using data from Denmark
 The neural network method has been analyzed using data from Larnaca airport
Cyprus.
3.4 Improvement and innovation of statistical forecasting (Task 5) – Fuzzy-logic
Three members working under this task were absent from the meeting so it was not possible
to report on the progress. They will all contacted for submitting their report and contributions
to the Final Report (Ferenc Wantuch, Marek Jerczyński, Jadwiga Woyciechowska).
3.5 Forecasting low visibility using Artificial Neural Nets (Task 5)
The task is completed and results were submitted to PAGEOPH. John Bremnes will refine
his source code and put the ANN software (with examples from Larnaka and Gardenmoen)
on the web site (to be sent directly to Jan Cermak).
3.6 Literature Survey on existing statistical methods (Task 7)
The task has been completed and the literature has been sent to the web site. The material will
be reformatted by Anastasiya Stoycheva to appear as an attachment to the Final Report.
The Chairman concluded that by reviewing the tasks undertaken by the members of this
group it is obvious that the tasks undertaken were accompleshed with success and in due
time.
The Action evaluator, Ernst Dittman noted that some of the objectives and work of the
WG4, as inserted in the MoU, have been performed to a large extent by WG3. He has
suggested that this should be mentioned in the Final Report. The software that was developed
is really made available and this should be considered as an important contribution to WG4
tasks, although it was decided in the beginning of the Action that this should not be
undertaken by WG3.
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4. Remaining work of WG3
Bearing in mind that the Action has entered its final Phase, the remaining tasks will be as
follows:
a) All: Writing and finalizing the contribution of WG3 to the Final Report. All contributions
to be sent to the Chair before September 2006.
b) All: Prepare for EMS/ECAM meeting.
c) All: Finalise remaining publication submissions.
d) Harold Petithomme: will refine the software/documentation and put on the web (send to
Jan Cermak directly) and supply appropriate help to the members of the inter-comparison
when needed
e)
5. Final Report Tasks
It was decided that the contribution of WG3 to the Final Report will be task-oriented. Bearing
this in mind it was decided to share the writing of the respective chapter as follows:



Task 1: Harold Petithomme will write a sub-chapter on evaluation of existing
methods.
Task 2+4: After the meeting, Christoph Schmutz of MeteoSwiss expressed his
willingness to help drafting the respective sub-chapter.
Task 3: Michael Steffensen will contribute with three sub-sections on the
transferability of statistical. methods:
 Danish diagnostic methods/models used on Cyprus data (Mouskos STSM)
 John Bremnes’ ANN method/model used with Danish data
 Ferenc’s decision model on Danish data
Silas Michaelides will try to contact Ferenc Wantuch in order to ask him to
contribute on the use of the Hungarian decision tree with Cyprus data. If this is not possible,
then Ferenc’s presentation in Larnaka will be used. Also Ferenc will be asked to write on the
experimentation with ANN on Cyprus data.
Jadwiga Woyciechowska will be asked to write a sub-chapter on the use of the
Hungarian decision tree on Poland data.

Task 5: John Bremnes will contribute with two subsections
 Probabilistic forecasting of Rare events
 Probabilitstic forecasting with Artificial Neural Nets
Marek Jerczyński and Jadwiga Woyciechowska will contribute with a subchapter on Fuzzy logic.
 Task 7: Literature on Statistical Methods:
Anastasiya Stoycheva will recompile and reformat the updated version of it and add it as an
annex to the FR, following the format adopted for the presentation of the references in the
final report.
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6. Matters to be raised to the Management Committee:
To finalize the contribution to the Final Report on the Model Inter Comparison task an Expert
Meeting is needed between Harold Petithommehe and Matthieu Masbou (3 days in either
France or Germany – one person to be reimbursed).
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