Oceanic Convection Diagnosis and Nowcasting
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Transcript of Oceanic Convection Diagnosis and Nowcasting
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Oceanic Convection Diagnosis and NowcastingOceanic Convection Diagnosis and Nowcasting
Cathy Kessinger, Cindy Mueller, Huaqing Cai, Cathy Kessinger, Cindy Mueller, Huaqing Cai, Gary Blackburn, Nancy Rehak, Kay Levesque, Gary Blackburn, Nancy Rehak, Kay Levesque, Ben Hendrickson, Steve Carson, Dan MegenhardtBen Hendrickson, Steve Carson, Dan Megenhardt
ICMCS-V Conference - October 31, 2006
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Oceanic Convection Diagnosis and Nowcasting
• Federal Aviation Administration (FAA) and National Aeronautics and Space Administration (NASA) sponsors– Oceanic aviation community– Collaboration with Naval Research Laboratory and
Massachusetts Institute of Technology Lincoln Laboratory
• Developing oceanic diagnosis and nowcasting products– Few derived products available for oceanic aviation
• Convective Diagnosis Oceanic (CDO)– GOES-based detection of convection– Fuzzy logic combination of 3 algorithms:
• CTOP: NRL Cloud top height• CldClass: NRL Cloud classification• GCD: Global Convective Diagnosis
• Convective Nowcast Oceanic (CNO)– Extrapolation of CDO using an object tracker– 0-2 hour nowcasts now; longer term nowcasts/forecasts later
• Gulf of Mexico domain - extend to Pacific domain soon
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NRL Cloud Top Height (CTOP)
• Cloud IR temperature converted to heights– Global Forecast System (GFS) model sounding
• Temperature matched to pressure level
• Pressure level converted to height via Standard Atmosphere
– Works best with opaque clouds
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NRL Cloud Classification (CldClass)• Discriminates cloud types
– Compares derived fields from current image to those “truthed” by experts to get best match
• Daytime and nighttime versions combined– Nighttime less precise due to loss of visible channel
Daytime:15 Categories
Nighttime:10 Categories
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Global Convective Diagnostic (GCD)
• Uses channel differencing (gvar_ch3 - gvar_ch4)• Differences near zero are significant
– Indicates updraft region
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Fuzzy logic methodology
• Inputs are scaled between 0-1• Weighted summation calculated• Threshold applied to define CDO
INPUT
CTOPCloudClassGCD
Apply membership
functions
FUZZY LOGIC ENGINE
T Convective DiagnosisOceanic
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w
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w
Apply weights
wf
ComputeInterestField
ApplyThreshold
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CDO Membership Functions
Weight = 1Weight = 1
Weight = 2
-10 -5 -1 25 30 (delta BTemperature)
1
0
GCD
0 20 40 80(Kft)
1
0
CTOP
1
0
CldClass Daytime
0.5
CldClass Nighttime
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Future: Add number of lightning strikes as a
feature field and specialized POES fields
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CTOP
Cloud Classifier
Visible & IR
GCD
CDO
Gulf of Mexico from 4 June 2006 at 2215 UTC
CDO
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CDO with threshold applied
Visible & IR
Gulf of Mexico from 4 June 2006 at 2215 UTC
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CDO Comparison to NEXRAD Reflectivity
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Convective Nowcast Oceanic (CNO)
• Methodology:– Extrapolate the CDO
• TITAN – object tracker for storm motion vector
– Use Global Forecast System (GFS) model • Frontal likelihood and stability analysis (from NCWF2,6)
– Additional fields to be added (work in progress)• Sea surface temperature
– Warm water = deep storms; Cold water = no/shallow storms
• QuikSCAT scatterometer near-surface winds– Updated twice/day and shows near-surface convergence
• Sounder: Temperature/moisture vertical profiles – Stability analysis
• TRMM lightning climatology
• Merge satellite-tracked winds with GFS to improve wind field– Returns mesocale features
• TRMM PR and CloudSat CR to verify storms
• Collecting the necessary pieces ; now put them together
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• Polar orbiter data:– Sea surface temperature– QuikScat winds
• Near-sfc convergence
CNO Work in Progress
SST
Cloud TopHeight QuikScat
Divergence
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Nowcast Design Concept
VisIR
CTOPCClassGCDLtg
CDO-detect
CDO-extrap(GFS winds +
sat-trackedwinds)
Decay
1. SST < 26 deg C2. No QuikSCAT near-sfc convergence3. Stable conditions
a. Sounderb. GFS
Growth
1. SST > 26 deg C2. QuikSCAT near-surface convergence3. Unstable/neutral conditions
a. Sounderb. GFS
ObjectTracker
forStorms
Used to modify storm shapes
TRMM Verification
TRMM Lightning
Climatology
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Visible
Summary
• Methodology for the Convective Diagnosis Oceanic• Design for 0-2 hr Oceanic Nowcasting• Preliminary results shown below for 1 hr and 2 hr
IR 1hr CNO2hr CNO
IR 1hr CNO
Verification
IR 2hr CNO
Verification
Thank you!