The Cloud Population of the Madden-Julian Oscillation Atmos. Sci. Colloquium, Seattle, 6 April 2012 R. Houze and D. Hence, S. Brodzik, K. Rasmussen, S. Powell, H. Barnes, B. Dolan, K. Chakravarty, C. Burleyson, Z. Li, S. Ellis, T. Weckwerth, J. Vivekanandan, J. Hubbert, W.-C. Lee Early Results from DYNAMO
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Wheeler and Hendon 2004 The MJO 7N Equator SKa NCAR S-PolKa Radar.
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The Cloud Population of the Madden-Julian Oscillation
Atmos. Sci. Colloquium, Seattle, 6 April 2012
R. Houze
and D. Hence, S. Brodzik, K. Rasmussen, S. Powell, H. Barnes,
B. Dolan, K. Chakravarty, C. Burleyson, Z. Li,
S. Ellis, T. Weckwerth, J. Vivekanandan, J. Hubbert, W.-C. Lee
Early Results from DYNAMO
IndianOcean 1
2
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Wheeler and Hendon 2004
The MJO
DYNAMO
7N
Equator
S
Ka
NCAR S-PolKaRadar
Satellite
Global models
Soundings
Other island radars
Ship data
Ship radars
Aircraft data
S-PolKaradar
NCARradarprocessor
UW server UW workstations
Daily Science Summaries
NCAR field catalog
Project Data Flow
LIghtning
Radar experiment goal
Characteristics and evolution of the MJO cloud population in the region where the disturbance builds up
Addu Atoll
Supp. Supp. Supp.ActiveActive ActiveLull
Rain over area scanned by S-PolKa
Suppressed conditionechoes
Supp. Supp. Supp.ActiveActive ActiveLull
Suppressed phases:
Lines of non-precipitating
clouds
Suppressed phases: The “worm echo”
Slightly active moist layer
Clouds building at cold pool boundaries
Slightly active moist layer
Clouds building at cold pool boundaries
Cold pool boundaries seen
in differential reflectivity
(ZDR)
Birds?Dragonflies?
???
Birds caught on camera
graupel
small ice large non-melting ice
heavyrain
meltingice
Moderate cumulonimbus begin to grow upscale
Doppler velocity
Hydrometeor type
Supp. Supp. Supp.ActiveActive ActiveLull
October 16
Refl. Rain
Conv.
Strat.
October 16
5 km
10 km
Intense melting layer
melting snow
graupel
50 dBZ!
Active phase few days later
Convection feeding into a large MCS
Biggest MCS of first active phase: weak unidirectional shear
Supp. Supp. Supp.ActiveActive ActiveLull
Giant Rings of Convection
Larger than mesoscale
organization of deep
convection
Squall line in late active phase westerlies
Doppler velocity
Hydrometeor type
Supp. Supp. Supp.ActiveActive ActiveLull
Suppressed condition clouds
Supp. Supp. Supp.ActiveActive ActiveLull
Supp. Supp. Supp.ActiveActive ActiveLull
Westerly Surges
November
October
Larger than mesoscale
organization of deep
convection
Supp. Supp. Supp.ActiveActive ActiveLull
Long arc line
Long arc linesegment on
radar
Squall linein the strong westerlies
Weak stratiform in the strong westerlies
Str
atifo
rm R
ain
Fra
ctio
nS-PolKa S-band Stratiform Rain Fraction
Supp. Supp. Supp.ActiveActive ActiveLull
The most robust squall line in the
strong westerlies…
…only moderate stratiform
…robust momentum transport
Supp. Supp. Supp.ActiveActive ActiveLull
Summary of MJO cloud population characteristics & evolution seen by the S-PolKa radarHumidity gradient layers monitored & measuredCloud lines dominate in highly suppressed periodCold pools are first stage of convective population Graupel & other ice lofted & input into stratiform regionsConvection enhanced inside stratiform regionsMCS development strongest in weak shearShear inhibits stratiform region formation Westerlies organize convection on larger than mesoscaleSquall lines form in westerlies at back of active zoneSquall lines transport momemtum downward
End
This research is supported by NSF grant ATM AGS-1059611, DOE grant DE-SC0001164/ER-64752, and NASA grants NNX10AM28G and NNX10AH70G