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Duane Friend Extension Educator University of Illinois Extension If you would like a copy of this power point Send me an email at: [email protected] Weather Why do we have seasons? How the atmosphere works Wind and air pressure Clouds Stormy Weather Some basic forecasting by looking at weather 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 http://www.physicalgeography.net/ The more Direct the Sun Angle, the more concentrated the Heating http://www.physicalgeography.net 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 In general, temperature decreases with elevation in lower levels 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 Incoming Solar Radiation http://www.physicalgeography.net/fundamentals/7f.html What comes in eventually goes out 30 + 6 + 64 = 100 http://www.physicalgeography.net/fundamentals/7i.html 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. Air Pressure and Winds Air pressure at sea level is almost 15 pounds per square inch Air pressure decreases with height Air pressure varies due to temperature and dynamic forces in atmosphere http://www.physicalgeography.net/fundamentals/7d.html Air Pressure variations Thermal- warm surface temperatures = lower pressure Cold surface temperatures = higher pressures Dynamic- Rising air = lower pressure Sinking air = higher pressure http://www.physicalgeography.net/fundamentals/7n.html Air pressure and wind Winds blow from high to low Earths rotation changes this a bit at the surface http://www.physicalgeography.net/fundamentals/7n.html Large Belts of High and Low Pressure (Courtesy NASA JPL) 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 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: Cool temperatures, wind from southeast or south, pressure decreasing, increasing cloudiness with potential for extended period of precipitation After warm front passage: Warmer temperatures, wind shift to southwest, pressure remains steady, skies clear Weather Associated with Fronts Prior to cold front passage: Warm/moderate temperatures, relatively clear skies with increasing cloudiness in vicinity of front. Winds out of south, west, or southwest While front is passing: drop in air pressure, brief intense precipitation After passage: Cool/cold temperatures, pressure increases, skies clear, winds from north or northwest 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 came from the Plymouth State University Meteorology Program Violent Weather 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 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 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 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 Dryline/Supercell development Dryline develops in warm sector, between cold and warm front Hot, dry air overrides warm, moist air, creating a cap cT air cT “cap” prevents mT air from rising mT air Once Cap is Punched Through Air is extremely unstable- will ascend at upwards of 150-200 miles per hour Rotation develops due to wind shear 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 leaderstarts 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 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 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 Safety As of late August, there have been 20 confirmed lightning deaths in 2011 in the US. 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 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) Predicting Weather Can use things like clouds, wind direction, pressure to make short term predictions 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 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 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. Photo courtesy USGS 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. Short Faced Bear Courtesy Illinois State Museum Muskox about to be Eaten Courtesy Illinois State Museum Movement of vegetation Starting about 14,000 years ago, boreal forests moved north as the climate warmed, replaced to the south by deciduous forests. Grasslands replaced forests as climate continued to warm from about 10,000 to 8,000 years ago 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 Map of Prairie Peninsula by Edgar Transeau Prairie illustrated in dark brown What caused the Prairie Peninsula? Extreme droughts periodically have occurred in this area Forested areas have moisture more evenly spread throughout the year Does not explain it entirely What Else? The area is mostly flat Periodic fires kept tree growth in check Fires ignited by Lightning, humans Human induced Prairie Fires The Miami’s hunt them at the end of autumn in the following manner: When they see a herd they gather in great numbers and set fire to the grass everywhere around these animals except some passage which they leave on purpose and where they take post with their bows and arrows. The buffalo, seeking to escape the fire are thus compelled to pass near these Indians, who sometimes kill as many as a hundred and twenty in a day, all of which they distribute according to the wants of the families . . .(Hennepin 1880)." From Illinois Dept. of Natural Resources Average Annual Precipitation Average Annual High Temperature Average Annual Low Temperature Average Annual Snowfall Average Growing Season Climate and soils Illinois’ recent glaciation (yes I said recent), cold winter, plus prairie grass coverage over most of the state has created highly productive soils. Soils and Climate Cold winters inhibit microbial decomposition of soil organic matter Prairie plant root systems were massive and fibrous Newly formed soils have a lot of minerals/nutrients in A horizon = lots of organic matter and nutrients for plants! Microclimates affected by landforms Future Climate in IllinoisWhat will it be? Climates naturally fluctuate Human created inputs affect this change How to predict what climate will become Variations Occur on Smaller Scales Human Induced Climate Change Increase in Greenhouse gases leading to Global Warming What are the consequences? That’s the question! Computer modeling used to predict what may happen Natural “Greenhouse” Effect Adapted from NOAA Global Warming An increase in greenhouse gases increases the retention time of heat within the atmosphere Global Warming When additional greenhouse gases are added to the atmosphere, this increases the length of time it takes for heat to escape, thus raising temperature in the lower atmosphere = Global Warming Greenhouse gases Carbon Dioxide Methane Nitrous Oxides Chloroflorocarbons How the Earth Reacts to more GHG’s Cold ocean waters absorbs some of the increase in atmospheric CO2 (but only so much) Methane is cleansed from the atmosphere, but does not do this as quickly as it is produced Nitrous oxides have long atmospheric lifetimes- up to 120 years. It is eventually dissociated by UV radiation in the stratosphere Whats the Result Levels of Atmospheric Greenhouse Gases are rising. What are the consequences? Rising sea levels? Weather pattern changes? Ocean circulation changes? IT’S NOT JUST A THEORY---THE EARTH HAS TO REACT TO THE CHANGE IN GREENHOUSE GASES Earth’s history provides important information on global warming. Courtesy Dr. Jim Hansen, Columbia University Surface Melt on Greenland Melt descending into a moulin, a vertical shaft carrying water to ice sheet base. Source: Roger Braithwaite, University of Manchester (UK) Illinois State Water Survey Illinois State Water Survey From :Climate Change Impacts on the United States The Potential Consequences of Climate Variability and Change By the National Assessment Synthesis Team, US Global Change Research Program 36 Mild Winters = SOM loss Warmer temperatures would allow soil microbial activity to continue to decompose soil organic matter, instead of shutting down. Study of soil carbon and temperature in England A recent study of England's soils suggests they have been losing carbon at the rate of four million tons a year for the past 25 years In the past 25 years the average temperature has increased by almost 1 degree Fahrenheit. Warmer soils are believed to have encouraged greater microbial activity and more rapid decomposition of soil organic matter. Bellamy, P. H., and Co-authors, 2005: Carbon losses from all soils across England and Wales 1978-2003. Nature, 437, 245-248. SOM and precipitation In general, soil organic matter is increased with elevated levels of soil moisture. This is the result of greater biomass production, which provides more residues, and thus more potential food for soil microbes. Double Whammy? Milder winter = more SOM decomposition More drought = less SOM production How would increased global warming affect soil organic matter and carbon cycling? Microbial activity greatly influenced by moisture and temperature Great Lakes species favoring cool climates are shifting their ranges up in elevation and to the north. Plant and animal communities adapted to warm climates are expanding. Cool adapted tree species such as sugar maple and paper birch are projected to lose habitat in the U.S. and shift largely to Canada. More southern species such as oaks, hickories and pines may see an expansion of potential habitats Source: National Park Service Arctic Change: Future loss of Arctic sea ice could result in a loss of 2/3 of the world's polar bears within 50 years. Source: U.S. Geological Survey www.usgs.gov/newsroom/sp ecial/polar%5Fbears/ Images: Sea Ice: Claire Parkinson & Robert Taylor Polar Bears: Unknown 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 Distribution of fish will change according to the temperature of water. Warm water fish such as bass will expand northward, while trout and other cold water fish will decrease 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. What makes “Natural” Climate Change Occur http://www.physicalgeography.net/fundamentals/7y.html 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 Summary Climate is in constant change If change is rapid, species may not be able to adapt If we can’t manage the change, we can only manage the consequences