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 ID: 489199
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Slide1
The Cloud Population of the Madden-Julian Oscillation
Atmos. Sci. Colloquium, Seattle, 6 April 2012
R. Houzeand 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 DYNAMOSlide2
Indian
Ocean12
345678
Wheeler and Hendon 2004The MJODYNAMOSlide3Slide4
7N
EquatorSlide5Slide6
S
KaNCAR S-PolKa
RadarSlide7Slide8
SatelliteGlobal models
SoundingsOther island radarsShip dataShip radarsAircraft dataS-PolKaradarNCARradar
processorUW serverUW workstationsDaily Science SummariesNCAR field catalog
Project Data FlowLIghtningSlide9Slide10
Radar experiment goal
Characteristics and evolution of the MJO cloud population in the region where the disturbance builds up
Addu AtollSlide11
Supp.
Supp.
Supp.
ActiveActive
Active
Lull
Rain over area scanned by S-PolKaSlide12
Suppressed condition
echoesSlide13
Supp.
Supp.
Supp.
ActiveActive
Active
LullSlide14
Suppressed phases:
Lines of non-precipitating cloudsSlide15
Suppressed
phases: The “worm echo”Slide16
Slightly active moist layer
Clouds building at cold pool boundariesSlide17
Slightly active moist layer
Clouds building at cold pool boundariesSlide18
Cold
pool boundaries seen in differential reflectivity (ZDR)Birds?Dragonflies????Slide19
Birds caught on cameraSlide20
graupel
small ice
large non-melting ice
heavyrain
m
elting
ice
Moderate cumulonimbus begin to grow upscale
Doppler velocity
Hydrometeor typeSlide21
Supp.
Supp.
Supp.
ActiveActive
Active
LullSlide22
October 16Slide23
Refl.
RainConv.Strat.October 16Slide24
5 km
10 km
Intense
melting layermelting snow
graupel
50 dBZ!Slide25
Active phase few days later
Convection
feeding into a large MCS Slide26
Biggest MCS of first active phase:
weak unidirectional shearSlide27
Supp.
Supp.
Supp.
ActiveActive
Active
LullSlide28
Giant Rings of Convection
Larger than mesoscale organization of deep convection Slide29Slide30Slide31
Squall line in late active phase westerlies
Doppler velocity
Hydrometeor typeSlide32
Supp.
Supp.
Supp.
ActiveActive
Active
LullSlide33
Suppressed condition cloudsSlide34
Supp.
Supp.
Supp.
ActiveActive
Active
LullSlide35Slide36Slide37
Supp.
Supp.
Supp.
ActiveActive
Active
LullSlide38Slide39
Westerly Surges
November
October
Larger than mesoscale organization of deep convection Slide40
Supp.
Supp.
Supp.
ActiveActive
Active
LullSlide41Slide42
Long arc lineSlide43
Long arc linesegment on radarSlide44
Squall linein the strong westerliesSlide45
Weak stratiform in the strong westerlies Slide46
Stratiform Rain Fraction
S-PolKa S-band Stratiform Rain FractionSlide47
Supp.
Supp.
Supp.
ActiveActive
Active
LullSlide48Slide49
The most robust squall line in the strong westerlies…
…only moderate stratiform…robust momentum transportSlide50
Supp.
Supp.
Supp.
ActiveActive
Active
LullSlide51Slide52Slide53
Summary of MJO cloud population characteristics & evolution seen by the S-PolKa radar
Humidity 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 downwardSlide54
End
This research is supported by NSF grant ATM AGS-1059611, DOE grant DE-SC0001164/ER-64752, and NASA grants NNX10AM28G and NNX10AH70G