the challenges of weather prediction for agriculture: from weather rocks to supercomputers national...
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The Challenges of Weather Prediction for Agriculture:
From Weather Rocks to Supercomputers
National Farm Business Management ConferenceFargo, North Dakota
June 14, 2010
Leon F. Osborne, Jr.Chester Fritz Distinguished Professor of Atmosphere SciencesChester Fritz Distinguished Professor of Atmosphere Sciences
University of North DakotaUniversity of North Dakota
PresidentPresident
Meridian Environmental Technology, Inc. Meridian Environmental Technology, Inc.
Grand Forks, North DakotaGrand Forks, North Dakota
Perceptions & Attitudes Towards Weather & Weather Forecasting
• “Weather: Everyone talks about the weather but no one ever does anything about it!”
• “Weather Forecasting: . . . – where you can always be wrong and still have
a job!!”
AgWeather
Challenges
The Weather Challenge:
Providing reliable, timely and accurate weather and climate information to support agricultural decision-making that meets producer expectations
Defining Realistic Expectations
• Mitigation of weather impacts on crop productivity drives the need for reliable weather information
• Expectations are that information will be clearly stated, easily understood, and accurate
Ag Producer Challenge
• Knowing what constitutes a realistic expectation of accuracy in spatial and temporal extents
• How?– Understanding factors associated
with defining weather and climate conditions
– Awareness of forecasting limitations
– Seeking out proven and trusted sources of information
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What is ‘Risk Management’
• Definition: “Protection of life, property, and economic assets through threat minimization”
• Relationship to weather: The understanding of future conditions dictated by variations in global weather patterns
• Dominant Weather Sources Available: – Federal government & university services– Private-sector Tailored Weather Services
Major Weather & Climate Factors
• Extraterrestrial forcing
• Land surface variations
• Ocean storage and transport
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Weather & Climate is the Interaction of the Earth and Its Atmosphere to Sunshine
Latitude
Elevation
Water resources
Ocean currents
Topography
Vegetation
Prevailing wind currents
Weather & Climate Starts with the Sun
• The Earth’s surface, clouds, and the moisture in the atmosphere permits the solar radiation to warm the atmosphere
from IPPC2001
The surface temperature of the
Earth has increased, particularly over the
past 100 years.
Sept. 2001Nov. 10, 2009
Solar Cycles and Sunspots
• Occur in 11-year cycles• 2009-10 sunspot minimum
– Most dramatic in 50 years
• Promoted cooler 2009 summer conditions
5 Jan 201010 Feb 2010
Sunspots Minima Over Past Century
2009
Is this a noticeable impact on our annual weather?
Sunspots and Solar Irradiance
• Lower number of sunspots over time represents less solar output and less warming of the Earth
El Nino Southern Oscillation (ENSO)
• Sea surface temperature variation – Leads to alteration in atmospheric
circulations
• Alters from warm to cold– Cycle of 2 to 7 years– El Nino (warm) & La Nina (cold)
• Impacts vary– Primary direct precipitation and
temperature impact on Northern Plains in winter
– Indirect (and most significant) impact is influence on jet stream flow (storm track)
El Nino
La Nina
Short-Term Climate & Weather: All About the Jet Stream Pattern
Split Jet Stream Pattern
Global Circulation Centers
• Semi-Permanent features that respond to long-term solar and terrestrial forcing– Annual positioning determines
seasonal weather conditions
• Example - Bermuda High– Dictates moisture flow in
summer east of Rockies– Responds to ocean
temperatures & temperature variations between pole and equator
‘Storm Track’ is related to the Orientation of the Jet Streams
• Position and orientation controls short-term to seasonal . . .– Temperature– Precipitation
‘Warm’ & Dry
Cool & Wet
LLCold & Wet
Global Weather / Climate Patterns
Dictate Soil Moisture Availability
• Distribution of wet and dry conditions depend upon global weather conditions and/or long-term climatic conditions
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DailyWeather Conditions• Surface
conditions depend upon upper-level wind currents
• Jet stream orientation defines weather patterns
LL
Making of a Weather Forecasts
• Data from the . . .– Atmosphere– Ocean– Land
• Proper combination of data
• Use of computer models
• Generation of user information
Weather Data
Weather Satellite
Constitutes ~ 96% of data used for weather computer models
Weather Radar
• Detects precipitation-size particles in clouds
• Amount of radar transmitted microwave radiation reflected back provides indication of particle size and concentration
WeatherRadar
DetectedWeather Radar Beam
UndetectedWeather
4-18
Weather Radar
• Readily available to the public as images– Often misinterpreted by the untrained user!!
• Raw data used within weather models
Combination of Heterogeneous Data Fields
Satellite Data
Weather Radar Data
Atmospheric Winds
Surface Conditions
Atmospheric ThermalStructure
Result of Parameter Integration is Joined with a Geospatial Domain to Produce Information for Distribution
= Three-Dimensional Data Assimilation
Mapping of Solution onto Geographic Framework
Forecasts every mile
Improved Weather Prediction Models
C RQ
ZXA
TT TTffU
VS
W
• Models the atmosphere and land surface in terms of mathematical physics
• Utilizes high-speed computing to generate 100s of ‘possible realities’ that can be statistically combined to produce a better ‘estimate’ as to which prediction is correct
Weather Information at Specific LocationsWeather Information at Specific Locations
Weather Information Content
• Precipitation (Type, Rate, Amount)
• Wind Speed & Direction
• Temperature
• Sunshine Amount / Cloud Cover
• Multi-Depth Soil Temperature
• Multi-Depth Soil Moisture Content
• Leaf Wetness
Data … Data … Achilles Heel of Weather Forecasting
• Only 60 years of 3-D global weather analyses1948-2007
• ~50 years of global sea-surface temperatures
• Limited accurate global atmospheric observationsU.S. - 1221 stations with data since 1900> 75% of globe has less than 75 years of continuous
weather observations
• Even today only limited observations are collected from 10-meters to 1,000 meters above the EarthThe most crucial region to understanding the relationship
between the Earth and atmosphereDiminishes ability to provide accurate agricultural weather
forecasts!!
Accuracy versus Predictability
• The closer in time of an event the more likely accuracy will be higher
• The use of longer timeframe prediction is subject to the amount of “risk” one is willing to accept
Use of Weather Predictions• Weather predictions are unregulated and can
be provided by trained and un-trained individuals– Important to understand the difference between a
weathercaster and a meteorologist (or atmospheric scientist)
• No weather prediction system is perfect and likely never will be
• The accuracy and skill of the prediction will always diminish the further into the future the prediction
Varieties of Weather Predictions And Their Risk (Accuracy) • Short-Range Weather Forecasts (0 - 10 Days)
– Highest level of accuracy (lowest risk) … Typical Accuracy > 85%– Deterministic forecasts based upon physical models of the atmosphere
• 30-Day Forecast Maps– Accuracy varies by season and locale with greatest accuracy along
coastal regions … Typical Accuracy > 75% – Combination of deterministic and statistical models of the atmosphere
• Climate (Seasonal) Outlooks– Compilations of recent historical data, climate statistics and forecast
verifications … Typical Accuracy > 60%– Statistical models comparing past patterns with global weather
circulation projections
Expected 2010 Weather
• El Nino conditions of 2009-10 winter shifting to La Nina conditions for second half of 2010– Cooler conditions across Great Basin through
Northern Plains– Wet conditions from Intermountain West through
the Central Plains and Midwest– Hot conditions from Kansas to North Carolina– Dry conditions along Gulf Coast States
Drought Outlook
Early to Mid Summer 2010
Above NormalAbove NormalTemperaturesTemperatures
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2010 Weather Expectations
Below NormalBelow NormalPrecipitationPrecipitation
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Mid-Summer to Mid-Fall 2010
Near NormalNear NormalPrecipitationPrecipitation
Below NormalBelow NormalPrecipitationPrecipitation Above NormalAbove Normal
TemperaturesTemperatures
Near NormalNear NormalTemperaturesTemperatures
Below NormalBelow NormalPrecipitationPrecipitation
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2010 Weather Expectations
Above NormalAbove NormalTemperaturesTemperatures
