1. 14th Aladin Workshop, Innsbruck Evaluation of ALADIN mesoscale precipitation forecasts in the southern Alpine area Christoph Wittmann IMG, University of Vienna (master thesis)

2. 14th Aladin Workshop, Innsbruck Topography

3. Method  Selection of heavy and moderate wintertime/fall precipitation events (1999 – 2003) in connection with a southerly flow → 62 days belonging to 13 periods (duration: 3 – 8 days)  Analysis of typical observed precipitation patterns (rain gauge, areal averages)  Comparison of observed and modelled precipitation patterns, analysis regarding systematical deviations in the different areas  Comparison of observed and modelled inflow soundings (Udine,...) → additional prognostic information?

4. 14th Aladin Workshop, Innsbruck Data OBSERVATIONS: TAWES: rain gauge, areal average HZB: rain gauge, areal average Soundings (especially Udine) Weather charts archive (ZAMG, GFS) Radar ALADIN-VIENNA (AVI) ( resolution: 9.6 km ) Model output (AVI00, AVI12): selected fields AVI: areal average Pseudotemps

5. 14th Aladin Workshop, Innsbruck Areas 15 16 17 1918 14 25 24

6. 14th Aladin Workshop, Innsbruck Results (a) Observed precipitation patterns:  Areas 18 and 16 with the highest areal means  Area 17 with the lowest areal means Stations with highest precipitation amounts (52 overall):

7. 14th Aladin Workshop, Innsbruck Results (b) Observed precipitation pattern:

8. 14th Aladin Workshop, Innsbruck Results (c) Systematical analysis:

9. 14th Aladin Workshop, Innsbruck Results (d) OBSERVATION ↔ ALADIN:

10. 14th Aladin Workshop, Innsbruck Preliminary Conclusions & Outlook Analysis of observational data gives clear idea regarding primary affected regions in the south of Austria (area, stations) Observed precipitation pattern with highest variability in eastern part of area 18 and western part of area 19 Three areas can be outlined, showing significant tendencies with respect to over/underestimation of areal averages Comparison observation ↔ Aladin reveals existence of a “problem- area” (responsible for major part of underestimation in areas 18 and 19)  Information from upstream soundings (observed, modelled) → additional prognostic information ( → “p.a.”) ?  Further analysis: Relation between flow direction, precipitation patterns and deviations observation – Aladin (especially “p.a.”)  Information from radar data → role of convection?