numerical prediction of high-impact local weather: how good can it get? kelvin k. droegemeier...
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Numerical Prediction of Numerical Prediction of High-Impact Local High-Impact Local
Weather: Weather: How Good Can It Get?How Good Can It Get?
Kelvin K. DroegemeierKelvin K. DroegemeierRegents’ Professor of MeteorologyRegents’ Professor of Meteorology
Vice President for ResearchVice President for ResearchUniversity of OklahomaUniversity of Oklahoma
2013 Congress2013 Congress19 April 201319 April 2013
Agriculture Agriculture $135.8B (100%)$135.8B (100%) Oil and Gas Extraction Oil and Gas Extraction $99.5B (100%)$99.5B (100%) Construction Construction $463.6B (100%)$463.6B (100%) Transportation Transportation $786.5B ( 95%)$786.5B ( 95%) Retail Trade Retail Trade $893.9B (100%)$893.9B (100%) State/Local Government State/Local Government $829.5B (100%)$829.5B (100%) OthersOthers
TotalTotal $3.86T ( 40%)$3.86T ( 40%)
40%40% of the $10T U.S. Economy of the $10T U.S. Economy is Impacted by Weather and is Impacted by Weather and
ClimateClimate
876876 deaths annually due to severe deaths annually due to severe weatherweather
7000+7000+ weather-related traffic fatalities weather-related traffic fatalities 450,000450,000 weather-related traffic injuries weather-related traffic injuries
A Great Toll in Human A Great Toll in Human LifeLife
About About 50%50% of the loss is of the loss is deemed preventable with deemed preventable with
better weather and climate better weather and climate forecasts!forecasts!
Copyright © 2003 WGN-TV
Computer ModelsComputer Models are the Primary Source are the Primary Source of Information for All Weather & Climate of Information for All Weather & Climate
PredictionsPredictions
The Prediction ProcessThe Prediction Process
Analyze ResultsAnalyze Results
Com
pare
and
Ver
ify
Com
pare
and
Ver
ify
Observe the AtmosphereObserve the Atmosphere
Identify and ApplyIdentify and ApplyPhysical LawsPhysical Laws
Create a MathematicalCreate a MathematicalModelModel
Create and Run aCreate and Run aComputer ModelComputer Model
Data Assimilation Data Assimilation
D
ata
Ass
imil
atio
n S
yste
m
RadarsRadars Radial Wind, Reflectivity
Other ObservationsOther Observations A Bit of Everything Some Places
ForecastForecastModel OutputModel Output
All Variables, But From a Forecast
3D Gridded AnalysisThat Contains allVariables, is DynamicallyConsistent, and has Minimum Global Error w/r/t theObservations
The First Numerical Weather Prediction The First Numerical Weather Prediction ExperimentExperiment
Done on ENIAC: 5 Done on ENIAC: 5 million times slower million times slower than my laptopthan my laptop
Numerically integrated Numerically integrated oneone equation at equation at oneone altitudealtitude
450 mile grid spacing450 mile grid spacing 24 hour forecast took 24 hour forecast took
24 hours24 hours
Today’s ModelsToday’s Models
Typical Forecast from Today’s Typical Forecast from Today’s Operational ModelsOperational Models
What Causes the Major What Causes the Major Problems?Problems?
A Foundational QuestionA Foundational Question
. . . explicitly predict this. . . explicitly predict thistype of weather?type of weather?
Can computer forecastCan computer forecasttechnology. . .technology. . .
Example : March 28, 2000 Fort Example : March 28, 2000 Fort Worth Tornadic StormsWorth Tornadic Storms
Tornado
Local TV Station RadarLocal TV Station Radar
NWS NWS 12-hr12-hr Computer Forecast Valid at 6 pm CDT Computer Forecast Valid at 6 pm CDT (near tornado time)(near tornado time)
No Explicit Evidence of Precipitation in North TexasNo Explicit Evidence of Precipitation in North Texas
Reality Was Quite Reality Was Quite Different!Different!
6 pm 7 pm 8 pmR
adar
Xue et al. (2003)
Fort Worth
Hourly Radar Observations(Fort Worth Shown by the Pink Star)
6 pm 7 pm 8 pmR
adar
Fcs
t Wit
h R
adar
Dat
a
2 hr 3 hr 4 hr
Fort Worth
Fort Worth
Xue et al. (2003)
How Good Are the How Good Are the Forecasts??Forecasts??
Actual Event
30 miles
D/FW Airport
A perfectly predicted storm having a position error A perfectly predicted storm having a position error of 30 miles may be a terrible forecast on the scale of 30 miles may be a terrible forecast on the scale of a single airportof a single airport
Forecast
O
F
50 km
One Forecast Verification One Forecast Verification StrategyStrategy
HIT
O
F
50 km
MISS
O
F30 km
HIT
O
F
MISS
30 km
One Forecast Verification One Forecast Verification StrategyStrategy
0.6
0.7
0.8
0.9
1
1.1
2230Z 2300Z 2330Z 0000Z
May 3 ARPS Forecast with WSR-88D Level II DataInitialized 22 UTC Using 3 km Spatial Resolution
Verification Within Circles of Radii Indicated(VIP Level 3)
POD (50 km)POD (40 km)POD (30 km)POD (20 km)POD (10 km)
Time (UTC)
Probability of DetectionProbability of Detection
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
2230Z 2300Z 2330Z 0000Z
May 3 ARPS Forecast with WSR-88D Level II DataInitialized 22 UTC Using 3 km Spatial Resolution
Verification Within Circles of Radii Indicated(VIP Level 3)
PFA (50 km)PFA (40 km)PFA (30 km)PFA (20 km)PFA (10 km)
Time (UTC)
False Alarm RateFalse Alarm Rate
Actual Event
30 miles
D/FW Airport
We need to forecast the weather PLUS We need to forecast the weather PLUS the accuracy of the forecast!!!the accuracy of the forecast!!!
Forecast
As a Forecaster As a Forecaster Worried About Worried About This Reality… This Reality…
7 pm
As a Forecaster As a Forecaster Worried About Worried About This Reality… This Reality…
How Much How Much Trust Would Trust Would You Place in You Place in This Model This Model Forecast? Forecast?
3 hr
7 pm
Initial State Uncertainty
Truth
Single Forecast
Traditional Forecasting
Methodology
t critical
Deterministic Forecast
Probabilistic Forecast
Ensemble Forecasting
Initial State Uncertainty
Mean
Truth
Actual RadarActual Radar
Forecast #1Forecast #1 Forecast #2Forecast #2
Forecast #3Forecast #3 Forecast #5Forecast #5Forecast #4Forecast #4
Actual RadarActual Radar
Probability of Intense PrecipitationProbability of Intense Precipitation
Model Forecast Radar Observations
MUCH MORE Computing Power is MUCH MORE Computing Power is Required!!Required!!
Each set of forecasts (ensemble and individual)Each set of forecasts (ensemble and individual)– produces 6 TB of output PER DAYproduces 6 TB of output PER DAY– Requires 9000 cores (750 nodes) of the Kraken Cray XT5 at Oak RidgeRequires 9000 cores (750 nodes) of the Kraken Cray XT5 at Oak Ridge– Takes 6.5 hours to runTakes 6.5 hours to run
Provisioning of data in real timeProvisioning of data in real time Management in a repository – retention time?Management in a repository – retention time? Experiment reproducibility!!Experiment reproducibility!! Creating products that will benefit the public (smart device location-Creating products that will benefit the public (smart device location-
based warnings)based warnings)
ChallengesChallenges
A Fundamental Research A Fundamental Research QuestionQuestion
Can we better understand the atmosphere, Can we better understand the atmosphere, educate more effectively about it, and forecast educate more effectively about it, and forecast more accurately if we more accurately if we adaptadapt our technologies and our technologies and approaches to the weather approaches to the weather as it occursas it occurs??
People, even animals adapt/respond: Why don’t People, even animals adapt/respond: Why don’t our resources???our resources???
The VisionThe VisionRevolutionize the ability of scientists, students, Revolutionize the ability of scientists, students,
and operational practitioners to observe, and operational practitioners to observe, analyze, predict, understand, and respond to analyze, predict, understand, and respond to intense local weather by interacting with it intense local weather by interacting with it
dynamically and adaptivelydynamically and adaptively in real time in real time
The Value of Adaptation: Forecaster-The Value of Adaptation: Forecaster-Initiated PredictionsInitiated Predictions
Brewster et al. (2008)
Observed Composite Reflectivity
20 hr Pre-ScheduledWRF-ARF
5 hr LEAD Dynamic WRF-ARF With RadarData Assimilation
The Million Dollar The Million Dollar Question: Will Question: Will
Computer Models Ever Computer Models Ever Be Able to Be Able to PredictPredict
Tornadoes?Tornadoes?
24 May 2011 Tornado Outbreak: 24 May 2011 Tornado Outbreak: Warning on a Numerical ForecastWarning on a Numerical Forecast
NWS OUN Graphic
24 May 2011 Tornado Outbreak: 24 May 2011 Tornado Outbreak: Warning on a Numerical ForecastWarning on a Numerical Forecast
Are All the Data Making Are All the Data Making a Difference?a Difference?
44
45
Are All the Data Making Are All the Data Making a Difference?a Difference?
Numerical Simulation24 hours CPU = 1 hour real20 TB of outputStill trying to understand
Mother NatureReal time!Still trying to understand
Data Don’t Guarantee Data Don’t Guarantee Understanding!Understanding!
Be careful what you wish for! A one-hour model-based “tornado Be careful what you wish for! A one-hour model-based “tornado warning” would be a game changerwarning” would be a game changer
Social and behavioral science elements are criticalSocial and behavioral science elements are critical– Why did 550 people die in the US last year from tornadoes?Why did 550 people die in the US last year from tornadoes?
Our ability to effectively warn the public and understand its Our ability to effectively warn the public and understand its response is relatively cruderesponse is relatively crude
This is an area ripe for additional research – and it is ESSENTIAL This is an area ripe for additional research – and it is ESSENTIAL for making progressfor making progress
ChallengesChallenges
TODAY: Centralized TODAY: Centralized Prediction, Distributed DataPrediction, Distributed Data
TOMORROW: Distributed & Cloud-TOMORROW: Distributed & Cloud-Based Models Run Locally, On Based Models Run Locally, On
DemandDemand
10 km
3 km
3 km
3 km3 km
10 km
20 km CONUS Ensembles