kain-fritsch convection scheme: an update
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Kain-Fritsch convection scheme: an update. Marco Arpagaus MeteoS wiss. Outline. Good News and Bad News Some test-case results Improvements needed More sensitivity tests More output Conclusion and Outlook. Good News and Bad News. - PowerPoint PPT PresentationTRANSCRIPT
Kain-Fritsch convection scheme:an update
Marco ArpagausMeteoSwiss
Marc
o.A
rpagaus@
Mete
oSw
iss.
chC
OSM
O G
enera
l M
eeti
ng,
24
-26
Sep 2
00
3,
Langen
2
Outline
Good News and Bad NewsSome test-case resultsImprovements neededMore sensitivity testsMore outputConclusion and Outlook
Marc
o.A
rpagaus@
Mete
oSw
iss.
chC
OSM
O G
enera
l M
eeti
ng,
24
-26
Sep 2
00
3,
Langen
3
Good News and Bad News
Cleaned and reasonably well tested version available with LM version 3.6.However, still a lot to be tested and improved (see below).Poor performance on vector machines, but ok for MPPs; can not be optimized without substantial recoding.Alternative implementations of Tiedtke and Kain-Fritsch schemes available (from Peter Bechtold, ECMWF); will be added to the LM as alternative CPSs as soon as possible.Kain-Fritsch is already being experimentally used for the COSMO LEPS.
Marc
o.A
rpagaus@
Mete
oSw
iss.
chC
OSM
O G
enera
l M
eeti
ng,
24
-26
Sep 2
00
3,
Langen
4
Some test-case results: 12.06.2003 00UTC
Synoptic situation: High-pressure system over large parts of central Europe; convection over Switzerland in second half of the day.Poor forecast (complaints by forecasters) by aLMo: Can the Kain-Fritsch scheme provide a better forecast?
Marc
o.A
rpagaus@
Mete
oSw
iss.
chC
OSM
O G
enera
l M
eeti
ng,
24
-26
Sep 2
00
3,
Langen
5
Some test-case results: 12.06.2003 00UTC
Kain-Fritsch (nudging, GME) Tiedtke (nudging, GME)
09-12 UTCKain-Fritsch (nudging, IFS)
Marc
o.A
rpagaus@
Mete
oSw
iss.
chC
OSM
O G
enera
l M
eeti
ng,
24
-26
Sep 2
00
3,
Langen
6
Some test-case results: 12.06.2003 00UTC
Kain-Fritsch (nudging, GME) Tiedtke (nudging, GME)
12-15 UTCKain-Fritsch (nudging, IFS)
Marc
o.A
rpagaus@
Mete
oSw
iss.
chC
OSM
O G
enera
l M
eeti
ng,
24
-26
Sep 2
00
3,
Langen
7
Some test-case results: 12.06.2003 00UTC
Kain-Fritsch (nudging, GME) Tiedtke (nudging, GME)
15-18 UTCKain-Fritsch (nudging, IFS)
Marc
o.A
rpagaus@
Mete
oSw
iss.
chC
OSM
O G
enera
l M
eeti
ng,
24
-26
Sep 2
00
3,
Langen
8
Some test-case results: 12.06.2003 00UTC
Kain-Fritsch (nudging, GME) Tiedtke (nudging, GME)
18-21 UTCKain-Fritsch (nudging, IFS)
Marc
o.A
rpagaus@
Mete
oSw
iss.
chC
OSM
O G
enera
l M
eeti
ng,
24
-26
Sep 2
00
3,
Langen
9
Some test-case results: 12.06.2003 00UTC
Kain-Fritsch (nudging, GME) Tiedtke (nudging, GME)
21-24 UTCKain-Fritsch (nudging, IFS)
Marc
o.A
rpagaus@
Mete
oSw
iss.
chC
OSM
O G
enera
l M
eeti
ng,
24
-26
Sep 2
00
3,
Langen
10
Some test-case results: 24.07.2003 00UTC
Synoptic situation: Retreat of a high-pressure ridge over southern Europe and passage of an upper-level trough; short-wave disturbance with associated cold front crosses Germany in the evening; pre-frontal convection in the afternoon.Poor forecast (complaints by forecasters) by LM at DWD: Can the Kain-Fritsch scheme provide a better forecast?
Marc
o.A
rpagaus@
Mete
oSw
iss.
chC
OSM
O G
enera
l M
eeti
ng,
24
-26
Sep 2
00
3,
Langen
11
Some test-case results: 24.07.2003 00UTC
Kain-Fritsch (nudging, GME) Tiedtke (nudging, GME)
Kain-Fritsch (interpolation, GME)12-18 UTC
Marc
o.A
rpagaus@
Mete
oSw
iss.
chC
OSM
O G
enera
l M
eeti
ng,
24
-26
Sep 2
00
3,
Langen
12
Improvements needed
Stripes of low precipitation amounts in the grid-scale precipitation output fields: insufficient removal of vertical instabilities? Related question: what are reasonable vertical velocities at the grid-scale?Did you observe any obvious shortcomings of the scheme?
Marc
o.A
rpagaus@
Mete
oSw
iss.
chC
OSM
O G
enera
l M
eeti
ng,
24
-26
Sep 2
00
3,
Langen
13
More sensitivity tests
Feedbacks provided by the Kain-Fritsch schemetemperature and water vapour only (same as Tiedtke scheme)temperature and all hydrometeors the host model ‘knows’
Triggeramount of temperature perturbation at the LCLdependence of temperature perturbation on vertical velocity and/or relative humiditysensitivity to averaging (of vertical velocity, forcing fields)
Closuretime scale
Interplay of deep, shallow, and midlevel convectionDependence of scheme on calling frequency
Marc
o.A
rpagaus@
Mete
oSw
iss.
chC
OSM
O G
enera
l M
eeti
ng,
24
-26
Sep 2
00
3,
Langen
14
More output
cloud cover (for radiation scheme!) --- do it analogous to Tiedtke scheme?cloud base & cloud topCAPE, CINmassflux at cloud base…
Marc
o.A
rpagaus@
Mete
oSw
iss.
chC
OSM
O G
enera
l M
eeti
ng,
24
-26
Sep 2
00
3,
Langen
15
Conclusion and Outlook
Code available for extensive testing; experimental usage encouraged (feedback, please!).Missing output fields will be added within the next few weeks. Detailed case and sensitivity studies pending; anyone willing to do parallel runs (on MPPs …)?Implementation of alternative implementations of Tiedtke (IFS) and Kain-Fritsch (Meso-NH, Bechtold) schemes as soon as possible.