1. Simulations of the Piedmont test case: 20060817
PP QPF
WP 3.2
M. Milelli*, E. Oberto*, A. Parodi**
*ARPA Piemonte, Torino
**CIMA, Savona
9th COSMO General Meeting, 18-21September 2007, Athens

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18 August 2006, 00 UTC: Bracknell analysis

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17 August 2006, 18 UTC: trispettral infrared MSG image
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Rain cumulated between 17 August 17:50 UTC and 18 August 05:50 UTC

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Ticino
Toce
Sesia
+06/+30 interval
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Exp0: CTRL
Operational
+06/+30 interval
Obs.
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New experiments list:
A1: ctrl (modified microphysics)
A2: ctrl + RK + QV090
A3: ctrl + CONkfb (Kain-Fritsch/Bechtold)
A4: A2 + CONkfb (Kain-Fritsch/Bechtold)
A5: ctrl + CONmod (modified Tiedtke)
A6: A2 + CONmod (modified Tiedtke)
A7: ctrl + RK + QV110
9th COSMO General Meeting, 18-21September 2007, Athens

12. A3 and A4 are not in agreement !!!
[f(ax)-f(a1)]/f(a1)
for x from 2 to 7, for each prec. component
A3 and A4 are not in agreement !!!
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More spread in prec. but the peaks are smoothed, particularly over the mountains !
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Conclusions
The model is sensitive to the initial humidity content (A2-A7)
The modified Tiedtke scheme (A5-A6) decreases sensibly the amount of precipitation
The new Kain-Fritsch/Bechtold scheme (A3-A4) shows a dependence on the considered validation domain and, in particular:
There is a general increase of precipitation over the whole domain but with smoothed values
The smoothing is more evident in areas of complex orography
As a result we have a sharp reduction of precipitation over Piemonte region
9th COSMO General Meeting, 18-21September 2007, Athens

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Conclusions
Some conclusions can be drawn based on the results obtained for the Piedmont case study:
QPF of COSMO-Model at 7 km shows a certain insensitivity with respect to change in its physical and numerical formulation;
On average, the experimental runs are unable to capture the correct time evolution of the event (not shown here);
The main responsible for the COSMO-Model deficiencies in the QPF seems to be impossibility of a proper modelling at 7 km of deep moist convective processes in complex orography areas.
We were probably asking too much to the model…
9th COSMO General Meeting, 18-21September 2007, Athens