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

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

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

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

Global Convective Diagnostic (GCD)

• Uses channel differencing (gvar_ch3 - gvar_ch4)• Differences near zero are significant

– Indicates updraft region

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

w

w

w

w

Apply weights

wf

ComputeInterestField

ApplyThreshold

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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ixed

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ow

Missin

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un G

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imbu

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ong

estus

Cirro

stratus

Cirro

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irrus

Altostra

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ulu

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lusS

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tratu

s

Future: Add number of lightning strikes as a

feature field and specialized POES fields

CTOP

Cloud Classifier

Visible & IR

GCD

CDO

Gulf of Mexico from 4 June 2006 at 2215 UTC

CDO

CDO with threshold applied

Visible & IR

Gulf of Mexico from 4 June 2006 at 2215 UTC

CDO Comparison to NEXRAD Reflectivity

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

• Polar orbiter data:– Sea surface temperature– QuikScat winds

• Near-sfc convergence

CNO Work in Progress

SST

Cloud TopHeight QuikScat

Divergence

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

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!