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Transcript of Kelvin K. Droegemeier School of Meteorology Center for Analysis and Prediction of Storms University...
Kelvin K. DroegemeierKelvin K. DroegemeierSchool of Meteorology School of Meteorology
Center for Analysis and Prediction of StormsCenter for Analysis and Prediction of StormsUniversity of OklahomaUniversity of Oklahoma
National Press Foundation Program “Understanding Violent National Press Foundation Program “Understanding Violent Weather”Weather”
26 October 200526 October 2005
Advances in the Advances in the Observation and Observation and
Computer Prediction of Computer Prediction of Severe StormsSevere Storms
Copyright © 2003 WGN-TV
Everyone is Familiar With This Everyone is Familiar With This Person!!Person!!
Copyright © 2003 WGN-TV
Computer ModelsComputer Models are the Primary Source are the Primary Source of Information for All Weather Forecastsof Information for All Weather Forecasts
Numerical Weather Numerical Weather PredictionPrediction
The use of computer models The use of computer models of the atmosphere toof the atmosphere to
predictpredict the weather given a the weather given a set of current observationsset of current observations
According to Webster…According to Webster…
pre·dictpre·dict: To state, tell about, or : To state, tell about, or make known in advance, especially make known in advance, especially on the basis of special knowledge.on the basis of special knowledge.
According to According to Meteorologists…Meteorologists…
pre·dictpre·dict: To state, tell about, or : To state, tell about, or make known in advance, trying not make known in advance, trying not to lie and always keeping the coin to lie and always keeping the coin concealed from curious onlookers.concealed from curious onlookers.
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
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
Observe the Atmosphere Observe the Atmosphere
Upper-AirUpper-AirBalloonsBalloons
SatellitesSatellites
NEXRAD NEXRAD Doppler Doppler
RadarRadar
Commercial AircraftCommercial Aircraft
AutomatedAutomatedSurface Surface
NetworksNetworks
The Prediction ProcessThe Prediction Process
Analyze ResultsAnalyze Results
Com
pare
and
Ver
ify
Com
pare
and
Ver
ify Identify and ApplyIdentify and Apply
Physical LawsPhysical Laws
Create a MathematicalCreate a MathematicalModelModel
Create and Run aCreate and Run aComputer ModelComputer Model
Observe the AtmosphereObserve the Atmosphere
Identify & Apply Physical Identify & Apply Physical LawsLaws
F=ma
The Prediction ProcessThe Prediction Process
Analyze ResultsAnalyze Results
Com
pare
and
Ver
ify
Com
pare
and
Ver
ify
Create a MathematicalCreate a MathematicalModelModel
Create and Run aCreate and Run aComputer ModelComputer Model
Observe the AtmosphereObserve the Atmosphere
Identify and ApplyIdentify and ApplyPhysical LawsPhysical Laws
Create a Mathematical ModelCreate a Mathematical Model
The Prediction ProcessThe Prediction Process
Analyze ResultsAnalyze Results
Com
pare
and
Ver
ify
Com
pare
and
Ver
ify
Create and Run aCreate and Run aComputer ModelComputer Model
Observe the AtmosphereObserve the Atmosphere
Identify and ApplyIdentify and ApplyPhysical LawsPhysical Laws
Create a MathematicalCreate a MathematicalModelModel
Create Computer Model Create Computer Model
Create Computer Model Create Computer Model
Solve highly nonlinear partial differential equations Solve highly nonlinear partial differential equations East/West WindEast/West Wind North/South WindNorth/South Wind Vertical WindVertical Wind TemperatureTemperature Water VaporWater Vapor Cloud WaterCloud Water Precipitating WaterPrecipitating Water Cloud IceCloud Ice GraupelGraupel HailHail Surface TemperatureSurface Temperature Surface MoistureSurface Moisture Soil TemperatureSoil Temperature Soil MoistureSoil Moisture Sub-Grid TurbulenceSub-Grid Turbulence
Run the Computer Model Run the Computer Model
Over the course of a single forecast, the Over the course of a single forecast, the computercomputermodel solves billions of model solves billions of equationsequations
Requires the fastest Requires the fastest supercomputers in the supercomputers in the world -- capable ofworld -- capable ofperforming trillions of performing trillions of calculationscalculationseach secondeach second
Run the Computer Model Run the Computer Model
Finer resolution allows the model to capture Finer resolution allows the model to capture more detailmore detail
Requires more computer power Requires more computer power – doubling the number of grid boxes in 3-D increases the doubling the number of grid boxes in 3-D increases the
computer requirements by a factor of 16! computer requirements by a factor of 16!
More Power!!! More Power!!!
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
Analyze the Analyze the Results/Compare/Verify Results/Compare/Verify
In the Beginning… ENIACIn the Beginning… ENIAC
ENIAC Versus TodayENIAC Versus Today
Weighed 30 tonsWeighed 30 tons Had 18,000 vacuum tubes, 1,500 Had 18,000 vacuum tubes, 1,500
relays thousands of resistors, relays thousands of resistors, capacitors, inductorscapacitors, inductors
Peak speed of 5000 adds/second Peak speed of 5000 adds/second and 300 multiplies/secand 300 multiplies/sec
A 1.2 GHz Pentium IV processor is A 1.2 GHz Pentium IV processor is 500,000 times faster than the 500,000 times faster than the ENIACENIAC
A desktop PC with 1 Gbyte of RAM A desktop PC with 1 Gbyte of RAM can store 5 million times as much can store 5 million times as much data as the ENIAC data as the ENIAC
1950: The First Computer Weather 1950: The First Computer Weather Forecast ModelForecast Model
450 Miles
Today’s ModelsToday’s Models
A Typical Forecast From Today’s A Typical Forecast From Today’s ModelsModels
What Causes the Major What Causes the Major Problems?Problems?
Why the Lack of Detail in the Why the Lack of Detail in the Model? Model?
This ThunderstormFalls Through the Cracks
Why the Lack of Detail in the Why the Lack of Detail in the Model? Model?
A Foundational QuestionA Foundational Question
Can computer forecastCan computer forecasttechnology. . .technology. . .
. . . explicitly predict this. . . explicitly predict thistype of weather?type of weather?
Would This Capability Be Would This Capability Be Useful?Useful?
Intense local weather causes economic losses in the Intense local weather causes economic losses in the US that average US that average $300 M$300 M per weekper week
Over 30% of the $10 trillion US economy is impacted Over 30% of the $10 trillion US economy is impacted each yeareach year
Commercial aviation loses Commercial aviation loses $1-2 B per year$1-2 B per year due to due to diversions, delays, and cancellations (one diverted diversions, delays, and cancellations (one diverted flight costs $150K)flight costs $150K)
Agriculture losses exceed Agriculture losses exceed $10 B/year$10 B/year
Dutton (2002)Dutton (2002)
Dutton (2002)Dutton (2002)
Actual Losses – Extreme EventsActual Losses – Extreme Events
Pielke and Carbone (2002)Pielke and Carbone (2002)
Cargo shippingCargo shipping– Most expeditious route can save $40,000 per voyage – thousands of ships travel Most expeditious route can save $40,000 per voyage – thousands of ships travel
continuously!continuously!– ExamplesExamples
High temperature and humidity can cause grain to germinate in cargo holdsHigh temperature and humidity can cause grain to germinate in cargo holds Ships affected differently by wavelength of ocean swellsShips affected differently by wavelength of ocean swells
Commercial aviation Commercial aviation – Single diversion averages $10,000 per domestic flightSingle diversion averages $10,000 per domestic flight– Not unusual for one carrier to have 70 diversions at a hub for a single weather event (1-2 Not unusual for one carrier to have 70 diversions at a hub for a single weather event (1-2
hours)hours)– Cost is $700,000 per eventCost is $700,000 per event– Industry loses $1-2 B per year due to weatherIndustry loses $1-2 B per year due to weather
Specific ExamplesSpecific Examples
Source: Weathernews, Inc.Source: Weathernews, Inc.
About About 50%50% of the loss is deemed preventable with of the loss is deemed preventable with better forecasts!better forecasts!
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
Model Model TypesTypesGlobal
(2 weeks)
Model Model TypesTypesGlobal
(2 weeks)
Continental (few days)
Model Model TypesTypesGlobal
(2 weeks)
Continental (few days)
Special
Model Model TypesTypesGlobal
(2 weeks)
Continental (few days)
Special
Operational
Model Model TypesTypesGlobal
(2 weeks)
Continental (few days)
Regional (day)
Local (few hours)
Special
Experimental
Incr
easi
ng
Sk
ill
Trends in Large-Scale Forecast SkillTrends in Large-Scale Forecast Skill
10 km 1 km
Crossing the DivideCrossing the Divide
The next quantum leap in NWP The next quantum leap in NWP
will come when we start will come when we start resolving explicitly the most resolving explicitly the most energetic weather features, energetic weather features, e.g., individual convective e.g., individual convective storms in 3-Dstorms in 3-D
For global models, the For global models, the predictability increases for all predictability increases for all resolvable scales as the resolvable scales as the spatial resolution increases spatial resolution increases – The improvement is The improvement is boundedbounded– Going finer than a few 10s of km Going finer than a few 10s of km
in grid spacing gives little payoffin grid spacing gives little payoff
60 km 30 km
30 km 10 km
Importance of Finer Grid Spacing in Models
Courtesy NCAR
512 km
256 km
128 km
64 km
32 km
16 km
8 km
Each improvement requires 10X computer resources, total increase of 10,000,000!
4 km
Where Are We Today?Where Are We Today? Tremendous advances are being made in the computer-Tremendous advances are being made in the computer-
based prediction of high-impact local weather, such as based prediction of high-impact local weather, such as thunderstormsthunderstorms, owing to, owing to– Increases in computer power and networking capacityIncreases in computer power and networking capacity– Affordability of computersAffordability of computers– Availability of fine-scale observations (NEXRAD Doppler radar)Availability of fine-scale observations (NEXRAD Doppler radar)– Improved understanding of the atmosphereImproved understanding of the atmosphere– Societal need, especially that of weather impacted industries Societal need, especially that of weather impacted industries
(aviation, energy, recreation, defense)(aviation, energy, recreation, defense)
Example : March 28, 2000 Fort Example : March 28, 2000 Fort Worth Tornadic StormsWorth Tornadic Storms
Tornado
NWS 12-hr Computer Forecast Valid at 6 pm NWS 12-hr Computer Forecast Valid at 6 pm CDTCDT
No No Explicit EvidenceExplicit Evidence of Precipitation in North of Precipitation in North TexasTexas
6 pm 7 pm 8 pmR
adar
Hourly Radar Observations(Fort Worth Shown by the Pink Star)
6 pm 7 pm 8 pmR
adar
Com
pu
ter
For
ecas
t
2 hr 3 hr 4 hr
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
UncertaintyUncertainty We never know the complete state of We never know the complete state of
the atmosphere everywhere, with the atmosphere everywhere, with perfect accuracyperfect accuracy
Small observation errors can grow Small observation errors can grow with time in a forecast (chaos)with time in a forecast (chaos)
Rather than run a Rather than run a singlesingle forecast from forecast from one estimate of the current one estimate of the current conditions, we run conditions, we run severalseveral based upon based upon equally plausible initial conditions to equally plausible initial conditions to account for observational uncertaintyaccount for observational uncertainty
This is “ensemble forecasting”This is “ensemble forecasting”
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!!
Forecast #1Forecast #1
Forecast #50Forecast #50
Forecast #2Forecast #2
Forecast #3Forecast #3
Recent Real Time Experimental Forecasts Recent Real Time Experimental Forecasts Run by OU for the National Weather Run by OU for the National Weather
ServiceService
Actual Radar Observations
Recent Real Time Experimental Forecasts Recent Real Time Experimental Forecasts Run by OU for the National Weather Run by OU for the National Weather
ServiceService
24 Hour Forecast Actual Radar Observations
A Foundational QuestionA Foundational Question
Can computer forecastCan computer forecasttechnology. . .technology. . .
. . . explicitly predict this. . . explicitly predict thistype of weather?type of weather?
The Answer Appears to be “Yes,” But NewMethodologies May Be Needed…
Predicting Storms and Anticipating Predicting Storms and Anticipating Tornadoes Requires Fine-Scale Tornadoes Requires Fine-Scale
ObservationsObservations
NEXRAD Doppler Radar Network
Current Operational Radar System in Current Operational Radar System in USUS
NEXRAD Doppler Radar Network
#2. Earth’s curvature prevents 72% of #2. Earth’s curvature prevents 72% of the atmosphere below 1 km from being the atmosphere below 1 km from being
observedobserved
#1. Operates largely independent#1. Operates largely independentof the prevailing weather conditionsof the prevailing weather conditions
#3. Operates entirely independent from#3. Operates entirely independent fromthe models and algorithms that use its the models and algorithms that use its
datadata
The Limitations of NEXRADThe Limitations of NEXRAD
Source: NWS Office of Science and Technology
NEX
RA
DN
EX
RA
D
The ConsequenceThe Consequence
New NSF Engineering New NSF Engineering Research Center for Research Center for
Adaptive Sensing of the Adaptive Sensing of the Atmosphere (CASA)Atmosphere (CASA)
UMass/Amherst, OU, CSU, UPRMUMass/Amherst, OU, CSU, UPRM Concept: inexpensive, phased array Doppler radars on Concept: inexpensive, phased array Doppler radars on
cell towers and buildingscell towers and buildings Dynamically adaptive dynamicDynamically adaptive dynamic sensing of multiple sensing of multiple
targets while simultaneously meeting multiple end-user targets while simultaneously meeting multiple end-user needsneeds
Oklahoma Test Bed: Spring 2006Oklahoma Test Bed: Spring 2006
The $1M Question: Will Numerical Models Ever Be The $1M Question: Will Numerical Models Ever Be Able to Able to PredictPredict Tornadoes? Tornadoes?
Schematic Diagram of a Supercell Storm (C. Doswell)
The FutureThe Future The National Weather Service will begin running models The National Weather Service will begin running models
to to explicitly predictexplicitly predict thunderstorms thunderstorms Private companies will Private companies will
play a major role in play a major role in providing customized providing customized numerical forecasts for numerical forecasts for weather-sensitive weather-sensitive industries, especially industries, especially energy and aviationenergy and aviation
The FutureThe Future Human forecasters will continue to Human forecasters will continue to
be essential, though with changing be essential, though with changing rolesroles
Contact InformationContact Information
Kelvin K. DroegemeierUniversity of Oklahoma
Sarkeys Energy Center, Suite 1110100 East Boyd StreetNorman, OK 73019Email: [email protected]: 405-325-0453Fax: 405-325-7614Mobile: 405-413-7847