Robert Houze

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Mesoscale Phenomena of the Asian Monsoon
Robert Houze University of Washington (with
contributions from B. Smull)
Summer MONEX
Winter MONEX
Presented at International Conference on MONEX
and its Legacy, 3-7 Feb 2005, New Delhi
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Winter MONEX
Johnson Houze 1987
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WINTER MONEXDiurnal variation of high cloudiness
near Borneo
Bintulu
S. CHINA SEA
BORNEO
December 1978
08 LST
20 LST
14 LST
02 LST
Houze et al. 1981
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Radar Obs. of WINTER MONEX Borneo cloud system
Bintulu
Houze et al. 1981
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Diurnal gravity wave generation of mesoscale
convection over coastal South America
Mapes et al. 2003
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Summer MONEX
Johnson Houze 1987
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Percent High Cloudiness in the Summer
Monsoon May-September 1999
lt 235 K
lt 210 K
300 mb wind sfc pressure
850 mb wind
Zuidema 2002
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Diurnal cycle, mean percent high cloudiness, 1999
Cloud Top lt 210 K
Zuidema 2002
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Location of cloud systems by horizontal dimension
May-September 1999
CloudTop lt 210 K
Zuidema 2002
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JASMINE 1999
Webster et al. 2002
NOAA ShipRonald H. Brown
equator
60E
100E
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JASMINE Mesoscale Convective Systems Defined
tracked by 218 K infrared threshold
Zuidema 2002
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JASMINE 1999, Ship Track Satellite Data 85-90 E
Ship Track
Webster et al. 2002
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(No Transcript)
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IR Temperature
0830 LST
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IR Temperature
1130 LST
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IR Temperature
1430 LST
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IR Temperature
1730 LST
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IR Temperature
2030 LST
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IR Temperature
2030 LST
Ship radar
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JASMINE 1999 Ship Radar Data
2345 LST 22 May 99
0215 LST 23 May 99
0615 LST 23 May 99
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JASMINE 1999 Ship Radar Data
Reflectivity
Reflectivity
Doppler Radial Velocity
22 May 1999 2300 LST
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JASMINE 1999 Ship Radar Data
Reflectivity
Reflectivity
Doppler Radial Velocity
22 May 1999 2143 LST
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23 May 1999 0650 LST
JASMINE Ship RadarData
TRMM PrecipitationRadar Swath
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TRMM Precipitation Radar shows extensive
stratiform structure
23 May 1999 0650 LST
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SUMMER MONEX 6 July 1979
850 mb wind
Houze Churchill 1987
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Microphysics
SUMMER MONEX 6 July 1979 NOAA P3 Aircraft
20N
Radar
20N
14N
14N
88E
92E
88E
92E
Houze Churchill 1987
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SUMMER MONEX 8 July 1979
850 mb wind
Houze Churchill 1987
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Microphysics
SUMMER MONEX 8 July 1979 NOAA P3 Aircraft
20N
Radar
20N
16N
16N
82E
86E
82E
86E
Houze Churchill 1987
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SUMMER MONEX Microphysics, All P3 flights, 3-8
July 1979
-25
Columns
Plates Dendrites
Aggregates Drops
Columns
-20
Dendrites
-15
Flight Level Temperature (deg C)
-10


Plates
Aggregates
Needles
-5
0
Melting
Drops
Relative Frequency of Occurrence
Houze Churchill 1987
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TRMM Precipitation Radar June-Sept, 2002-2003
N
E
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Conclusions

• Oceanic convection in both winter and summer
  monsoons occur in deep, broad mesoscale
  convective systems, often diurnally forced
• Ground and airborne radars showed that
  precipitation in the mature mesoscale convective
  systems was predominantly stratiform
• Microphysical data collected by aircraft
  confirmed the highly stratiform character of the
  precipitation, with evidence of ice particle
  growth by vapor deposition aggregation
• JASMINE 1999 shows the deepest, broadest,
  longest lasting mesoscale systems are diurnal
  propagate southward, possibly as waves, with
  discrete jumps in the progression of the cloud
  systems
• TRMM satellite radar data (since 1997) confirm
  the stratiform character of the precipitation
  over the oceanin contrast to that over the land

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3rd MONEX Planning Meeting
New Delhi, February 1977
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MONEX 25
New Delhi, February 2005
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Diurnal cycle, mean percent high cloudiness, 1999
lt235 K
lt210 K
Zuidema 2002
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Stratiform precipitation shown by the Bintulu
Radar
Churchill Houze 1984
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WINTER MONEX Time series of high cloudiness seen
by satellite
SOUTH CHINA SEA
BORNEO
December 1978
Houze et al. 1981