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Retrieval and Application of Raindrop Size Retrieval and Application of Raindrop Size Distributions From Polarimetric Radar and Distributions From Polarimetric Radar and Disdrometer Data for Sub-synoptic Scale Disdrometer Data for Sub-synoptic Scale
Systems Systems
Retrieval and Application of Raindrop Size Retrieval and Application of Raindrop Size Distributions From Polarimetric Radar and Distributions From Polarimetric Radar and Disdrometer Data for Sub-synoptic Scale Disdrometer Data for Sub-synoptic Scale
Systems Systems
Petar BukovPetar Bukovčićčić1,3,41,3,4, Du, Dušan Zrnićšan Zrnić22,, Guifu ZhangGuifu Zhang3,43,4
1 1 Cooperative Institute for Mesoscale Meteorological Studies (CIMMS), University of Cooperative Institute for Mesoscale Meteorological Studies (CIMMS), University of Oklahoma, and NOAA/OAR National Severe Storms Laboratory, Norman, OKOklahoma, and NOAA/OAR National Severe Storms Laboratory, Norman, OK2 2 National Severe Storms Laboratory (NSSL), University of Oklahoma, Norman National Severe Storms Laboratory (NSSL), University of Oklahoma, Norman 3 3 School of Meteorology, University of Oklahoma, Norman, OK 73072School of Meteorology, University of Oklahoma, Norman, OK 730724 4 Atmospheric Radar Research Center (ARRC), University of Oklahoma, NormanAtmospheric Radar Research Center (ARRC), University of Oklahoma, Norman
Petar BukovPetar Bukovčićčić1,3,41,3,4, Du, Dušan Zrnićšan Zrnić22,, Guifu ZhangGuifu Zhang3,43,4
1 1 Cooperative Institute for Mesoscale Meteorological Studies (CIMMS), University of Cooperative Institute for Mesoscale Meteorological Studies (CIMMS), University of Oklahoma, and NOAA/OAR National Severe Storms Laboratory, Norman, OKOklahoma, and NOAA/OAR National Severe Storms Laboratory, Norman, OK2 2 National Severe Storms Laboratory (NSSL), University of Oklahoma, Norman National Severe Storms Laboratory (NSSL), University of Oklahoma, Norman 3 3 School of Meteorology, University of Oklahoma, Norman, OK 73072School of Meteorology, University of Oklahoma, Norman, OK 730724 4 Atmospheric Radar Research Center (ARRC), University of Oklahoma, NormanAtmospheric Radar Research Center (ARRC), University of Oklahoma, Norman
Croatian-USA Workshop on Mesometeorology, 19. Jun 2012, Eko park Kraš, Croatia
OverviewOverviewOverviewOverview
• IntroductionIntroduction• Instrumentation and datasetsInstrumentation and datasets
• Polarimetric KOUN radarPolarimetric KOUN radar• 2 Dimensional Video Disdrometers (2DVD)2 Dimensional Video Disdrometers (2DVD)• DatasetDataset
• Methodology – DSD retrievalsMethodology – DSD retrievals• Case studiesCase studies
• Squall line, July 13, 2005 Squall line, July 13, 2005 • Convective-stratiform mix, Jun 26, 2007Convective-stratiform mix, Jun 26, 2007• Convective rain, Jun 28, 2007Convective rain, Jun 28, 2007
• Summary and DiscussionSummary and Discussion
• IntroductionIntroduction• Instrumentation and datasetsInstrumentation and datasets
• Polarimetric KOUN radarPolarimetric KOUN radar• 2 Dimensional Video Disdrometers (2DVD)2 Dimensional Video Disdrometers (2DVD)• DatasetDataset
• Methodology – DSD retrievalsMethodology – DSD retrievals• Case studiesCase studies
• Squall line, July 13, 2005 Squall line, July 13, 2005 • Convective-stratiform mix, Jun 26, 2007Convective-stratiform mix, Jun 26, 2007• Convective rain, Jun 28, 2007Convective rain, Jun 28, 2007
• Summary and DiscussionSummary and Discussion
• Drop Size Distributions (DSDs)- contain essential Drop Size Distributions (DSDs)- contain essential information about precipitation microphysics information about precipitation microphysics
• Natural DSDs - high variabilityNatural DSDs - high variability• Three parameter modelThree parameter model
• Gamma DSD model: much closer to natural Gamma DSD model: much closer to natural DSDs, more flexible, 3 degrees of freedom DSDs, more flexible, 3 degrees of freedom (Ulbrich, 1983) (Ulbrich, 1983)
• μμ, , ΛΛ, N, N0 0 -- gamma DSD parameters gamma DSD parameters
• ZZHH,, ZZDRDR - radar measurements - radar measurements
• Drop Size Distributions (DSDs)- contain essential Drop Size Distributions (DSDs)- contain essential information about precipitation microphysics information about precipitation microphysics
• Natural DSDs - high variabilityNatural DSDs - high variability• Three parameter modelThree parameter model
• Gamma DSD model: much closer to natural Gamma DSD model: much closer to natural DSDs, more flexible, 3 degrees of freedom DSDs, more flexible, 3 degrees of freedom (Ulbrich, 1983) (Ulbrich, 1983)
• μμ, , ΛΛ, N, N0 0 -- gamma DSD parameters gamma DSD parameters
• ZZHH,, ZZDRDR - radar measurements - radar measurements
IntroductionIntroductionIntroductionIntroduction
IntroductionIntroductionIntroductionIntroduction
• 2 measurements - 3 parameters2 measurements - 3 parameters• Constraining relation neededConstraining relation needed
• Zhang (2001) proposed Zhang (2001) proposed μμ - - Λ Λ relationrelation• μμ andand ΛΛ highly correlated highly correlated
• DD00 and the shape of a rain drop spectrum are and the shape of a rain drop spectrum are
related → physical meaning of related → physical meaning of μμ – – ΛΛ
• Cao (2008) → unified Cao (2008) → unified μμ – –ΛΛ relation for relation for Oklahoma usedOklahoma used for both convective and for both convective and stratiform DSD retrievalsstratiform DSD retrievals
• 2 measurements - 3 parameters2 measurements - 3 parameters• Constraining relation neededConstraining relation needed
• Zhang (2001) proposed Zhang (2001) proposed μμ - - Λ Λ relationrelation• μμ andand ΛΛ highly correlated highly correlated
• DD00 and the shape of a rain drop spectrum are and the shape of a rain drop spectrum are
related → physical meaning of related → physical meaning of μμ – – ΛΛ
• Cao (2008) → unified Cao (2008) → unified μμ – –ΛΛ relation for relation for Oklahoma usedOklahoma used for both convective and for both convective and stratiform DSD retrievalsstratiform DSD retrievals
Instrumentation - KOUNInstrumentation - KOUNInstrumentation - KOUNInstrumentation - KOUN
• Polarimetric Radar: Polarimetric Radar: KOUN – Norman, OKKOUN – Norman, OK
• Provides info about Provides info about hydrometeor size, hydrometeor size, shape, phase, and shape, phase, and orientationorientation
• Allow retrieval of drop Allow retrieval of drop size distributions size distributions (DSDs)(DSDs)
• Polarimetric Radar: Polarimetric Radar: KOUN – Norman, OKKOUN – Norman, OK
• Provides info about Provides info about hydrometeor size, hydrometeor size, shape, phase, and shape, phase, and orientationorientation
• Allow retrieval of drop Allow retrieval of drop size distributions size distributions (DSDs)(DSDs)
Instrumentation – 2DVDInstrumentation – 2DVDInstrumentation – 2DVDInstrumentation – 2DVD• Joanneum Research Joanneum Research
2D Video Disdrometer 2D Video Disdrometer • low profile, OUlow profile, OU
• OU 2DVDs @ KFFL OU 2DVDs @ KFFL (Kessler’s Farm Field (Kessler’s Farm Field Laboratory)Laboratory)
• Joanneum Research Joanneum Research 2D Video Disdrometer 2D Video Disdrometer • low profile, OUlow profile, OU
• OU 2DVDs @ KFFL OU 2DVDs @ KFFL (Kessler’s Farm Field (Kessler’s Farm Field Laboratory)Laboratory)
OU 2DVDOU 2DVD
Instrumentation – 2DVDInstrumentation – 2DVDInstrumentation – 2DVDInstrumentation – 2DVD• Joanneum Research Joanneum Research
2D Video Disdrometer 2D Video Disdrometer • low profile, OUlow profile, OU
• OU 2DVDs @ KFFL OU 2DVDs @ KFFL (Kessler’s Farm Field (Kessler’s Farm Field Laboratory)Laboratory)
• Joanneum Research Joanneum Research 2D Video Disdrometer 2D Video Disdrometer • low profile, OUlow profile, OU
• OU 2DVDs @ KFFL OU 2DVDs @ KFFL (Kessler’s Farm Field (Kessler’s Farm Field Laboratory)Laboratory)
• 2DVD directly measures 2DVD directly measures the shape, size and the shape, size and falling velocity of falling velocity of precipitation particlesprecipitation particles
• 2DVD directly measures 2DVD directly measures the shape, size and the shape, size and falling velocity of falling velocity of precipitation particlesprecipitation particles
OU 2DVDOU 2DVD
Dataset – Data TypesDataset – Data TypesDataset – Data TypesDataset – Data Types
KOUNKOUNKOUNKOUN 2DVD2DVD2DVD2DVD
• Disdrometer Data Disdrometer Data • DSDs - dropsize distributions DSDs - dropsize distributions
R R - rainfall- rainfall rate rate DD00 - - median volume diameter median volume diameter
• Disdrometer Data Disdrometer Data • DSDs - dropsize distributions DSDs - dropsize distributions
R R - rainfall- rainfall rate rate DD00 - - median volume diameter median volume diameter
• Radar Data Radar Data • ZZHH - horizontal reflectivity - horizontal reflectivity
ZZDRDR - differential reflectivity - differential reflectivity ρρhvhv - correlation coefficient - correlation coefficient
• Radar Data Radar Data • ZZHH - horizontal reflectivity - horizontal reflectivity
ZZDRDR - differential reflectivity - differential reflectivity ρρhvhv - correlation coefficient - correlation coefficient
• Gamma DSDGamma DSD
• NN((DD) ) - DSD- DSD• NN00 ((mmmm-1- -1- μμ m m-3-3) ) - number concentration parameter- number concentration parameter
• μμ - - the shape distribution parameter the shape distribution parameter• ΛΛ ((mmmm-1-1) ) -- the slope parameter the slope parameter
• DD ((mmmm) ) - - the equivalent volume diameterthe equivalent volume diameter • Constraining relation for OK rain (Cao et al. 2008)Constraining relation for OK rain (Cao et al. 2008)
• Gamma DSDGamma DSD
• NN((DD) ) - DSD- DSD• NN00 ((mmmm-1- -1- μμ m m-3-3) ) - number concentration parameter- number concentration parameter
• μμ - - the shape distribution parameter the shape distribution parameter• ΛΛ ((mmmm-1-1) ) -- the slope parameter the slope parameter
• DD ((mmmm) ) - - the equivalent volume diameterthe equivalent volume diameter • Constraining relation for OK rain (Cao et al. 2008)Constraining relation for OK rain (Cao et al. 2008)
0 expN D N D D
20.0201 0.902 1.718
Methodology – DSD retrievalsMethodology – DSD retrievalsMethodology – DSD retrievalsMethodology – DSD retrievals
• ZZDRDR and and μμ--ΛΛ relationship to find two parameters relationship to find two parameters
• ZZHH to find to find NN00
• ΛΛ,, μμ andand NN00 → → NN((DD) ) → → R,R, DD0 0 (DSD parameters)(DSD parameters)
• ZZDRDR and and μμ--ΛΛ relationship to find two parameters relationship to find two parameters
• ZZHH to find to find NN00
• ΛΛ,, μμ andand NN00 → → NN((DD) ) → → R,R, DD0 0 (DSD parameters)(DSD parameters)
0
3.67D
0
0
3 3
0
D
DD N D dD D N D dD
4 3
1
6 10L
i i ii
R D v D N D D
2 3 40.1021 4.932 0.9551 0.07934 0.002362i i i i iv D D D D D
mm
/mm hr
/m s
Methodology – DSD retrievalsMethodology – DSD retrievalsMethodology – DSD retrievalsMethodology – DSD retrievals
Case StudiesCase StudiesCase StudiesCase Studies
• Several types of storms:Several types of storms: > > Squall line, July 13, 2007;Squall line, July 13, 2007; > > Convective-stratiform mix, June 26, 2007;Convective-stratiform mix, June 26, 2007; > > Convective rain, June 28, 2007;Convective rain, June 28, 2007;
• Several types of storms:Several types of storms: > > Squall line, July 13, 2007;Squall line, July 13, 2007; > > Convective-stratiform mix, June 26, 2007;Convective-stratiform mix, June 26, 2007; > > Convective rain, June 28, 2007;Convective rain, June 28, 2007;
Squall line, May 13, 2005Squall line, May 13, 2005
0730 UTC0730 UTC0730 UTC0730 UTC
ZZDRDRZZDRDRZZHHZZHH
ρρhvhvρρhvhv class.class.class.class.
KOUNKOUNKOUNKOUN
Squall line, May 13, 2005Squall line, May 13, 2005
N(D)N(D)N(D)N(D)
m(D)m(D)m(D)m(D)
Z(D)Z(D)Z(D)Z(D)
ZZDRDR(D)(D)ZZDRDR(D)(D)
2DVD2DVD2DVD2DVD
Squall line, May 13, 2005Squall line, May 13, 2005
ZZHHZZHH
ZZDRDRZZDRDR
ρρhvhvρρhvhv
KOUN – vertical profile over 2DVD locationKOUN – vertical profile over 2DVD locationKOUN – vertical profile over 2DVD locationKOUN – vertical profile over 2DVD location
Squall line, May 13, 2005Squall line, May 13, 2005
Comparison - retrievals, KOUN vs. 2DVDComparison - retrievals, KOUN vs. 2DVDComparison - retrievals, KOUN vs. 2DVDComparison - retrievals, KOUN vs. 2DVD
RRRR
DD00DD00
ZZHHZZHH
ZZDRDRZZDRDR
1200 UTC1200 UTC1200 UTC1200 UTC
ZZDRDRZZDRDRZZHHZZHH
ρρhvhvρρhvhv class.class.class.class.
KOUNKOUNKOUNKOUN
Convective-stratiform mix, June 26, 2007Convective-stratiform mix, June 26, 2007
2DVD2DVD2DVD2DVD
N(D)N(D)N(D)N(D)
m(D)m(D)m(D)m(D)
Z(D)Z(D)Z(D)Z(D)
ZZDRDR(D)(D)ZZDRDR(D)(D)
Convective-stratiform mix, June 26, 2007Convective-stratiform mix, June 26, 2007
ZZHHZZHH
ZZDRDRZZDRDR
ρρhvhvρρhvhv
KOUN – vertical profile over 2DVD locationKOUN – vertical profile over 2DVD locationKOUN – vertical profile over 2DVD locationKOUN – vertical profile over 2DVD location
Convective-stratiform mix, June 26, 2007Convective-stratiform mix, June 26, 2007
Convective-stratiform mix, June 26, 2007Convective-stratiform mix, June 26, 2007
ZZHHZZHH RRRR
DD00DD00ZZDRDRZZDRDR
Comparison - retrievals, KOUN vs. 2DVDComparison - retrievals, KOUN vs. 2DVDComparison - retrievals, KOUN vs. 2DVDComparison - retrievals, KOUN vs. 2DVD
Convective rain, June 28, 2007Convective rain, June 28, 2007
1230 UTC1230 UTC1230 UTC1230 UTC
ZZDRDRZZDRDRZZHHZZHH
ρρhvhvρρhvhv class.class.class.class.
KOUNKOUNKOUNKOUN
Convective rain, June 28, 2007Convective rain, June 28, 2007
N(D)N(D)N(D)N(D)
m(D)m(D)m(D)m(D)
Z(D)Z(D)Z(D)Z(D)
ZZDRDR(D)(D)ZZDRDR(D)(D)
2DVD2DVD2DVD2DVD
Convective rain, June 28, 2007Convective rain, June 28, 2007
ZZHHZZHH
ZZDRDRZZDRDR
ρρhvhvρρhvhv
KOUN – vertical profile over 2DVD locationKOUN – vertical profile over 2DVD locationKOUN – vertical profile over 2DVD locationKOUN – vertical profile over 2DVD location
Convective rain, June 28, 2007Convective rain, June 28, 2007
ZZHHZZHH RRRR
DD00DD00ZZDRDRZZDRDR
Comparison - retrievals, KOUN vs. 2DVDComparison - retrievals, KOUN vs. 2DVDComparison - retrievals, KOUN vs. 2DVDComparison - retrievals, KOUN vs. 2DVD
• Radar data and disdrometer measurements Radar data and disdrometer measurements generally agree well for sub-synoptic scale systemsgenerally agree well for sub-synoptic scale systems
• Radar retrieved Radar retrieved RR is in good agreement with 2DVD is in good agreement with 2DVD and not too sensitive if and not too sensitive if μμ – –Λ Λ changes changes
• DD0 0 →→ highly sensitive if highly sensitive if μμ – –ΛΛ changeschanges
• Radar retrieved Radar retrieved DD00 →→ slightly lower in stratiform and slightly lower in stratiform and
higher in convective stages of the storm compared higher in convective stages of the storm compared to 2DVD, but trends match very wellto 2DVD, but trends match very well
• Convective and stratiform storm stages should be treated separately
• Radar data and disdrometer measurements Radar data and disdrometer measurements generally agree well for sub-synoptic scale systemsgenerally agree well for sub-synoptic scale systems
• Radar retrieved Radar retrieved RR is in good agreement with 2DVD is in good agreement with 2DVD and not too sensitive if and not too sensitive if μμ – –Λ Λ changes changes
• DD0 0 →→ highly sensitive if highly sensitive if μμ – –ΛΛ changeschanges
• Radar retrieved Radar retrieved DD00 →→ slightly lower in stratiform and slightly lower in stratiform and
higher in convective stages of the storm compared higher in convective stages of the storm compared to 2DVD, but trends match very wellto 2DVD, but trends match very well
• Convective and stratiform storm stages should be treated separately
Summary and DiscussionSummary and DiscussionSummary and DiscussionSummary and Discussion
Summary and DiscussionSummary and DiscussionSummary and DiscussionSummary and Discussion
• Reliable DSD retrieval technique is essential for Reliable DSD retrieval technique is essential for accurate rain estimation and model parameterizationaccurate rain estimation and model parameterization
• Future workFuture work• Implementation of polarimetric radar data into NWP Implementation of polarimetric radar data into NWP
modelsmodels• Link between dynamics and microphysics (dual Doppler Link between dynamics and microphysics (dual Doppler
analysis)analysis)• μμ - - ΛΛ adjustment (big drops, long tail DSDs)adjustment (big drops, long tail DSDs)• Separation of convective and stratiform stages Separation of convective and stratiform stages
• Reliable DSD retrieval technique is essential for Reliable DSD retrieval technique is essential for accurate rain estimation and model parameterizationaccurate rain estimation and model parameterization
• Future workFuture work• Implementation of polarimetric radar data into NWP Implementation of polarimetric radar data into NWP
modelsmodels• Link between dynamics and microphysics (dual Doppler Link between dynamics and microphysics (dual Doppler
analysis)analysis)• μμ - - ΛΛ adjustment (big drops, long tail DSDs)adjustment (big drops, long tail DSDs)• Separation of convective and stratiform stages Separation of convective and stratiform stages
Thank you!Thank you!Thank you!Thank you!
Questions?Questions?Questions?Questions?
petar.bukovcic@ou.edupetar.bukovcic@ou.edu
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