Maurice Blackmon’s Influence on a Weather Forecaster and Weather Forecasting

Maurice Blackmon’s Influence on a Weather Forecaster and Weather Forecasting

Steven L. MullenUniversity of Arizona

(Sabbatical at NOAA/ESRL/GSD)

(and Weather Forecasting)

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Great deal available for game 5 tonight!

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Duel MLB venues!

It’s a MLB Weekend!

“Weather” by Land…

Or by Sea…

It Did Not Matter

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The Boy Loved Weather!

But Forecaster Needed Rigor

€

ddte−t( ) = −te

−t−1

Work hard Forecaster. With total dedication and superb guidance,

there is a way.

http://mathmistakes.info/mistakes/calculus/http://en.wikipedia.org/wiki/Gottfried_Leibniz

Forecaster Was Very Fortunate

• He was introduced to man who wasWiseKind

PatientForgiving

GivingQuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.

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Example Blocking Event

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Blackmon et al. (1985 JAS)

See What GCM’s Now Simulate

• Height Anomalies in NCAR CCM0

• Would you consider coming to NCAR to do a dissertation on blocking in CCM0 under my guidance?

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Blackmon et al. (1985 JAS)

Persistent Anomalies (+100m, 10 days)

Blackmon et al. (1985 JAS)

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Model CCM1

Blocking Onset

Blackmon et al. (1985 JAS)

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Low PV

Low PV

Blocking Onset

Blackmon et al. (1985 JAS)

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Low PV

Low PV

Block Maintenance

Blackmon et al. (1985 JAS)

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Blackmon et al. (1985 JAS)

Synoptic Eddy Forcing of Blocks

• Onset preceded by rapid cyclogenesis; attendant poleward flux of low PV air

• Maintenance phase N-S elongated eddies that weaken as they approach block; EW elongated eddies on east side of block

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Blackmon et al. (1985 JAS)

GCM Blocking

• “We conclude that the blocking episodes produced in the model are quite realistic and we believe that the model data can be used as a reasonable proxy for observations to study this phenomenon.”

Synoptic Eddy Forcing of Blocks

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QG Height Tendency at 300 mb and 1000 mb during Atlantic Blocking Episodes

CCM0 Output

Mullen 1987

Synoptic Eddy Forcing of Blocks

QG Height Tendency at 300 mb and 1000 mb during Atlantic Blocking Episodes

NMC Analyses

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Mullen 1987

Ratio of Barotropic Deformation to

Baroclinic Growth Parameter

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Black and Dole (2000)

NCEP

CCM2

CCM3

GCM’s, SST and “Blocking”

Mullen (1989 JC)

• NCAR CCM0 forcing by the 1976/77 SST anomaly of Blackmon et al. (1983) and Pitcher et al. (1988)

• How much does “blocking” contribute to time-mean flow anomalies?

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GCM’s, SST’s and “Blocking”

Mullen (1989 JC)

• 500 mb height anomaly for all 1,200 simulation days.

• Half the size

• 500 mb height anomaly for the ~90% of days that did not exhibit a “block”

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Blocking Predictability

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Nutter et al (1998)

PQPF Ensemble Forecasts

• Two ensemble members for 6-12 h precipitation forecasts from the MM4 Modeling system.

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Du et al. (1997)

DFW Grid Point for 2004 Spring Project

ARW 12kmMore

anistropic Slower motion

Eta 12kmMore

isotropic Faster motion

Stage4 12km

Stage4 12km

Lag -3h

Lag 0h

Lag +3h

Probabilistic prediction in AWIPS II

Local database

SREF NAEFS ECMWF

Probabilistic guidance from NCEP

Probability generator / calibrator

NDFD

GFE

Climo Verification

Courtesy Paul Schultz

What I remember most…

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