Post on 27-Apr-2018
Weather Observers
Duane Friend
University of Illinois Extension
Weather Observers Duane Friend
University of Illinois Extension
What Will be Covered
• Why we have seasons
• The Composition of the Atmosphere (Why is the sky blue?)
• Heat and Temperature (What does a “Feels Like” temperature mean?)
What Will be Covered
• Air Pressure and Winds (Why does most of our storms come from the west?)
• Clouds and Precipitation (What do different clouds mean for future weather?)
• Climate and Weather (How do scientists predict future climate, and how accurate are they?)
What Will be Covered
• Volunteer Precipitation Monitoring- Training in the Community Collaborative Rain, Hail, and Snow (CoCoRaHS) monitoring program
The Earth and Seasons
• The Earth tilts on its axis
• As the Earth moves around the sun,
this changes the angle that the sun
hits the Earth’s surface
• This changes the amount of energy
the Earth’s surface receives at different latitudes
http://www.physicalgeography.net/fundamentals/7f.html
Courtesy NASA/NOAA
23.50 N 23.5 0 S
http://www.physicalgeography.net/fundamentals/7f.html
http://www.physicalgeography.net/fundamentals/7f.html
Noon Sun angle at 40 degrees North Latitude
73.50
500
26.50
Sun
Sun
June Solstice
Equinoxes
December Solstice
During the year, the earth gets closer or farther from the sun, but this does not have a great effect on seasonality
In fact, the earth is closest to the sun
at a time you may not expect-
http://www.physicalgeography.net/fundamentals/7f.html
Daylight Hours Have a Small Affect on Seasonality
• Through winter and spring, Jacksonville, IL gains about 2 to 3 minutes of daylight per day, with the longest daylight experienced on the first day of summer (approximately 15 hours)
• Through summer and fall, we lose 2-3 minutes of daylight per day, with the shortest daylight experienced on the first day of winter (9 hours 21 minutes)
Fairbanks, Alaska
• Fairbanks, Alaska, gains 6-7 minutes of daylight per day during winter and spring, with a daylight length of 21 hours 50 minutes on the first day of
summer
• They lose 6-7 minutes of daylight during summer and fall, and have only 3 hours 41 minutes of daylight on the first day of winter
Daylight Length Dependent on Latitude
• At Equator, daylight is always 12 hours
• Daylight hours change more rapidly the farther you move from the Equator.
• At the poles, the sun is up for 6 months or below the horizon for 6 months
Earth’s Atmosphere • Made up of mostly nitrogen and oxygen
• Half of atmosphere is within first 4 miles
• Has particulates (small solids and liquids, which are needed
in small amounts)
• Small amounts of trace gases that include greenhouse gases, such as carbon dioxide and methane
• In general, temperature decreases with elevation in lower levels (on average, about 3 ½ degrees Fahrenheit per 1000 feet)
http://www.physicalgeography.net/fundamentals/7f.html
Temperature decreases
Temperature increases
Temperature decreases
Where “Weather” occurs
Ozone here- Most UV Stopped
Gamma and X Rays Stopped here
Half of Atmosphere Below this point
Sunlight (Solar Energy)
Sunlight Travels as a Wave
• There is an infinite range of wavelengths of sunlight (solar energy).
• The human eye only can detect a small range of this energy- the visible spectrum.
(millionths of a meter)
Majority of Sunlight Reaching Earth’s Surface is in the Visible Spectrum
Incoming Outgoing
Courtesy NASA
What makes the Sky Blue?
• Shorter wavelengths of visible light (violets/blues) gets scattered by air molecules, sending the color off in all directions.
http://www.physicalgeography.net/fundamentals/7f.html
What Happens to All That Energy from the Sun?
Incoming Solar Radiation
http://www.physicalgeography.net/fundamentals/7f.html
What comes in eventually goes out
http://www.physicalgeography.net/fundamentals/7i.html
30 + 6 + 64 = 100%
The Earth’s Atmosphere is Mostly Heated from the Earth’s Surface
Condensation = Heat released to atmosphere
• The heat released by condensation is the single most important way heat is transferred from earth’s surface to the atmosphere.
• The release of heat from condensation can occur hundreds or thousands of miles from where the heat was picked up by evaporation
Greenhouse Effect
• The Greenhouse Effect is a natural process (we will talk about the Enhanced Greenhouse Effect and Global Warming later)
• Earth’s current average temperature is 59 degrees F. Without the effect, it would be 5 degrees F.
• It occurs when greenhouse gases absorb energy trying to escape to space, and redirects most of it back to Earth.
Greenhouse Gases
• Gases like carbon dioxide, methane, and nitrous oxides have the ability to absorb heat that is trying to escape into space.
• The heat is released by the gases, but a lot of it is sent back towards earth instead of heading out to space.
When the heat is released, it goes out in all directions
A Lot Heads Back to Earth
What Happens if Greenhouse Gases Increase?
• Increases of Greenhouse gases have increased the Greenhouse effect, leading to warming of the lower atmosphere.
• Cause and Effect- we’ll talk about this more when we discuss Climate Change……
Things that cause temperature differences around the world
• Sun angle
• Elevation
• Daylight length
• Differences in heating from land and water
Land and Water Heating Differences
• Land heats up faster and to a greater extent than water does
• Land cools faster and to a greater extent than water does
• Water acts as a moderator of temperature.
Heat Index and Wind Chill
• The Heat Index, sometimes referred to as the apparent temperature is given in degrees Fahrenheit. The Heat Index is a measure of how hot it really feels when relative humidity is factored in with the actual air temperature.
• The NWS Windchill Temperature (WCT) index uses advances in science, technology, and computer modeling to provide an accurate, understandable, and useful formula for calculating the dangers from winter winds and freezing temperatures. The index:
• Calculates wind speed at an average height of five feet, the typical height of an adult human face
• Incorporates heat transfer theory, heat loss from the body to its surroundings, during cold and breezy/windy days
• Assumes no impact from the sun (i.e., clear night sky).
Predicting Daily Temperatures
• Numerical models are used that input current atmospheric conditions, satellite readings, etc.
• These models have been much more accurate in the last 5-10 years, and should continue to improve as computing speed increases. (More speed means more variables can be used in the model)
Air Pressure
• This is the force created by many, many air molecules
• It is not just a downward force
Air Pressure
• Air pressure at sea level is almost 15 pounds per square inch
• Air pressure decreases rapidly
with height
• Air pressure varies due to
temperature and dynamic forces
in atmosphere http://www.physicalgeography.net/fundamentals/7d.html
Aneroid Barometer
NOAA
Air Pressure and Weather
• In general, lower air pressure is related to cloudiness, or unsettled weather
• In general, higher air pressure is related to fair weather
Air Pressure variations
• Thermal- warm surface temperatures = lower pressure
• Cold surface temperatures = higher pressures
http://www.physicalgeography.net/fundamentals/7n.html
Air pressure and wind
• Winds blow from high to low
• Earths rotation changes this at the surface
• Wind is always described in terms of the direction it’s coming from
http://www.physicalgeography.net/fundamentals/7n.html
http://www.physicalgeography.net/fundamentals/7f.html
Idealized pressure and winds
http://www.physicalgeography.net/fundamentals/7f.html
What Really Happens
Stormy
Fair/Desert
Fair/Desert
Stormy
Stormy
Fair
Fair
EQUATOR
300
300
600
600
The Highs and Lows on Weather Maps are Individual Cells
• Dynamic- Rising air = lower pressure
Sinking air = higher pressure
From U. of I. Master Naturalist- Weather and Climate Chapter
The greater the pressure change, the stronger the wind
• Close isobars of air pressure means there’s a strong wind in that area.
http://www.physicalgeography.net/fundamentals/7n.html
El Nino/La Nina
• Normally, there is high pressure off the coast of South America. Winds and warm surface ocean water flows from S. America towards Australia. Deep, cold water comes up to the surface along S. America to replace the surface water that is moving away.
• During an El Nino, warm water starts flowing back towards S. America. Winds also reverse, as S. America coast becomes an area of High pressure.
“Normal”
South America Australia
Cold Water
Warm Water
El Nino Winds/Currents Reverse
Warm Water Heads Towards South America
South America
Australia
La Nina
• La Nina is similar to “normal” conditions in the Pacific, but exhibits unusually cold ocean surface temperatures near S. America
El Nino/La Nina Weather Effects
Courtesy National Weather Service
Humidity and Precipitation
Humidity
• Usually described as Relative Humidity
• This shows how much moisture is actually in the air, compared to the maximum amount the air can hold at that temperature.
Higher Temperatures Can Hold More Water Vapor
Temperature
Water Vapor
This doesn’t mean the air IS holding a lot……
Hair Hygrometer
Source: USA TODAY research by Chad Palmer
Another Method of Describing Humidity is Looking at the Dew Point
Temperature
• At 100% Relative Humidity, the air is holding as much water vapor that it can hold at that temperature. Any excess water vapor will condense back to liquid water.
• As air cools at night, its water vapor capacity decreases. If it cools enough, it reaches its dew point temperature and produces……dew!
High Dew Points Mean Uncomfortable Conditions and Potential for Unsettled
Weather
• Watch out for dewpoints in the 50’s or 60’s in March- may mean potential for storms.
• Dew points in the 70’s during the summer could also mean potential for storms.
Clouds
• 3 main forms- Cumulus, Stratus and Cirrus
• Alto prefix- mid-level cloud
• Nimbo or Nimbus- Precipitation
Cloud formation
• Water vapor has to condense onto small water attracting particles like dust, smoke or pollen
• These tiny droplets collide to make larger droplets
Cloud Pictures
• The following photos are courtesy The Cloud Appreciation Society
http://cloudappreciationsociety.org/
Cloud Pictures
• The following photos came from the Plymouth State University Meteorology Program
Precipitation
Types of Precipitation in Illinois
• Rain
• Snow
• Sleet
• Freezing Rain
• Hail
Rain
• Most rain away from equatorial regions begins as snow, and melts on the way down.
Drop Sizes and Fall Rates
• Cloud droplet = .0008 inches
– Fall rate = .03 ft/sec.
• Rain drop = .08 inches
– Fall rate 21.4 ft/sec.
Snow
Courtesy National Weather Service
Sleet
Courtesy National Weather Service
Freezing Rain
Courtesy National Weather Service
Hail
• Starts as small ice pellets, and increases in size as layers of water freeze.
Courtesy NOAA
Size of Hail Affects Speed
• BB sized hail may fall at less than 24 MPH
• Golf ball sized hail fails around 103 MPH
• Soft ball sized hail falls around 166 MPH! From: NOAA
Reading A Weather Map
http://www.physicalgeography.net/fundamentals/7r.html
Idealized Mid Latitude Cyclone/Low Pressure System
http://www.physicalgeography.net/fundamentals/7s.html
Weather Associated with Fronts
• Prior to warm front passage (Location B): Cool temperatures, wind from southeast or south, pressure decreasing, increasing cloudiness with potential for extended period of precipitation
B
http://www.physicalgeography.net/fundamentals/7s.html
Weather Associated with Fronts
• After warm front passage (Location X): Warmer temperatures, wind shift to southwest, pressure remains steady, skies clear
X
http://www.physicalgeography.net/fundamentals/7s.html
Weather Associated with Fronts
• While Cold front is passing: drop in air pressure, brief intense precipitation
Weather Associated with Fronts
• After passage (Location A): Cool/cold temperatures, pressure increases, skies clear, winds from north or northwest
A http://www.physicalgeography.net/fundamentals/7s.html
If Low Pressure is North of Your Location
• Winds will shift from SE to SW to NW
http://www.physicalgeography.net/fundamentals/7s.html
If Low Pressure is South of Your Location
• Wind shift SE-E-NW
• Expect a period of steady rain/drizzle and a cold easterly wind
http://www.physicalgeography.net/fundamentals/7s.html
Other “Fronts”
• Stationary front
• A front between warm and cold air masses that is moving very slowly or not at all.
Courtesy National Weather Service
Other “Fronts”
• Occluded front
• Formed as a cold front overtakes a warm or quasi-stationary front.
Courtesy National Weather Service
Other Symbols on Weather Maps
• A “trough”
• An elongated area of relatively low atmospheric pressure
Courtesy National Weather Service
Other Symbols
• Dry line
• A boundary separating moist and dry air masses. Usually located between a warm front and cold front.
Courtesy National Weather Service
High Pressure Cells
• High pressure cells do NOT have fronts
• These will generally be associated with clear skies/fair weather
Violent Weather
• Thunderstorms
• Lightning
• Tornadoes
• Derechos
Thunderstorms
4 categories of thunderstorms
• Single cell
• Multi cell
• Multi cell (squall line)
• Supercell
Single Cell
• Forms from convective activity
• May contain brief intense rain, lightning, small hail
• Brief- only 20-30 minutes in length
Multicell line- Training Thunderstorm
• As one cell builds, downdraft creates additional updraft, creating another adjoining cell-
• May be several cells lined up one behind the other (Training effect)
• Creates potential heavy rain, small hail, lighting, weak tornadoes
Training Thunderstorm. Courtesy National Weather Service
Updrafts and Downdrafts
• A thunderstorm's updraft can carry 8000 tons of water aloft per minute
• Rising air in smaller thunderstorms moves at speeds near 40 mph
• When rain begins to fall, they drag the air down around them and a downdraft forms. The rain also is falling into unsaturated air and so some evaporation occurs, cooling the air nearby. This rain-cooled air is now cooler than its surrounding environment and it sinks, helping to form and intensify the downdraft
National Weather Service
Multi cell line (Squall Line)
• Multiple cells, moving side by side
• May have a “gust front” preceed it
• Potential for intense rain, hail, lightning, weak tornadoes
Squall Line. Courtesy National Weather Service
Supercell
• Contains 5-15 mile wide rotating column of air
• Also called “mesocyclone”
• Potential for heavy rain, large hail, lots of lightning, and strong tornadoes
• May last for hours
• Can develop along a dryline
Supercell. Courtesy National Weather Service
Dryline/Supercell development
• Dryline develops in warm sector, between cold and warm front
• Hot, dry air overrides warm, moist air, creating a cap
Hot, dry Air mass
Warm, moist air mass
The hot dry air acts as a cap, preventing the warm moist air from rising for a while……
Once Cap is Punched Through
• Air is extremely unstable- will ascend at upwards of 150 miles per hour
• Rotation develops due to wind shear
Do Storms split apart after crossing a river?
• From the National Weather Service-Unfortunately, there is no proof that storms split or dissipate after they cross rivers...they can, and do, but not in a way that would indicate a pattern. There is no documented evidence that the effects of a river or lake, even a mile wide, has a significant effect on the dynamics of a thunderstorm. The scale of the river is very small when compared with the scale of a thunderstorm that extends five miles or more into the atmosphere and can range from tens of miles to hundreds of miles in diameter
Having Said That, There are Splitting Thunderstorms-
• A thunderstorm which splits into two storms which follow diverging paths (a left mover and a right mover). The left mover typically moves faster than the original storm, the right mover, slower. Of the two, the left mover is most likely to weaken and dissipate (but on rare occasions can become a very severe anticyclonic-rotating storm), while the right mover is the one most likely to reach supercell status (National Weather Service)
Derechos
Photo Courtesy National Weather Service And Brittney Misialek
Derecho Classification
• A straight line wind of at least 58 miles per hour or greater than creates a damage path of at least 240 miles
• The swaths of stronger winds within the general path of a derecho are produced by what are called downbursts
• Occur in irregularly-arranged clusters
Courtesy National Weather Service
The campus of Southern Illinois University suffered extensive damage, with nearly 100 windows blown out of residence halls. An unofficial gust to 106 mph was recorded on the roof of the Carbondale airport. This derecho travelled over 1000 miles in 24 hours.
May 2009 Derecho
Courtesy National Weather Service
Courtesy National Weather Service
Lightning
Formation of charge
• Cloud droplets form from condensation and collision
• Droplets are supercooled-start to freeze around -100 C
• In updraft, ice collides with water that freezes- creates graupel
Charge formation
• As graupel collides with other ice and water, charge is transferred between particles
• Graupel becomes negatively charged (especially if temperatures are -10 C or colder)
Charge formation
• Negative charges build up near base of cloud
• Positive charge induced from ground
• Electric field between cloud and ground up to 10’s of thousand’s of volts
• Ionized path created between cloud and ground must first be created- called a stepped leader- starts from cloud and follows path of least resistance
• As stepped leader gets to within 150 feet of ground, it meets a leader coming up from the ground, to complete path
• Negative discharge occurs
• Discharge may be repeated up to 4 times
• Each lasts about 30 microseconds
• Peak power around 1012 watts
• Positive charges can be pushed into upper parts of cloud, especially anvil
• Can create Positive cloud/ground strikes
• More powerful, longer duration, than negative strikes
Courtesy National Weather Service
Other lightning types?
• Sheet lightning- lightning bolt obscured by clouds
(not a sheet of electricity)
• “Heat” lighting- lightning bolt below horizon
(not formed from heat)
Ball Lightning
• Very rare
• Little known about how/why it occurs
Lightning
• Air from strike heated to over 40,000 degrees F
• Creates shock wave which disintegrates into…………
THUNDER
Thunder
• Sound “rolls or rumbles” due to:
– Length of lightning bolt- sound travels 1/5 mile per second- sound from part of bolt closest to you will reach your ears before the farthest part of the bolt
– Echoing off of clouds and other obstacles
Different Thunder Sounds
• http://www.ec.gc.ca/foudre-lightning/default.asp?lang=En&n=4EFD3A52-1
Lightning Safety
• Twenty-three Americans died from lightning in 2013, the fewest since records began in 1940.
From: USA Today
Before Lightning Strikes...
If you can hear thunder, you are close enough to the storm to be struck by lightning. Go to safe shelter immediately! When a Storm Approaches... Find shelter in a building or car. Keep car windows closed and avoid convertibles. Telephone lines and metal pipes can conduct electricity. Unplug appliances and turn off the air conditioner. Avoid using the telephone or any electrical appliances. Avoid taking a bath or shower, or running water for any other purpose.
If Caught Outside... If you are in the woods, take shelter under the shorter trees. If you are boating or swimming, get to land and find shelter immediately! If you can’t make it to land, crouch down in the boat, away from metal if possible. Protect Yourself Outside... Go to a low-lying, open place away from trees, poles, or metal objects. Make sure the place you pick is not subject to flooding.
Be a Very Small Target! Squat low to the ground. Place your hands on your knees with your head between them. Make yourself the smallest target possible. Do not lie flat on the ground -- this will make you a larger target!
After the Storm Passes... Stay away from storm-damaged areas. Listen to the radio for information and instructions. If Someone is Struck by Lightning... People struck by lightning carry no electrical charge and can be handled safely. Call for help. Get someone to dial 9-1-1 or your local Emergency Medical Services (EMS) number. The injured person has received an electrical shock and may be burned, both where they were struck and where the electricity left their body. Check for burns in both places. Give first aid if trained to do so.
Tornadoes
• Need warm, moisture laden air at low levels
• Wind shear aloft- winds moving at different directions and speeds
• Much the same conditions needed as for a supercell- why they are often associated with them
Tornado Computer Simulation
• http://access.ncsa.illinois.edu/Stories/supertwister/tornado/tubecone_popup.htm
• Developed by the University of Illinois National Center for Supercomputing Applications and Lou Wicker at the National Severe Storms Lab
• In this visualization, orange spheres are rising; blue spheres are falling. Swaying cones are used to symbolize the speed and direction of the wind at ground level
Tornado statistics
• Maximum Doppler estimated wind speed- over 300 mph
• Can range in size from a few feet to almost a mile wide
• Majority of tornadoes are weak (EF 1)
FUJITA SCALE DERIVED EF SCALE OPERATIONAL EF SCALE
F Number Fastest 1/4-mile
(mph) 3 Second Gust
(mph)
EF Number
3 Second Gust
(mph)
EF Number 3 Second Gust
(mph)
0 40-72 45-78 0 65-85 0 65-85
1 73-112 79-117 1 86-109 1 86-110
2 113-157 118-161 2 110-137 2 111-135
3 158-207 162-209 3 138-167 3 136-165
4 208-260 210-261 4 168-199 4 166-200
5 261-318 262-317 5 200-234 5 Over 200
Tornado safety
• Go to a small sturdy room on a lower level.
• If in a mobile home/RV, get to something safer
• If in a car, leave seat belt on and get your head as low as possible, and cover your head- don’t go to an overpass
• If no car or building available, lie flat in a depressional area, covering your head
Predicting Weather
• Can use things like clouds, wind direction, pressure to make short term predictions
Photo courtesy NOAA
Using Clouds to Predict Weather
• Cumulus clouds with no growth = fair weather
• Cirrostratus creating rainbow around sun = approaching precipitation
• Altocumulus (mackerel sky) = approaching warm front
• Cirrus = fair weather
Using Air Pressure to Predict Weather
• Rapidly falling air pressure- Expect stormy conditions within 24 hours
• Slowly falling air pressure- Expect increase
in cloudiness, potential for precipitation
• Rapidly rising air pressure- Expect period
of cold temperatures and fair skies
NOAA
Using Winds to Predict Weather
• Strong SE winds- Good chance of warmer weather within next 36 hours
• Strong SE to E winds- Expect extended period of cold temperatures and clouds/precipitation
• Strong NW wind- Expect 1-2 days of cold and dry weather
• Strong SW wind- Expect clouds/precipitation followed by colder temperatures
Climate Change
• The following information is from Dr. Don Wuebbles, Atmospheric Scientist at the University of Illinois. Dr. Wuebbles is an expert in numerical modeling of atmospheric physics and chemistry. He shares in the 2007 Nobel Peace Prize for his work with the international Intergovernmental Panel on Climate Change.
Observed and Projected changes in Climate in the
Midwest
Don Wuebbles Department of Atmospheric Sciences
University of Illinois
July 2013
The Science is Clear: Climate change is one of the most important issues facing humanity
The scientific evidence shows that our climate is changing, and that human activities are identified as the primary cause.
All major science organizations have put out strong statements about this issue.
e.g., National Academy of Sciences, American Geophysical Union, American Meteorological Society, American Physics Society, American Chemical Society, Ecological Society of America, American Assoc. Adv. Of Science
Observational
Records Clearly
Indicate a
Changing Global
Climate
The Greenhouse Effect: Sustains Life on Earth, but being Affected by Human
Activities
Natural Drivers of Climate
Variations in the Earth's
orbit (Milankovitch
effect)
Stratospheric aerosols from
energetic volcanic eruptions
Variations in the
energy received from the
sun
Human Factors in Climate
Changes in atmospheric gases
Changes in particles from burning fossil fuels and biomass
Strong evidence that the climate change occurring is primarily human induced
Human fingerprints have been identified in many aspects of climate change •Surface and vertical temperature
•Stratospheric and tropospheric
temperature change
•Height of the tropopause
•Precipitation
•Vertical structure of upper-ocean
temperature changes
•Ocean heat content
•Atmospheric moisture
•Arctic sea ice
•Sea-surface temperature changes in
hurricane formation regions
Observed Decrease in Solar Irradiance since 1978
The scientific evidence points to human activities as the
primary cause of the changing climate.
Natural processes cannot account for
observed global climate changes over
last 5 decades
• Increasing temperature
• Increasingly intense downpours
• Rising sea level
• Rapidly retreating glaciers
• Thawing permafrost
• Longer growing season
• Longer ice-free season in the ocean and on lakes and rivers
• Earlier snowmelt
• Changes in river flows
Since the 2009 U.S. Assessment: Science Shows Climate Changes Continue in U.S.
Surface Temperature Analysis • Based on NWS Cooperative Observer Network
• Potential sources of bias
– Change to electronic instrumentation in 1980s:
lowering of Tmax, raising of Tmin
– Change in typical observing time from late afternoon
to early morning: lowering of both Tmax and Tmin
– Station siting
• NCDC uses objective detection schemes to
identify shifts and estimate corrections
• New climate division data set, based on the
adjusted station data
U.S. average temperature has risen by 1.5oF since 1895; mostly since 1980
Data from NOAA NCDC
Increase occurring in all seasons
Contiguous U.S. Temperature Trends
Midwest: Increasing Trend in Temperature
Winter Spring
Summer Fall
U.S. Growing Season is Lengthening
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190
1895 1910 1925 1940 1955 1970 1985 2000
Le
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th o
f G
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Se
aso
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(da
ys)
Year
Observed Trends: 1991-2011 relative to 1901-1960
Midwest
Changes in Frost-Free Season relative to 1901-1960
Data from NOAA NCDC
Increasing trend: U.S. breaking many more heat records than cold records
Based on Meehl et al., Science (2009)
1800 U.S. weather stations from 1950
2011 3 to 1 2012: 10 to 1
Last 3-5 Decades: U.S. Increasing trend in Heat Waves, less Cold Waves
Midwest: no trend in Heat Waves, but less Cold Waves
171
Observed Increasing Trend in U.S. Precipitation Both in Decadal trends and 1991-2011 relative to 1901-1960
Based on NOAA NCDC data
Midwest: Increasing Trend in Precipitation
Especially Spring and Summer
Observations show major increase in very heavy precipitation events over last 50 years
defined as the heaviest 1 percent of all daily events from 1958 to 2010
Extreme Precipitation in Midwest
174
0.0
0.5
1.0
1.5
2.0
2.5
1895 1910 1925 1940 1955 1970 1985 2000
Extr
em
e P
reci
pit
atio
n In
dex
Year
Blue = 1-yr storms, highest value: 1998 Red = 5-yr storms, highest value: 2004 Green = 20-yr storms, highest value: 2008
Certain types of extreme weather events have become more frequent and intense – Heat Waves, Floods and Droughts in some regions Floods (USGS, 2011) Droughts (PHDI)
Increase: Midwest, Northeast Decrease: Southwest Increase: West, Southeast
Time series of billion dollar disasters in the U.S.
Attribution: There is a Detectable Human Influence on Recent Major Weather Events
Examples
• UK flooding in 2000
• European heat wave of 2003
• The cold U.S. of 2008
• Cold European winter 2009/2010
• Moscow heat wave of 2010
• The 2011 drought in Texas and Oklahoma
Temperature is Expected to Continue to Increase over the U.S.
Relative to 1901-1960
Future Climate Change Depends on Our Decisions about Emissions
Midwest Temperature
Changes 2041-2070
Compared to 1971-2000
High emissions scenario (A2)
Precipitation Projections: Low and High Scenarios
2070-2099 of seasonal average precipitation relative to 1971-2000
Midwest Precipitation
Changes 2041-2070
Compared to 1971-2000)
High emissions scenario (A2)
Top 2%
The Future: Increasing Tendency for Severe Precipitation Events in U.S.
Historical and projected changes in the amount of precipitation falling in the top 1% of events
Historical
High scenario
Low scenario
High scenario
Low scenario
Midwest: Severe Precipitation Events likely to increase (new CMIP5 analyses)
Historical and projected changes in the amount of precipitation falling in the top 1% of events
100%
Historical
High scenario
Low scenario
Illinois Summers Likely to be More
Like Southern U.S. by End of Century Based on summer average temperature and precipitation
Climate Change is likely to affect us in many different ways
0
10
20
30
40
50
60
70
80
1961-1990 2010-2039 2040-2069 2070-2099
Da
ys
pe
r Y
ea
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ve
r 9
0o
F Historical
Low emissions future
High emissions future
0
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1961-1990 2010-2039 2040-2069 2070-2099
Da
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Historical
Low emissions future
High emissions future
Chicago: Extreme Heat & Public Health Projected Increase in Maximum Temperatures
By end-of-century, number of days over 90oF (32oC) Low emissions: More than 2x greater than today High emissions: More than 4x greater than today
By end-of-century, number of days over 100oF (38oC) Low emissions: More than 4x as many as today High emissions: More than 15x as many as today
Heat Waves are Projected to Increase
Chicago 1995-type heat wave will become routine by end of century – as many as 3 per year by 2100
0
5
10
15
20
25
30
35
1960 1980 2000 2020 2040 2060 2080
Nu
mb
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of
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at
Wa
ve
s p
er
Dec
ad
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Lower Emissions
Higher Emissions
Rainfall and Water Resources Heavy Rainfall Events (> 2.5 inches)
2.5” per day: approximate threshold for combined runoff-sewer overflow into Lake Michigan (can lead to beach closings)
Increases of almost 2x under lower emissions and 3x under higher
Agriculture faces increasing challenges from
heat stress, water stress, pests, diseases, and weather extremes
©Copyright
Infrastructure and Economy Less Energy Demand in Winter, but Much Greater Demand in
Summer
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High emissions future
Decreased demand for gas and oil for winter heating
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1961-1990 2010-2039 2040-2069 2070-2099
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Low emissions future
High emissions future
Increased demand for electricity for summer cooling
Summer Winter
We must meet the Challenge
The worst impacts can be avoided
• Avoid the unmanageable
• Manage the unavoidable
Many Pathways to Reducing Emissions
US Army Corps of Engineers
Dave Saville, courtesy of FEMA
The benefits of strong, early action on
climate change outweigh the costs
There are Many Indicators of a Changing Climate
Sea Level Rise
N.H. Snow Cover
Troposphere T Land surface air T
Marine air T
Sea surface T Ocean heat content
Specific humidity
Arctic sea ice extent
Glacier mass balance
Illinois Climate Past, Present, and Future
Slide Credits
• Illinois State Water Survey
• Illinois State Museum
• Dr. Jim Hansen, Columbia University
Climate Tipping Points presentation
Outline
• Illinois’ climate history
• Current Illinois climate
• Future Illinois climate
• Climate affects on vegetation, wildlife, etc
Climate changes
• During that time, what is now Illinois moved from south of the Equator to close to its current position, changing from a tropical climate to dry, cool desert , to boreal forest
Land Areas 65 Million Years Ago
Courtesy Dr. Jim Hansen, Columbia University
Courtesy Dr. Jim Hansen, Columbia University
Pleistocene and Glaciers
• From about 1.8 million years ago to about 10,000 years ago, Illinois has been reshaped by several glacial episodes. Climate during glacial episodes in Illinois would have been cool and wet, while interglacial periods would have been as warm or warmer than present.
Extent of Glaciation in Illinois
Period
interglacial 10,000 B.C.
Wisconsin glacial
interglacial
Illinoian glacial
interglacial
Kansan glacial
interglacial
Nebraskan glacial
Illinois Climate 15,000 years ago Cool Tundra
• Near the ice, Illinois would have had a cool boreal forest, with spruce and other trees prevalent.
• These forests expanded and contracted as ice ages grew and waned.
Courtesy Illinois State Museum
Muskox about to be Eaten
Movement of Prairies
• Boundaries of prairies and forest have changed – prairies extended as far as Ohio and Pennsylvania during a warmer climate several thousand years
ago.
• Forests came into the
southern prairie during
the Little Ice Age,
1300-1850
Illinois Climate Now
Average Annual Precipitation
Average Annual High Temperature
Average Annual Low Temperature
Winter
2010 2010
1895
1895 1895
59
47
60
48
36
20
Spring
Fall
2010 2010
1895
78
69
Summer
1895 1895
1895 1895
2010 2010
2010 2010
5 inches 5 inches
5 inches 2.5inches
17 inches
17 inches
17 inches
10 inches
Spring Summer
Fall Winter
Future Climate in Illinois- What will it be?
• Climates naturally fluctuate
• Human created inputs affect this change
• How to predict what climate will become
Melt descending into a moulin, a vertical shaft carrying water to ice sheet base.
Source: Roger Braithwaite, University of Manchester (UK)
Surface Melt on Greenland
Computer Modeling
Research shows wood ticks, wild turkeys, badger, opossum, and flying squirrels are extending their ranges north. Warming climate may also be contributing to increasing range of gypsy moths and other exotic insect species.
Source: National Park Service
"We’re seeing northern range shifts of lots of birds and butterflies," said Dr. Camille Parmesan, a professor of conservation biology at the University of Texas and a member of the United Nations panel on climate change
Potential Effects of Global Warming in Illinois Farm Ponds
• If average summer temperatures increase, this is increase water temperatures in farm ponds, decreasing dissolved oxygen levels.
• Increased aeration may be needed to avoid fish kills.
Global Dimming
Pollutants in the form of aerosols are believed to be reducing the amount of sunlight reaching earths surface. Estimates of the reduction range from 10 to 30 percent.
This reduction masks the effects of global warming. As more efforts are made to reduce air pollution, global warming may increase at a faster rate.
From Dimming the Sun, NOVA , PBS Online
Can we have another Ice Age?
• Earth-Sun relationship seems to trigger recent glacial episodes
• Based on earth’s axis tilt, distance from sun, and wobble of axis, working on approximately 100,000 year cycles.
Milankovic Cycles
• Change in earths orbit
• Change in earths tilt
• Earth’s wobble on its axis
Earths orbit
• Changes from circular to more elliptical over about 100,000 year cycle
• More elliptical orbit means earth receives less energy during that time
Earth’s Tilt Changes
• Varies from about 22.1 to 24.5 degrees
• When more vertical, polar areas
receive less sunlight
http://www.physicalgeography.net/fundamentals/7y.html
Axis wobble changes the time of year when the N. Hemisphere is pointing towards the
Sun • Currently, N. Hemisphere is tilted towards the sun when the Earth is farthest away (during our summer) = shorter winters for us • Wobble will cause N. Hemisphere to be tilted away from the sun when earth is farthest from the sun (during our winter) in about another 13,000 years, = longer winters for us
http://www.physicalgeography.net/fundamentals/7y.html
Conclusions • Climate is changing in the U.S. largely as a result of
human activities; these changes are likely to continue (depends on us)
• Growing season is getting longer.
• Certain types of extreme weather events are becoming more common. Trends likely to continue. – More precipitation coming as larger events.
– Heat waves are generally increasing, and will likely become longer and more severe.
– Cold waves are becoming less common.
– Increasing risk of floods and droughts in some regions.
• Sea levels are increasing and likely to increase by 1 to 4 feet over this century.
• These changes are significantly affecting the U.S.
Dr. Don Wuebbles, University of Illinois
A Sense of Hope
Our future depends on how we act to limit climate change.
Adaptation is not a choice – our choice is whether to adapt proactively or respond to the consequences.
Adaptation requires a paradigm shift, focusing on managing risks.
We can draw on our long history of responding to changing conditions in facing the challenges of climate change.
Dr. Don Wuebbles, University of Illinois
QUESTIONS?