Robert A Houze Jr University of Washington ASR Science Team Meetings Bethesda 20 November 2014 Mesoscale Convective Systems 1 2 3 From space Frequency of MCS anvils over tropics Yuan and Houze 2010 ID: 165231
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Slide1
Anvil Clouds of Mesoscale Convective Systems
Robert A. Houze, Jr.
University of Washington
ASR Science Team Meetings, Bethesda, 20 November 2014 Slide2
Mesoscale Convective Systems
1
2
3
From spaceSlide3
Frequency of MCS anvils over tropics
Yuan and Houze 2010Slide4
W
idth
& thickness
of MCS anvils seen
by CloudSat
Yuan and Houze 2010
Africa
Indian OceanSlide5
Yuan, Houze, and
Heymsfield
2011
Africa
Indian Ocean
Internal structure of MCS
anvils seen by CloudSatSlide6
CloudSat CFADs of Large, separated
MCSs over the Maritime ContinentSlide7
Is there a framework for quantifying bulk anvil structures?Slide8
MCS anvil is the result of a life cycle process
Houze 1982Slide9
The time-integrated MCS anvil process
Extensively studied
Need to understand how anvil is related to the raining region
Mesoscale Convective SystemSlide10
Dimensions and hydrometeor content of anvils are determined by the same cloud dynamics that produce the precipitationSlide11
Breakdown of
the water
budget
After Houze et al. (1980)
A
c
A
s
Δ
Z
AC
Δ
X
ACSlide12
A
s
A
s
A
c
Δ
Z
AC
Δ
X
AC
with the constraint
(each height cat.)
Convective region water
budgetSlide13
Stratiform water budget equation
Rain not simply related to condensation
A
s
A
s
A
c
Δ
Z
AC
Δ
X
ACSlide14
A
s
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s
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c
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Total anvil water contentSlide15
A
s
A
s
A
c
Dimensions and hydrometeor content of anvils are determined by the
same cloud dynamics that produce the precipitation—need to determine them to close the MCS water budget
IWC
IWC
Δ
Z
AC
Δ
X
ACSlide16
What do we know about the bulk internal structure of MCS anvils from observations?Slide17
Anvil clouds observed by WACR at Niamey
Powell et al. 2012Slide18
Anvil clouds observed by WACR at Niamey
Powell et al. 2012Slide19
Aerosol effect on anvils
Fan et al. 2013Slide20
Take-home points:Larger MCSs are primary producers of anvils over the tropicsAnvils are a product of
lifecycle of the MCS lifecycle studies are critical
Anvil characteristics determined by environment: land, ocean, day, night, … Anvils not dynamically separate from the precipitating part of the MCS
Anvils and precipitating sectors need to be
physically consistent
Anvils and precipitating sectors are
linked via the MCS water budgetLatent heating and radiative heating are linked should not be separatedAnvils are likely affected by the aerosol environment, but… Slide21
EndThis research was supported by DOE grant DE-SC0008452 / ER-65460 and NASA grant
NNX13AQ37G Slide22
Extra SlidesSlide23
GATE—oceanic
(
Gamache
& Houze 1983)
.60R
.40R
1.17R
.41R
.29R
.37R
0
.13R
.16R
COPT81
—
continental
(
Chong & Hauser 1989)
Time-integrated Water BudgetSlide24
Sum over all cloud height categories
i
For each height category
i
with the constraint
(each height cat.)
A
s
A
s
A
c
Δ
Z
AC
Δ
X
ACSlide25
Anvil clouds observed by WACR at Niamey
Powell et al. 2012