COSMO PP QPF workshop

COSMO PP QPF workshop

8 March 2006Langen

Marco Arpagaus

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

MotivationImprove QPF of LM! – Or at least try …

How? Understand the problem! Suggest changes. Is it any better? Would things improve in an ,ideal’ world?

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.

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.

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?

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)

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

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

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?

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)

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.


package?

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.


package?

COSMO PP QPF workshop

Documents

Transcript of COSMO PP QPF workshop