Transcript Road Weather Management Workshop

The Challenges of Weather Prediction
for Agriculture:
From Weather Rocks to Supercomputers
Leon F. Osborne, Jr.
Chester Fritz Distinguished Professor of Atmosphere Sciences
University of North Dakota
President
Meridian Environmental Technology, Inc.
Grand Forks, North Dakota
National Farm Business Management Conference
Fargo, North Dakota
June 14, 2010
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!!”
Ag
Weather
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
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• Land surface variations
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• Ocean storage and transport
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Weather & Climate is the Interaction of the
Earth and Its Atmosphere to Sunshine
Latitude
Topography
Elevation
Vegetation
Water resources
Prevailing
wind
currents
Ocean 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
The surface
temperature of the
Earth has increased,
particularly over the
past 100 years.
from
IPPC2001
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
2010
Sept.
2001
1010,
Feb
2010
Nov.
2009
2009
Sunspots Minima Over Past Century
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
El Nino
– 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)
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
L
Global Weather / Climate Patterns
Dictate Soil Moisture Availability
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• Distribution of wet and dry conditions depend
upon global weather conditions and/or longterm climatic conditions
Daily
Weather
Conditions
• Surface
conditions
depend upon
upper-level wind
currents
• Jet stream
orientation
defines weather
patterns
L
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
Detected
Weather
Radar Beam
Undetected
Weather
Weather
Radar
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
Mapping of Solution onto
Geographic Framework
Weather Radar Data
Atmospheric Winds
Atmospheric Thermal
Structure
Surface
Conditions
= Three-Dimensional Data Assimilation
Forecasts every mile
Result of Parameter
Integration is Joined with a
Geospatial Domain to Produce
Information for Distribution
Improved Weather Prediction Models
• 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
T
ZV
S
X
AW
CUR
Q
Tf
Weather 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 …
Achilles Heel of Weather Forecasting
• Only 60 years of 3-D global weather analyses
1948-2007
• ~50 years of global sea-surface temperatures
• Limited accurate global atmospheric observations
U.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 Earth
The most crucial region to understanding the relationship
between the Earth and atmosphere
Diminishes 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
2010 Weather Expectations
Above Normal
Precipitation
Above Normal
Temperatures
Below Normal
Temperatures
Above Normal
Precipitation
Above Normal
Temperatures
Below Normal
Precipitation
Early to Mid Summer 2010
Near Normal
Precipitation
2010 Weather Expectations
Near Normal
Precipitation
Below Normal
Precipitation
Near Normal
Temperatures
Below Normal
Precipitation
Below Normal
Precipitation
Above Normal
Temperatures
Mid-Summer to Mid-Fall 2010
Above Normal
Temperatures
Thank You!
Contact Information:
[email protected]
www.meridian-enviro.com
701-792-1800