Cirrus Production by a Mesoscale Convective System Sampled
During TWP-ICE: Analysis via Water Budget Equations
Jasmine Cetrone and Robert Houze
University of Washington
Condensation and Evaporation
• Humidity profile computed
from Darwin radiosonde
This study computes certain elements of the water
budget of a MCS observed during the Tropical Warm
Pool-International Cloud Experiment (TWP-ICE). The
precipitation efficiency can help relate global maps of
precipitation to maps of global anvil coverage, and the
amount of cirrus produced by the system affects the
radiation budget of the MCS.
SW
ANVIL
CONV.
STRATIFORM
Ac
*
ICE ANVIL
*A * * (DZ*) *
*
(DZ )
*
*
*
*
* *
A M
HEIGHT
Csu
Ccu
18
16
LW
Ecd
dq
C   A  w dz
dz
zb
Rc
Rs
(DXA)M
DXS
DXC
(DXA)I
DXA
MCS Overview
Determine error bars on calculations
Height (km)
4
2
0
0
Extend to other tropical regions
5
10
15
Specific Humidity (g kg-1)
Results over
radar domain:
Anvil
• Ice water content (IWC) calculated for anvil seen by
MMCR via a Z-IWC relationship: IWC=0.097Z0.59
Csu=2.7560×1013 kg
Esd
=3.8781×1013
• Histogram of ice water path (IWP) calculated for the
anvil; applied to the area covered by anvil in the
satellite to get the mass of total anvil (Ac+As)
kg
• MMCR sensitivity was low during TWP-ICE, resulting in
underestimation of IWC in anvil and thus total anvil
mass
Precipitation
Visible Satellite and Radar Reflectivity at 03:30 on 20 January
Convective Rain
dBZ
60
11°S
Stratiform Rain
150
200
150
30
100
25
50
20
53
32
25
13
18
11
14
4
126
127
128
129
130
131
132
133°E
50
120
0
80
-50
40
-100
20
0
15
-50
10
• Some anvil will not be accounted for as it evaporates
Storm Rain Total (mm)
39
160
Storm Rain Total (mm)
12
100
Distance from radar (km)
46
5
-100
21
14
12
-150
-100
-50
0
50
100
Distance from radar (km)
150
0
-150
-100
-50
0
50
100
150
0
8
-7
4
Distance from radar (km)
• Convective/stratiform maps computed from radar data
-14
-21
0
20 Jan
02:00
20 Jan
04:00
20 Jan
06:00
0.01
Ac+As=3.3244×1011 kg
0
7
20 Jan
00:00
Results of anvil from
satellite/MMCR method:
28
16
19 Jan
22:00
0.02
dBZ
Millimeter Cloud Radar
Height (km)
• Next steps: Extend to another MCS (23-24 Jan)
8
Ecd=1.8498×1013 kg
dq
E  A  w dz
dz
zb
CT + Csu = Rs + Esd + As
10
Ccu=3.3627×1013 kg
zt
Ccu = Rc + Ecd + Ac + CT
12
6
zt
Esd
• Errors in MMCR data amplify in calculations of anvil
mass
14
• Condensation and
evaporation terms calculated
from the following equations:
Ese
A I
s
CT
Ece
MIXED ANVIL
• Anvil mass is approximately 10% of the total rain
precipitated out by the system in the radar domain
20
• Vertical velocity profiles of
updrafts and downdrafts in
the convective and stratiform
regions computed from dualDoppler radar data
LW
Summary and Future Work
Frequency
Introduction
20 Jan
08:00
20 Jan
10:00
-28
Time 
• Maps applied to reflectivity data to give convective and
stratiform rain totals in the radar domain
• A large MCS moved toward the north over the radar
sites on 19-20 January 2006
• MCS was mainly leading convective precipitation and
trailing stratiform
• Anvil blown off toward the WNW by upper-level winds
• Total precipitation area coverage of storm uncertain:
between 1 and 2 times the actual radar area coverage
ARM Science Team Meeting, Monterey, CA, 27 March 2007
Results over
radar domain:
Rc=2.8586×1012 kg
0
0
0.5
1.0
1.5
IWP (kg m-2)
2.0
2.5
Results of anvil as a
residual of other terms:
Ac+As=Ccu+Csu-Ecd-Esd-Rc-Rs
between 3.077×1011 kg and 6.154 ×1011 kg
(for areas between 1 and 2 times the radar area coverage)
Acknowledgements
Rs=6.7226×1011 kg
We would like to thank Stacy Brodzik for her invaluable efforts in processing this data.
R=Rc+Rs=3.5208×1012 kg
NASA ESS Grant NNG05GP07H
ARM - DOE Grant DE-FG02-06ER64175