mesoscale convective system heating and momentum feedbacks r. houze ncar 10 july 2006
Post on 22-Dec-2015
218 views
TRANSCRIPT
![Page 1: Mesoscale Convective System Heating and Momentum Feedbacks R. Houze NCAR 10 July 2006](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649d7f5503460f94a6319b/html5/thumbnails/1.jpg)
Mesoscale Convective SystemHeating and Momentum Feedbacks
R. Houze
NCAR 10 July 2006
![Page 2: Mesoscale Convective System Heating and Momentum Feedbacks R. Houze NCAR 10 July 2006](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649d7f5503460f94a6319b/html5/thumbnails/2.jpg)
Heating Feedbacks
TRMM studySchumacher, Houze, & Kracunas 2004
Momentum Feedbacks
TOGA COARE studiesHouze, Chen, Kingsmill, Serra &Yuter 2000Mechem, Chen & Houze 2006
![Page 3: Mesoscale Convective System Heating and Momentum Feedbacks R. Houze NCAR 10 July 2006](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649d7f5503460f94a6319b/html5/thumbnails/3.jpg)
Heating Feedbacks
![Page 4: Mesoscale Convective System Heating and Momentum Feedbacks R. Houze NCAR 10 July 2006](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649d7f5503460f94a6319b/html5/thumbnails/4.jpg)
Pre-GATE view of tropical cloud population
![Page 5: Mesoscale Convective System Heating and Momentum Feedbacks R. Houze NCAR 10 July 2006](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649d7f5503460f94a6319b/html5/thumbnails/5.jpg)
Houze et al. (1980)
Post-GATE view of tropical cloud population
![Page 6: Mesoscale Convective System Heating and Momentum Feedbacks R. Houze NCAR 10 July 2006](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649d7f5503460f94a6319b/html5/thumbnails/6.jpg)
GATE(Gamache & Houze 1983)
.60R .40R
1.17R .41R
.29R
.37R
0
.13R
.16RCOPT81
(Chong & Hauser 1989)
Water Budget of a West African Mesoscale Convective Systemover ocean (GATE) and land (COPT81)
![Page 7: Mesoscale Convective System Heating and Momentum Feedbacks R. Houze NCAR 10 July 2006](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649d7f5503460f94a6319b/html5/thumbnails/7.jpg)
Schumacherand Houze (2003)
TRMM precipitation radar rain amount subdivided intoconvective and stratiform components
Total rain
Convective rain
Stratiform rain
Stratiform rain fraction
![Page 8: Mesoscale Convective System Heating and Momentum Feedbacks R. Houze NCAR 10 July 2006](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649d7f5503460f94a6319b/html5/thumbnails/8.jpg)
Houze 1982
Heating & Cooling Processes in an MCSHeating & Cooling Processes in an MCS
![Page 9: Mesoscale Convective System Heating and Momentum Feedbacks R. Houze NCAR 10 July 2006](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649d7f5503460f94a6319b/html5/thumbnails/9.jpg)
He
igh
t (km
)
Deg K/day
Convective
Stratiform
Assumed heating profilesHeating Profiles
![Page 10: Mesoscale Convective System Heating and Momentum Feedbacks R. Houze NCAR 10 July 2006](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649d7f5503460f94a6319b/html5/thumbnails/10.jpg)
He
igh
t (km
)
Deg K/day
Assumed heating profiles
0% stratiform
40% stratiform
70% stratiform
Net Heating Profiles
Schumacher et al. 2004
![Page 11: Mesoscale Convective System Heating and Momentum Feedbacks R. Houze NCAR 10 July 2006](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649d7f5503460f94a6319b/html5/thumbnails/11.jpg)
TRMM PR 1998-2000annual precipitation, 0% stratiform, resting basic state
250 mb stream function, 400 mb heatingK/day
Schumacher et al. 2004
![Page 12: Mesoscale Convective System Heating and Momentum Feedbacks R. Houze NCAR 10 July 2006](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649d7f5503460f94a6319b/html5/thumbnails/12.jpg)
TRMM PR 1998-2000annual precipitation, 40% stratiform, resting basic state
250 mb stream function, 400 mb heatingK/day
Schumacher et al. 2004
![Page 13: Mesoscale Convective System Heating and Momentum Feedbacks R. Houze NCAR 10 July 2006](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649d7f5503460f94a6319b/html5/thumbnails/13.jpg)
zonal wind and , 9N-9S
TRMM PR 1998-2000annual precipitation, 0% stratiform, resting basic state
mb/h
Schumacher et al. 2004
![Page 14: Mesoscale Convective System Heating and Momentum Feedbacks R. Houze NCAR 10 July 2006](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649d7f5503460f94a6319b/html5/thumbnails/14.jpg)
zonal wind and , 9N-9S
TRMM PR 1998-2000annual precipitation, 40% stratiform, resting basic state
mb/h
Schumacher et al. 2004
![Page 15: Mesoscale Convective System Heating and Momentum Feedbacks R. Houze NCAR 10 July 2006](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649d7f5503460f94a6319b/html5/thumbnails/15.jpg)
zonal wind and , 9N-9S
TRMM PR 1998-2000annual precipitation, observed stratiform, resting basic state
mb/h
Schumacher et al. 2004
![Page 16: Mesoscale Convective System Heating and Momentum Feedbacks R. Houze NCAR 10 July 2006](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649d7f5503460f94a6319b/html5/thumbnails/16.jpg)
Conclusions from the Schumacher et al. Conclusions from the Schumacher et al. TRMM study:TRMM study:
4-dimensional latent heating derived from TRMM PR produces a reasonable tropical circulation response in a simple climate model—if the stratiform rain fraction is represented accurately
Increasing the stratiform rain fraction moves the circulation centers upward and strengthens the upper-level response
Horizontal variability of the stratiform rain fraction creates more vertical tilt in the wind field
![Page 17: Mesoscale Convective System Heating and Momentum Feedbacks R. Houze NCAR 10 July 2006](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649d7f5503460f94a6319b/html5/thumbnails/17.jpg)
Momentum Feedbacks
![Page 18: Mesoscale Convective System Heating and Momentum Feedbacks R. Houze NCAR 10 July 2006](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649d7f5503460f94a6319b/html5/thumbnails/18.jpg)
Houze 1982
Low level inflow
Mid level inflow
CirculationCirculation associated with idealized MCS associated with idealized MCS
![Page 19: Mesoscale Convective System Heating and Momentum Feedbacks R. Houze NCAR 10 July 2006](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649d7f5503460f94a6319b/html5/thumbnails/19.jpg)
Low-level Inflow
![Page 20: Mesoscale Convective System Heating and Momentum Feedbacks R. Houze NCAR 10 July 2006](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649d7f5503460f94a6319b/html5/thumbnails/20.jpg)
Parcel Model of Convection
Raymond and others
![Page 21: Mesoscale Convective System Heating and Momentum Feedbacks R. Houze NCAR 10 July 2006](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649d7f5503460f94a6319b/html5/thumbnails/21.jpg)
Layer Model of Convection
Moncrieff 92
![Page 22: Mesoscale Convective System Heating and Momentum Feedbacks R. Houze NCAR 10 July 2006](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649d7f5503460f94a6319b/html5/thumbnails/22.jpg)
TOGA COARE Airborne Doppler Observations of MCSs
25 convective region flightsShow deep layer of inflow to updrafts
Kingsmill & Houze 1999
![Page 23: Mesoscale Convective System Heating and Momentum Feedbacks R. Houze NCAR 10 July 2006](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649d7f5503460f94a6319b/html5/thumbnails/23.jpg)
Mid-level Inflow
![Page 24: Mesoscale Convective System Heating and Momentum Feedbacks R. Houze NCAR 10 July 2006](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649d7f5503460f94a6319b/html5/thumbnails/24.jpg)
Houze 1982
Heating & Cooling Processes in an MCSHeating & Cooling Processes in an MCS
![Page 25: Mesoscale Convective System Heating and Momentum Feedbacks R. Houze NCAR 10 July 2006](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649d7f5503460f94a6319b/html5/thumbnails/25.jpg)
Figure CONVSF
Houze 1997
100 km
Houze 1997
“rear inflow”
Idealizedradar echo pattern
Idealizedradar echo pattern
Horizontal Structure of a Mesoscale SystemMidlevel inflow can come from any direction
![Page 26: Mesoscale Convective System Heating and Momentum Feedbacks R. Houze NCAR 10 July 2006](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649d7f5503460f94a6319b/html5/thumbnails/26.jpg)
Kingsmill & Houze 1999
TOGA COARE Airborne Doppler Observations of MCSs
25 stratiform region flights
![Page 27: Mesoscale Convective System Heating and Momentum Feedbacks R. Houze NCAR 10 July 2006](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649d7f5503460f94a6319b/html5/thumbnails/27.jpg)
Kingsmill & Houze 1999
Convective region flights Stratiform region flights
TOGA COARE Airborne Doppler Observations of MCSs
![Page 28: Mesoscale Convective System Heating and Momentum Feedbacks R. Houze NCAR 10 July 2006](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649d7f5503460f94a6319b/html5/thumbnails/28.jpg)
Heating & Cooling Processes in an MCSHeating & Cooling Processes in an MCS
![Page 29: Mesoscale Convective System Heating and Momentum Feedbacks R. Houze NCAR 10 July 2006](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649d7f5503460f94a6319b/html5/thumbnails/29.jpg)
Momentum Transport
![Page 30: Mesoscale Convective System Heating and Momentum Feedbacks R. Houze NCAR 10 July 2006](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649d7f5503460f94a6319b/html5/thumbnails/30.jpg)
LeMone 1983
Buoyancy Produced Pressure Minimum in an MCS
Convective Region
![Page 31: Mesoscale Convective System Heating and Momentum Feedbacks R. Houze NCAR 10 July 2006](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649d7f5503460f94a6319b/html5/thumbnails/31.jpg)
Yang & Houze 1996
Perturbation pressure field in a simulated MCS
“midlevel inflow”
Precip.
Cloud
![Page 32: Mesoscale Convective System Heating and Momentum Feedbacks R. Houze NCAR 10 July 2006](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649d7f5503460f94a6319b/html5/thumbnails/32.jpg)
Chen et al. 1996
Sizes of MCSs observed in TOGA COARE
“Superclusters”
![Page 33: Mesoscale Convective System Heating and Momentum Feedbacks R. Houze NCAR 10 July 2006](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649d7f5503460f94a6319b/html5/thumbnails/33.jpg)
strong westerly westerlyonset
Houze et al. 2000
TOGA COARE radar data sampling relative to KW wave
![Page 34: Mesoscale Convective System Heating and Momentum Feedbacks R. Houze NCAR 10 July 2006](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649d7f5503460f94a6319b/html5/thumbnails/34.jpg)
TOGA COAREWesterly wind component at 155°E
12-15 Dec 92 21-26 Dec 92
Westerly Onset Strong Westerly
Westerlyjet
Houze et al. 2000
![Page 35: Mesoscale Convective System Heating and Momentum Feedbacks R. Houze NCAR 10 July 2006](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649d7f5503460f94a6319b/html5/thumbnails/35.jpg)
strong westerly westerlyonset
Houze et al. 2000
TOGA COARE radar data sampling relative to KW wave
![Page 36: Mesoscale Convective System Heating and Momentum Feedbacks R. Houze NCAR 10 July 2006](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649d7f5503460f94a6319b/html5/thumbnails/36.jpg)
SW NE
Houze et al. 2000
Stratiform region momentum transport in strong westerly region
MCS of 11 February 1993, as seen by ship radar
Stratiformradar echo
Downward momentumtransport in stratiform region
“midlevel inflow”
reflectivity
Doppler velocity
![Page 37: Mesoscale Convective System Heating and Momentum Feedbacks R. Houze NCAR 10 July 2006](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649d7f5503460f94a6319b/html5/thumbnails/37.jpg)
1000 km
1000
kmMoncrieff &
Klinker 1997
plan view
cross section
A B
A B
![Page 38: Mesoscale Convective System Heating and Momentum Feedbacks R. Houze NCAR 10 July 2006](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649d7f5503460f94a6319b/html5/thumbnails/38.jpg)
Stratiform region momentum transport in westerly onset region
MCS of 15 December 1992As seen by ship radar
Doppler Radial Velocity
Houze et al. 2000
0.5 km
![Page 39: Mesoscale Convective System Heating and Momentum Feedbacks R. Houze NCAR 10 July 2006](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649d7f5503460f94a6319b/html5/thumbnails/39.jpg)
Houze et al. 2000
Momentum Transport by Stratiform Region Descent
+ feedback feedback
![Page 40: Mesoscale Convective System Heating and Momentum Feedbacks R. Houze NCAR 10 July 2006](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649d7f5503460f94a6319b/html5/thumbnails/40.jpg)
strong westerly region westerlyonset region
TOGA COARE: Ship and aircraft radar data relative to Kelvin-Rossby wave structure
Houze et al. 2000
Low-level flow
![Page 41: Mesoscale Convective System Heating and Momentum Feedbacks R. Houze NCAR 10 July 2006](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649d7f5503460f94a6319b/html5/thumbnails/41.jpg)
m/s
Mechem et al. 2004
Mesoscale model simulation of MCS in westerly onset regime
Perturbation momentum structure
![Page 42: Mesoscale Convective System Heating and Momentum Feedbacks R. Houze NCAR 10 July 2006](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649d7f5503460f94a6319b/html5/thumbnails/42.jpg)
Mechem et al. 2004
Mesoscale model simulation of MCS in strong westerly regime
Perturbation momentum structure
![Page 43: Mesoscale Convective System Heating and Momentum Feedbacks R. Houze NCAR 10 July 2006](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649d7f5503460f94a6319b/html5/thumbnails/43.jpg)
Mechem et al. 2006
+ feedback
- feedback
Westerly OnsetCase
Strong Westerly
Case
Westerly MomentumFlux Convergence
400 km x 600 km
200 km x 300 km
![Page 44: Mesoscale Convective System Heating and Momentum Feedbacks R. Houze NCAR 10 July 2006](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649d7f5503460f94a6319b/html5/thumbnails/44.jpg)
Conclusions
•Layer lifting is important in large mesoscale convective systems, esp. in tropics
•Amount of stratiform precipitation in large MCSs affects large-scale circulation by making heating more “top-heavy”
•Horizontal variation of stratiform rain fraction affects vertical structure of the the large-scale circulation
•Large MCSs produce large momentum transports because of their areal extent
•Momentum feedbacks by subsiding midlevel inflows can be either positive or negative