1. COST 733 Harmonisation and Applications of Weather Type Classifications for European regions Working Group 2 Implementation and development of weather type classification methods Meeting 2008/03/07-08 Augsburg

2. 2.) Agenda & Timetable Friday: 1.) Opening, welcome and organisatory things 2.) Adoption of the agenda 3.) Status and development of catalogue database Coffee break 4.) Classification techniques End 19:00? 20:30? Dinner at “Ratskeller” Saturday: 5.) 8:30? Techniques suited for synthesis in a new technique 6.) Upcoming events Coffee break 7.) Summary / Appointment of concrete working steps 8.) 12:00? Closure of the meeting

3. 4.) Classification techniques 1.) Thomas Krennert: ZAMG, WLKC733 2.) Michel Erpicum: ERPICUM, MAHERAS 3.) Andreas Philipp: LUND, SANDRA(+S), SCHUEEPP, PERRET 4.) Filippos Tymvios: NNW 5.) Radan Huth: TPCA07, TPCAV 6.) Christoph Beck: GWT, LITADVE, LITTC 7.) Piia Post: P27, Girs, Dzerdzejevskij 8.) Domingo Rasilla Alvarez: PETISCO, PCACA 9.) Pere Esteban: PCAXTR,PCAXTRKM 10.) Judith Bartholy: HBGWL, PECZELY 11.) Silvie Jourdain: LWT2, OGWL 12.) Frank Kreienkamp : CEC

4. 2010/09 2009/09 2008/09 2007/09 2006/09 2005/09 MOU – WG2: 1.) computation of time series for selected methods 2.) selection of features from the selected methods to be combined in new common method (based on re- commendations from WG3 and WG4) 3.) conception & development of new method 4.) programming of method 5.) computation of time series 6.) correction and updates (after exchange with WG3/4) 7.) presentation & release of new method 5.) techniques suited for synthesis in a new method

6. applies to any automated classification!(?) The objective of developing a new method

7. 5.) techniques suited for synthesis in a new method The objective of developing a new method should be applicable for as many purposes as possible

8. 5.) techniques suited for synthesis in a new method a) should be applicable to many purposes (harmonized) b) should be more effective = should have higher skill for applications relying upon links between circulation and surface parameters might be a contradiction in terms, but we will see... The objective of developing a new method

9. Objective of developing a new method: a) should be applicable to many purposes (harmonized) b) should be more effective = higher skill for applications How to proceed? - get a clear numerical skill ranking of cost733cat from WG4/3 a) individually for well defined application properties/measures b) overall (for all apps/props together or sets of apps/props) - find any systematic links between technical “features” and skill! - try to combine technical features of the best - check whether their combination produces enhanced skills 5.) techniques suited for synthesis in a new method

10. pessimistic / null hypothesis: the skill of a classification for a specific application (e.g. Down- scaling) is a matter of chance (as long as the target parameter is not included in classification)! => combinations of tehcniques will not lead to a better classification. optimistic / alternative hypothesis: there are certain features/techniques catching the link between circulation and surface parameters and generally enhancing the skill! Their effect is We are not the first one checking downscaling skill: check ACCORD, STARDEX, etc. in detail But we are the first ones concentrating on classifications and use such a broad bandwidth of classification methods (is it?) We can concentrate on details/methodology of classifications => What are “features... to be combined in a new common method...” ? 5.) techniques suited for synthesis in a new method

11. suggestion for defining classification “features”: I. primary features: predefined technical approach - concept for defining key patterns - similarity/distance measure - number of classes - meteorological parameters/levels used (CTC vs. WTC) - temporal configuration: seasonal, single day, sequences,.. - spatial configuration: centered vs. unweighted, etc. II. secondary features: resulting statistical properties - distribution of type frequencies - seasonal distribution of frequencies - persistence - discrimination of temp / precip / air quality - redundancy of types III. tertiary features: skill for applications - downscaling etc. 5.) techniques suited for synthesis in a new method

12. I. primary features: predefined technical approach Variations: - may be the only fundamental difference is the concept for defining key patterns? key patterns conceptually predefined by thresholds, LUND-scheme, PCA, CA,... ? - all other techniques can be varied (?): concerning similarity/distance measure: covariance, Euclidean distance, correlation, Kirchhofer, concerning number of classes: will be varied systematically! k=2 to n concerning meteorological parameters: SLP, SLP+Z500, SLP+Z500+PRECIP,... concerning temporal configuration: single days, sequences, time constrained,... concerning spatial configuration: is varied systematically yet! domains, weighting,... 5.) techniques suited for synthesis in a new method => create standalone software package that can do all this within modules?

13. thought experiment from meeting in Prague: divisive classification (mix of fundamental methods): should have a pure CT stage (independent from tmp/prc) 1. stage: CA/PCA/etc.(?) for 10(?) SLP-patterns: optimise for within cluster variability applicable to all datasets/climatology 2. stage: discrimination of within-CT var: vorticity, wind direction, etc.(?) 10 · 2 (cyclonic/anticyclonic) · 4 (N,E,S,W) = 80 types? 3. stage: discrimination of temp/precip 80 · 2 (dry/wet) · 2 (cold/warm) = 320 types ??? would have a lot of redundancy and sparse classes 5.) techniques suited for synthesis in a new method

14. 6.) Upcoming events STSMs and other activities: - Filippos Tymvios in Augsburg: NNW classification and comparison - Pere Esteban in Augsburg: Classification techniques & Evaluations - other? Meetings: 06.-07. Mar 2008: WG4 Brussels (Matthias Demuzere) 09.-10. May 2008: MCM6 Ioannina, Greece (Pavlos Kassomenos) - Prepare presentation to the MC - formulate demands from WG4/WG3 22.-24. Oct 2008 Mid-term conference & MCM7 Progress report to COST office: 15. May 2008

15. 6.) Upcoming events 22 October (Wednesday) 10.00-17.00 - Opening ceremony and sessions 23 October (Thursday) 9.00-17.00 - Sessions 19.00 - Social Dinner 24 October (Friday) 9.00-15.00 - Sessions 15.30-18.00 - COST733 Management Committee Meeting 19.00 - Cultural event 25 October (Saturday) 8.00-18.00 - Conference excursion (Tatra Mts. and vicinity) Midterm conference Cracow Deadlines: 15. Mar. 2008: pre registration? 15. Aug. 2008: abstracts 15. Sep. 2008: registration special session for presenting work of COST733: present database in a talk (20min) ! have a (philosophic) talk about the existence/impossibility of an "universal" classification (too early!) 2 key-note talks (40-45min), some solicited speakers (30min), contributed talks (20min) Radan will organise a special issue

16. 6.) Upcoming events next WG2 meetings: - how long? 2 full days? - where? France? - when? after Cracow?

17. 7.) summary / appointment of concrete steps what to do at/for meeting in Greece: - complete database with answers to questions from WG3 - present classification database, developments & plans to MC - work out systematical grouping of methods (primary, secondary, tertiary features) - communicate demands for ranking of methods/variants to WG4 & WG3 - ask/suggest parameters for ranking: SLP, TEMP, PRECIP WG2: - summarize ACCORD: any link between class techniques & skill? - summarize STARDEX: any link between class techniques & skill? - look for other literature/sources? - start thinking/working on some basic methods varied by: -- similarity/distance measure: Euclidean distance, correlation, Kirchhofer, other? -- number of classes: k= low, intermediate, high -- meteorological parameters: SLP, Z500, SLP+Z500, wind field, other? -- temporal configuration:single days, sequence 3 days, time constrained -- spatial configuration: domains for: LUND, SANDRA-CA, t-mode PCA, threshold based - start working on a standalone software package with standardized user interface for running basic methods and variants