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COSMO PP QPF workshop

COSMO PP QPF workshop. 8 March 2006 Langen Marco Arpagaus. Hello & thanks!. Hello to everybody … … and thanks for coming! Special thanks to Silke for the organisation!. Motivation. Improve QPF of LM! – Or at least try … How? Understand the problem! Suggest changes. Is it any better?

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COSMO PP QPF workshop

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  1. COSMO PP QPF workshop 8 March 2006 Langen Marco Arpagaus

  2. Hello & thanks! • Hello to everybody … • … and thanks for coming! • Special thanks to Silke for the organisation!

  3. Motivation Improve QPF of LM! – Or at least try … How? • Understand the problem! • Suggest changes. • Is it any better? • Would things improve in an ,ideal’ world?

  4. Motivation (2) • Task 1: Consolidate forecast failure reports and verification findings. • Task 2: Provide standardized set of model changes to be used for sensitivity studies. • Task 3: Run the sensitivity experiments and draw conclusions concerning possible improvements of the LM QPF performance. • Task 4: Run the same sensitivity experiments for moist benchmark cases.

  5. Motivation (3) • Task 1.1: Consolidate QPF related problem reports from all COSMO member states. • Task 1.2: Consolidate QPF related verification results from all COSMO member states and provide prototype cases reflecting the observed QPF problems. • Task 1.3: Condense the lists provided by tasks 1.1 and 1.2 by selecting the typical and most obvious cases illustrating the poor QPF performance of the LM. • Task 1.4: Provide LM reference version. • Task 1.5: Run test cases with LM reference version to confirm QPF problems. • Task 1.6: Reduce list of test cases recommended for sensitivity studies to a maximum of 3 cases for each LM implementation.

  6. Motivation (4) What do we want to achieve at this workshop? • Share the results we have obtained so far … • … as well as the problems we encountered! • Are we on track? • A first step towards task 1.3. • Outlook to tasks 1.4 – 1.6. • Can we profit from the common verification package?

  7. …

  8. First (online …) summary • ‘continental’ results • overprediction of pp mean in winter • overprediction of pp max in summer • ‘mediterranean’ results • modulation of results depending on upstream conditions? (flow over sea or land)

  9. First (online …) summary (2) • pp related to frontal systems (cold & warm) • pp related to orography (luv or lee) • pp dependency on flow regime • combination(s) of the above • pp dependency on upstream flow characteristics (e.g., over sea/land)  classify accordingly

  10. Methodology • synthesise! • look at day 1 pp (& check synoptic situation) • consider absolute as well as relative bias; emphasis on area mean rather than single maxima (upscaling of obs!) • look at relative contribution of stratiform and convective pp in the model • classify as stratiform or convectively dominated cases • for Italy (and Switzerland?): try to separate luv/lee effects from land/sea effects

  11. Motivation (4) What do we want to achieve at this workshop? • Share the results we have obtained so far … • … as well as the problems we encountered! • Do we need to re-formulate the task? • A first step towards task 1.3. • Outlook to tasks 1.4 – 1.6. • Can we profit from the common verification package?

  12. A first step towards task 1.3 • Agree on common verification measures. • Agree on how the cases should be described (deliverable for tasks 1.1 and 1.2). • Agree on how the verification material should be provided (deliverable for task 1.3)

  13. A first step towards task 1.3 (2) Common verification measures (COSMO Standard): • 6-hourly precipitation sums • contingency tables for thresholds 0.1 mm, 2 mm, and 10 mm • Bias, POD, FAR (after Wilks 1996) … plus individual scores.

  14. …

  15. Motivation (4) What do we want to achieve at this workshop? • Share the results we have obtained so far … • … as well as the problems we encountered! • Do we need to re-formulate the task? • A first step towards task 1.3. • Outlook to tasks 1.4 – 1.6. • Can we profit from the common verification package?

  16. Outlook to tasks 1.4 – 1.6 • Task 1.1: Consolidate QPF related problem reports from all COSMO member states. • Task 1.2: Consolidate QPF related verification results from all COSMO member states and provide prototype cases reflecting the observed QPF problems. • Task 1.3: Condense the lists provided by tasks 1.1 and 1.2 by selecting the typical and most obvious cases illustrating the poor QPF performance of the LM. • Task 1.4: Provide LM reference version. • Task 1.5: Run test cases with LM reference version to confirm QPF problems. • Task 1.6: Reduce list of test cases recommended for sensitivity studies to a maximum of 3 cases for each LM implementation.

  17. …

  18. Motivation (4) What do we want to achieve at this workshop? • Share the results we have obtained so far … • … as well as the problems we encountered! • Do we need to re-formulate the task? • A first step towards task 1.3. • Outlook to tasks 1.4 – 1.6. • Can we profit from the common verification package?

  19. …

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