Mesoscale Convective Systems: Recent Observational and Diagnostic Studies Robert Houze
description
Transcript of Mesoscale Convective Systems: Recent Observational and Diagnostic Studies Robert Houze
![Page 1: Mesoscale Convective Systems: Recent Observational and Diagnostic Studies Robert Houze](https://reader035.fdocuments.in/reader035/viewer/2022062502/56814bfd550346895db8fa59/html5/thumbnails/1.jpg)
Mesoscale Convective Systems: Recent Observational and Diagnostic Studies
Robert Houze
Department of Atmospheric SciencesUniversity of Washington
![Page 2: Mesoscale Convective Systems: Recent Observational and Diagnostic Studies Robert Houze](https://reader035.fdocuments.in/reader035/viewer/2022062502/56814bfd550346895db8fa59/html5/thumbnails/2.jpg)
DEFINITION
Mesoscale Convective System (MCS)
A cumulonimbus cloud system that produces a contiguous precipitation area ~100 km or more in at least one direction
![Page 3: Mesoscale Convective Systems: Recent Observational and Diagnostic Studies Robert Houze](https://reader035.fdocuments.in/reader035/viewer/2022062502/56814bfd550346895db8fa59/html5/thumbnails/3.jpg)
Questions
Why do tropical and midlatitude MCSs look different?
Does layer lifting occur in a mature MCS?
Is rear inflow really from the rear?
What controls the size of MCSs?
What controls the movement of MCSs?
![Page 4: Mesoscale Convective Systems: Recent Observational and Diagnostic Studies Robert Houze](https://reader035.fdocuments.in/reader035/viewer/2022062502/56814bfd550346895db8fa59/html5/thumbnails/4.jpg)
Why do tropical and midlatitude MCSs look different?
![Page 5: Mesoscale Convective Systems: Recent Observational and Diagnostic Studies Robert Houze](https://reader035.fdocuments.in/reader035/viewer/2022062502/56814bfd550346895db8fa59/html5/thumbnails/5.jpg)
Houze et al. 1989, 1990
Tropical & midlatitudes“Symmetric”
Midlatitudes(later stages)“Asymmetric”
Radarreflectivity
Conv.
Strat.
![Page 6: Mesoscale Convective Systems: Recent Observational and Diagnostic Studies Robert Houze](https://reader035.fdocuments.in/reader035/viewer/2022062502/56814bfd550346895db8fa59/html5/thumbnails/6.jpg)
Skamarock et al. 94
Symmetric
MCV
(Tropics & midlatitudes)
No Coriolis Coriolis
Asymmetric(Midlatitudes)
![Page 7: Mesoscale Convective Systems: Recent Observational and Diagnostic Studies Robert Houze](https://reader035.fdocuments.in/reader035/viewer/2022062502/56814bfd550346895db8fa59/html5/thumbnails/7.jpg)
Parcel vs. layer lifting in an MCS
![Page 8: Mesoscale Convective Systems: Recent Observational and Diagnostic Studies Robert Houze](https://reader035.fdocuments.in/reader035/viewer/2022062502/56814bfd550346895db8fa59/html5/thumbnails/8.jpg)
Parcel viewpointZipser 1977
CrossoverZone
![Page 9: Mesoscale Convective Systems: Recent Observational and Diagnostic Studies Robert Houze](https://reader035.fdocuments.in/reader035/viewer/2022062502/56814bfd550346895db8fa59/html5/thumbnails/9.jpg)
Layer viewpoint: Bryan and Fritsch 2000
“Slab” or Layer Overturning
MAUL
![Page 10: Mesoscale Convective Systems: Recent Observational and Diagnostic Studies Robert Houze](https://reader035.fdocuments.in/reader035/viewer/2022062502/56814bfd550346895db8fa59/html5/thumbnails/10.jpg)
TOGA COARE Airborne Doppler Observations of MCSs
Convective region flights
0.5-4.5 km
Note!
Layer viewpoint: Kingsmill & Houze 1999
0ze
![Page 11: Mesoscale Convective Systems: Recent Observational and Diagnostic Studies Robert Houze](https://reader035.fdocuments.in/reader035/viewer/2022062502/56814bfd550346895db8fa59/html5/thumbnails/11.jpg)
Layer viewpoint: Mechem, Houze, & Chen 2002
TOGA COARE23 Dec 92
200X (km)
150 250200150 250X (km)
Z (k
m)
Y (k
m)
0
2
4
6
8
10
12
14
50
100
150
![Page 12: Mesoscale Convective Systems: Recent Observational and Diagnostic Studies Robert Houze](https://reader035.fdocuments.in/reader035/viewer/2022062502/56814bfd550346895db8fa59/html5/thumbnails/12.jpg)
1000 km
1000
km
Moncrieff & Klinker 1997
plan view
cross section
A B
A B
![Page 13: Mesoscale Convective Systems: Recent Observational and Diagnostic Studies Robert Houze](https://reader035.fdocuments.in/reader035/viewer/2022062502/56814bfd550346895db8fa59/html5/thumbnails/13.jpg)
Is rear inflow really from the rear?
![Page 14: Mesoscale Convective Systems: Recent Observational and Diagnostic Studies Robert Houze](https://reader035.fdocuments.in/reader035/viewer/2022062502/56814bfd550346895db8fa59/html5/thumbnails/14.jpg)
Diversity of stratiform structure: Parker & Johnson 2000PATTERNS OFEVOLUTION OF STRATIFORM PRECIPITATION IN MIDLATITUDESQUALL LINES
![Page 15: Mesoscale Convective Systems: Recent Observational and Diagnostic Studies Robert Houze](https://reader035.fdocuments.in/reader035/viewer/2022062502/56814bfd550346895db8fa59/html5/thumbnails/15.jpg)
Kingsmill & Houze 1999 Documented airflow
shown by airborne Doppler inTOGA COARE MCSs
Stratiform region flights
0°C
![Page 16: Mesoscale Convective Systems: Recent Observational and Diagnostic Studies Robert Houze](https://reader035.fdocuments.in/reader035/viewer/2022062502/56814bfd550346895db8fa59/html5/thumbnails/16.jpg)
0 192Horizontal Distance (km)
11
0
Hei
ght (
km)
192
11
0
Hei
ght (
km)
0
90 km
Horizontal Distance (km) 100 km
Refl.
Radial Velocity3.5 km level
JASMINE: Ship radar, Bay of Bengal, 22 May 1999
RadialVelocity
Reflectivity1.5 km level
![Page 17: Mesoscale Convective Systems: Recent Observational and Diagnostic Studies Robert Houze](https://reader035.fdocuments.in/reader035/viewer/2022062502/56814bfd550346895db8fa59/html5/thumbnails/17.jpg)
0 192Horizontal Distance (km)
12
0
Hei
ght (
km)
192Horizontal Distance (km)
12
0
Hei
ght (
km)
0Horizontal Distance (km) 100 km
Radial Velocity3.5 km level
JASMINE: Ship radar, Bay of Bengal, 22 May 1999
Reflectivity1.5 km level
Horizontal Distance (km) 100 km
Refl.
Radial Velocity3.5 km level
JASMINE: Ship radar, Bay of Bengal, 22 May 1999
RadialVelocity
Reflectivity1.5 km level
90 km
![Page 18: Mesoscale Convective Systems: Recent Observational and Diagnostic Studies Robert Houze](https://reader035.fdocuments.in/reader035/viewer/2022062502/56814bfd550346895db8fa59/html5/thumbnails/18.jpg)
Factors determining the size of MCSICAPE, sustainability, diurnal cycle
![Page 19: Mesoscale Convective Systems: Recent Observational and Diagnostic Studies Robert Houze](https://reader035.fdocuments.in/reader035/viewer/2022062502/56814bfd550346895db8fa59/html5/thumbnails/19.jpg)
Chen et al. 1996
Sizes of MCSs observed in TOGA COARE
“Super Convective Systems”(SCS)
![Page 20: Mesoscale Convective Systems: Recent Observational and Diagnostic Studies Robert Houze](https://reader035.fdocuments.in/reader035/viewer/2022062502/56814bfd550346895db8fa59/html5/thumbnails/20.jpg)
Kingsmill & Houze 1999
![Page 21: Mesoscale Convective Systems: Recent Observational and Diagnostic Studies Robert Houze](https://reader035.fdocuments.in/reader035/viewer/2022062502/56814bfd550346895db8fa59/html5/thumbnails/21.jpg)
Examplesof TOGACOAREMCSs
Satellite IR overlaid with A/C
radar
100 km
![Page 22: Mesoscale Convective Systems: Recent Observational and Diagnostic Studies Robert Houze](https://reader035.fdocuments.in/reader035/viewer/2022062502/56814bfd550346895db8fa59/html5/thumbnails/22.jpg)
Yuter & Houze 1998CS map Convective echo
Stratiform echo Satellite IR
% o
f grid
% o
f grid
Mea
n IR
tem
p (K
)
x (km)
y(km)
![Page 23: Mesoscale Convective Systems: Recent Observational and Diagnostic Studies Robert Houze](https://reader035.fdocuments.in/reader035/viewer/2022062502/56814bfd550346895db8fa59/html5/thumbnails/23.jpg)
Statistics for all TOGA COARE satellite/radar comparisons
Percent of 24 km square grid covered by A/C radar echo in all the MCS
Yuter & Houze 1998
![Page 24: Mesoscale Convective Systems: Recent Observational and Diagnostic Studies Robert Houze](https://reader035.fdocuments.in/reader035/viewer/2022062502/56814bfd550346895db8fa59/html5/thumbnails/24.jpg)
Portion of 240 km scale grid covered by convective radar echo
Statistics for all TOGA COARE satellite/radar comparisons
Yuter & Houze 1998
![Page 25: Mesoscale Convective Systems: Recent Observational and Diagnostic Studies Robert Houze](https://reader035.fdocuments.in/reader035/viewer/2022062502/56814bfd550346895db8fa59/html5/thumbnails/25.jpg)
Schumacher & Houze 2003
TRMM Precipitation radar:% of 2.5 deg grid covered by stratiform radar echo
Annual Average
![Page 26: Mesoscale Convective Systems: Recent Observational and Diagnostic Studies Robert Houze](https://reader035.fdocuments.in/reader035/viewer/2022062502/56814bfd550346895db8fa59/html5/thumbnails/26.jpg)
Factors determining the movement of MCS:Waves in the environment, cold pool dynamics
![Page 27: Mesoscale Convective Systems: Recent Observational and Diagnostic Studies Robert Houze](https://reader035.fdocuments.in/reader035/viewer/2022062502/56814bfd550346895db8fa59/html5/thumbnails/27.jpg)
Nakazawa 1988
INTRASEASONALENSEMBLE VARIATION
SUB-ENSEMBLE
MESOSCALE CONVECTIVE SYSTEM
![Page 28: Mesoscale Convective Systems: Recent Observational and Diagnostic Studies Robert Houze](https://reader035.fdocuments.in/reader035/viewer/2022062502/56814bfd550346895db8fa59/html5/thumbnails/28.jpg)
Chen, Houze,& Mapes 1996
AnalyzedIR data
3°N-10°S208°K threshold
IN TOGA COARE
MCSs moved individually
with wave much of the
time 12
13
15
14
Longitude
Tim
e (d
ay)
A/Cflights
on 12-14Dec
![Page 29: Mesoscale Convective Systems: Recent Observational and Diagnostic Studies Robert Houze](https://reader035.fdocuments.in/reader035/viewer/2022062502/56814bfd550346895db8fa59/html5/thumbnails/29.jpg)
Serra & Houze 2002
TEPPS—East Pacific ITCZ
Ship radardata
Easterly wave and cold pool propagation hard to distinguish
![Page 30: Mesoscale Convective Systems: Recent Observational and Diagnostic Studies Robert Houze](https://reader035.fdocuments.in/reader035/viewer/2022062502/56814bfd550346895db8fa59/html5/thumbnails/30.jpg)
equator
40NJASMINE: May 1999
60E 100E
NOAA Ship R.H. Brown
![Page 31: Mesoscale Convective Systems: Recent Observational and Diagnostic Studies Robert Houze](https://reader035.fdocuments.in/reader035/viewer/2022062502/56814bfd550346895db8fa59/html5/thumbnails/31.jpg)
JASMINE IR sequence
(courtesy P. Zuidema)
![Page 32: Mesoscale Convective Systems: Recent Observational and Diagnostic Studies Robert Houze](https://reader035.fdocuments.in/reader035/viewer/2022062502/56814bfd550346895db8fa59/html5/thumbnails/32.jpg)
Webster et al. 2002 IR over Bay of Bengal during JASMINE
Ship track
5 10 25 302015May 1999
![Page 33: Mesoscale Convective Systems: Recent Observational and Diagnostic Studies Robert Houze](https://reader035.fdocuments.in/reader035/viewer/2022062502/56814bfd550346895db8fa59/html5/thumbnails/33.jpg)
Mapes et al. (2002)
West Coast of
South Am.
GravityWave
hypothesis
![Page 34: Mesoscale Convective Systems: Recent Observational and Diagnostic Studies Robert Houze](https://reader035.fdocuments.in/reader035/viewer/2022062502/56814bfd550346895db8fa59/html5/thumbnails/34.jpg)
JASMINEMCS
![Page 35: Mesoscale Convective Systems: Recent Observational and Diagnostic Studies Robert Houze](https://reader035.fdocuments.in/reader035/viewer/2022062502/56814bfd550346895db8fa59/html5/thumbnails/35.jpg)
JASMINEMCS
![Page 36: Mesoscale Convective Systems: Recent Observational and Diagnostic Studies Robert Houze](https://reader035.fdocuments.in/reader035/viewer/2022062502/56814bfd550346895db8fa59/html5/thumbnails/36.jpg)
Carbone et al. 2002
WSR88-Dradar dataover U.S.in time/
longitudeformat
![Page 37: Mesoscale Convective Systems: Recent Observational and Diagnostic Studies Robert Houze](https://reader035.fdocuments.in/reader035/viewer/2022062502/56814bfd550346895db8fa59/html5/thumbnails/37.jpg)
ConclusionsCoriolis effect explains why midlatitude MCSs exhibit asymmetry and develop MCVs as they evolve—and why tropical MCSs don’t have asymmetryParcel lifting gives way to layer lifting in mature MCSs when potentially unstable inflow air becomes moistened—circulations become mesoscale!Midlevel inflow enters stratiform regions from various directions—controlled by environment shearMax size of MCSs related to sustainability of low-level moist inflow—get biggest systems over oceans and with LLJsMCSs motion may be determined by waves propagating through the environment—gravity waves, inertio-gravity waves,…