The Convective Cloud Population during the Buildup of the Madden- Julian Oscillation AGU Fall...
-
date post
23-Jan-2016 -
Category
Documents
-
view
215 -
download
0
Transcript of The Convective Cloud Population during the Buildup of the Madden- Julian Oscillation AGU Fall...
The Convective Cloud Population during the Buildup of the Madden-JulianOscillation
AGU Fall Meeting, San Francisco, 7 December 2011
R. Houze, S. Brodzik, J. YuanUniversity of Washington
The Convective Cloud Population during the Buildup of the Madden-JulianOscillation
Three perspectives:
A-Train
DYNAMO
TRMMStill going on!
The MJO
Wheeler and Hendon 2004
Phases of the MJO
TRMM
Phase 1 Phase 5
Phase 7Phase 3
Frequency of radar echo in “broad stratiform regions” of MCSs
Phase 7Phase 3
Phase 1 Phase 5
Frequency of radar echo in “deep convective cores”
Phase 7Phase 3
Phase 1 Phase 5
Frequency of “shallow isolated” radar echoes (anomaly)
Variation of Echo Category with MJO Phase
A-Train
Mesoscale Convective Systems (MCSs) have cold tops and large intense
raining cores
Both raining and anvil components are identified using A-Train
instruments
CMCSs SM
CSs HCSs excl.M
CSs non-HCSs
Perc
enta
ge %
a) Cloud coverage b) Contribution to precipitation
“Connected MCSs”
“Separated MCSs”
Other High CloudSystems
Non-high-cloudSystems
DYNAMO
Cloud Structures(NCAR S-PolKa radar)
Suppressed phase:
Lines of non-precipitating
clouds
Suppressed phase:
Clouds at cold pool boundaries
Suppressed phase:
Clouds at cold pool boundaries
4 km
8 km
graupel
small icelarge non-melting ice
heavy rain
Small cumulonimbus
melting snow
Small, weakstratiform area
Active phase:
Large mesoscale
system Stratiform
Convective
5 km
10 km
Robust melting layer
inLarge MCS
Convection feeding into a large MCS
Shear
Low-level westerly component, upper-level easterly component
NE
NE
SW
SW
Biggest MCS of first active phase: weak unidirectional shear
Larger-than-mesoscale Organization
Giant Rings of Convection
Westerly Surges
EndThis research is supported by NSF grant ATM AGS-1059611, DOE grant DE-SC0001164/ER-64752, and
NASA grants NNX10AM28G and NNX10AH70G
Extras
Identify each Identify each contiguouscontiguous 3D echo object 3D echo objectseen by TRMM PR seen by TRMM PR
Convective componentConvective component Stratiform componentStratiform component
Extreme characteristicExtreme characteristicContiguous 3D volume ofContiguous 3D volume ofconvective echo > 30 dBZ convective echo > 30 dBZ
Top height > 8 kmTop height > 8 km
““Deep convective coreDeep convective core”” Horizontal area > 800 kmHorizontal area > 800 km22
““Wide convective coreWide convective core””
Extreme characteristicExtreme characteristicContiguous stratiform echoContiguous stratiform echo
with horizontal area > 50 000 kmwith horizontal area > 50 000 km22
““Broad stratiform regionBroad stratiform region””
Categories of radar echoes seen by TRMM Categories of radar echoes seen by TRMM
MODIS TB11 + AMSR-E (Yuan and Houze 2010)
combined to find“cold centers” & “raining areas”
Use 260 K threshold
Locate 1st closed contour
Use 1 mm/h threshold for rain rate
Associate pixels with nearest cold center
Use 6 mm/h threshold for heavy rain
1 2 3 4 5 6 7 8Phase
Pres
sure
(hPa
)
Phases 1,8 Phases 2,3 Phases 4,5 Phases 6,7
50 E 100 E 150 E 200 E DYNAMO
Mixing ratio anomaly
1000
600
200
1000
600
200
Descent of easterlies