1 COSMO GM, Athens/2007 |

E. Zala; D. Leuenberger

Update on Weather-Situation Dependent COSMO-7 Verification against Radar Data

Results of 2006

Emanuele Zala, Daniel Leuenberger

MeteoSwiss

2 COSMO GM, Athens/2007 |

E. Zala; D. Leuenberger

Data Sets and Methodology

RADAR• Radar: 24h precipitation sums

from 06 UTC to 06 UTC• MeteoSwiss network composite

„rain“ product• horizontal resolution: 2x2km• visibility-, clutter- and bias-

corrected

COSMO-7 model:• +06h to +30h precipitation sums

from all 00UTC runs• horizontal resolution 7x7km

BIAS correction map of radar dataagainst rain gauges(Long-term corrections)

3 COSMO GM, Athens/2007 |

E. Zala; D. Leuenberger

Data Sets and Methodology

RADAR fields mapped on COSMO-7 grid:

Radar grid (2x2km) LM grid (7x7km)

4 COSMO GM, Athens/2007 |

E. Zala; D. Leuenberger

Weather Type Classification

• subjective• mainly based on 500hPa geopotential/winds • classes:

year low high flat N NE E SE S SW W NW

2004 35 99 58 14 10 1 7 13 50 46 31

2005 36 108 54 18 20 1 4 7 57 35 25

2006 20 91 41 17 9 0 6 7 75 49 50

5 COSMO GM, Athens/2007 |

E. Zala; D. Leuenberger

Weather Class „LOW“ (20 days)

6 COSMO GM, Athens/2007 |

E. Zala; D. Leuenberger

Weather Class „HIGH“ (91 days)

7 COSMO GM, Athens/2007 |

E. Zala; D. Leuenberger

Weather Class „FLAT“ (41 days)

8 COSMO GM, Athens/2007 |

E. Zala; D. Leuenberger

Weather Class „NORTH“ (17 days)

9 COSMO GM, Athens/2007 |

E. Zala; D. Leuenberger

Weather Class „SW“ (75 days)

10 COSMO GM, Athens/2007 |

E. Zala; D. Leuenberger

Weather Class „WEST“ (49 days)

11 COSMO GM, Athens/2007 |

E. Zala; D. Leuenberger

Weather Class „NW“ (50 days)

12 COSMO GM, Athens/2007 |

E. Zala; D. Leuenberger

Conclusions

• Smaller biases in weak advection

• Overestimation on upstream side of topography

• Tendency to underestimation in flat terrain

• Special: SW-flow: Large underestimation over Jura mountains and Swiss Plateau

• Similar results in 2004 and 2005