Exam 4 Chapter 12 - 14 Review

Know what happens during each stage: pre-ignition, combustion, and (extinction)?

(No longer sufficient heat and fuel necessary to sustain fire)

Know what happens during each stage: (pre-ignition), combustion, and extinction?

(absorbs energy) 1. pre-heating - vegetation reaches a temp at which it can ignite (end of summer) 2. Pyrolysis - chemical process describing degradation of hydrocarbon molecules into smaller ones * produce first fuel gases that ignite

Know what happens during each stage: pre-ignition, (combustion), and extinction?

(heat and light released) begins with ignition (usually with multiple strikes of lightning), not all ignitions will result in a wildfire (veg. must be dry), ignition: is not a single process but occurs repeatedly... heat and light released three phases: -Ignition:Ignition is not a single process (Occurs repeatedly as wildfire moves) -Flaming: dominates early fire, rapid high temp, characterized by large amount of unburned material. -Glowing and smoldering: Takes place at lower temperatures (Does not require pyrolysis). Flame collapse and white ash is produced.

According to the model referenced in the textbook, what is the expected range of average world temperature increases in the 21st century?

2 and 6 degrees Celsius... plausible emissions scenarios...

Know and understand key terms in text (Asteroid).

710 meters to 1000 km in diameter. found in asteroid belt between mars and Jupiter. Composed of rock, metallics, and a combination.

Know and understand key terms in text (Fire regime).

A fire regime is the pattern, frequency, and intensity of the bush-fires and wildfires that prevail in an area over long periods of time. Fire regimes can change with the spatial and temporal variations in topography, climate, and fuel.

Know key terms, including (Greenhouse effect):

A phenomenon in which the atmosphere of a planet traps radiation emitted by its sun, caused by gases such as carbon dioxide, water vapor, and methane that allow incoming sunlight to pass through but retain heat radiated back from the planet's surface...

Know and understand key terms in text (Red flag warnings).

A red flag warning is a forecast warning issued by the United States National Weather Service to inform area firefighting and land management agencies that conditions are ideal for wild-land fire combustion, and rapid spread.

Know and understand key terms in text (Wildfire).

A wildfire, also known as a forest fire, vegetation fire, grass fire, brush fire, or bush-fire (in Australasia), is an uncontrolled fire often occurring in wild-land areas, but which can also consume houses or agricultural resources.

What is the net effect of volcanic eruptions on climate?

Aerosols and other particulates absorb solar energy and reflect sunlight back into space.

Know key terms, including (Aerosols/particulates):

Aerosols and other particulates absorb solar energy and reflect sunlight back into space... An aerosol is a suspension of fine solid particles or liquid droplets, in air or another gas. Aerosols can be natural or anthropogenic... Examples of natural aerosols are fog, dust, forest exudates and geyser steam... Examples of anthropogenic aerosols are haze, particulate air pollutants and smoke...

In which part of the world are the effects of global warming most evident?

Arctic / Polar regions

What material causes this effect of the net effect of volcanic eruptions on climate?

Ash... The gases and dust particles thrown into the atmosphere during volcanic eruptions have influences on climate...

Where do most Asteroids come from?

Asteroid belt between Mars and Jupiter... Asteroid belt, a region between Mars and Jupiter...

Approximately when did the Pleistocene "Ice Ages" begin, and when do scientists say they ended?

Began about 2 ma ago and ended about 18,000 years ago.

How do humidity and winds affect wildfire intensity?

Both wind and humidity = affect the moisture content of the fuel. Wind can remove the surface fuel moisture, which increases the drying of fuel. With more dry fuel, the fire burns more rapidly. When the humidity is high, it becomes harder for moisture to evaporate into the air. With low humidity, moisture evaporates into the air more quickly. A byproduct of low humidity is the surface fuel becoming dryer. Consequently, the wildfire becomes more intense when the humidity is low.

What is its general shape?

Bowl Shaped and an ejecta blanket is visible. bowl-shaped depressions upraised rim

How do these craters differ from volcanic craters?

Breccia is a rock type that naturally cemented together from shattered, broken and deformed rock. Breccia is only found in craters from ET impact. pressures and heating are far beyond in impact craters than what is seen in volcanoes

Know and understand key terms in text (Burns).

Burns =

What is our risk from asteroid impacts, high or low?

Calculating the risk is fairly high, but the chance of it happening in your lifetime, is actually quite low... The risks from impacts is relatively high, however the time period between events is so long that we shouldn't lose any sleep worrying about it...

Know which of these gasses can be generated by human activities (in other words, which are anthropogenic gases)?

Carbon dioxide, methane, nitrogen oxides, and chlorofluorocarbons.

What steps are we taking to prepare for possible ET impacts?

Categorization of comets and asteroids that cross the Earth's orbit are the first and foremost steps... Identify nearby threatening objects (space-watch), NEAT project (Near-Earth Asteroid Tracking)...

Know and understand key terms in text (Meteoroid).

Centimeters to 10 m in diameter. Most originate from collisions of asteroids or comets.

Know the difference between weather and (climate)?

Climate: characteristic atmospheric conditions or region over long periods from years to decades... For example: you can expect snow in the Northeast in January and humid in the Southeast in July. Example: Tropical climates are hot and can have a lot of precipitation. Polar climates are the coldest of all of Earth's climate types. ... They experience all four seasons with warm summers and mild winters... Think about it this way: Climate is what you expect, weather is what you get...

Know and understand key terms in text (Combustion).

Combustion is a chemical reaction that occurs between a fuel and an oxidizing agent that produces energy, usually in the form of heat and light.

What are the common causes of mass extinctions?

Common causes of mass extinctions are relatively rapid climate change that can be triggered by plate tectonics, volcanic activity, or extraterrestrial impact.

Know key terms, including (Anthropogenic):

Concentration of certain greenhouse gases has increased due to human activities... The Anthropocene defines Earth's most recent geologic time period as being human-influenced, or anthropogenic, based on overwhelming global evidence that atmospheric, geologic, hydrologic, biosphere and other earth system processes are now altered by humans...

Which is usually most difficult to extinguish?

Crown fires are nearly impossible to stop.

Review the negative impacts of wildfires.

Deforestation can have a negative impact on the environment. The most dramatic impact is a loss of habitat for millions of species. Eighty percent of Earth's land animals and plants live in forests, and many cannot survive the deforestation that destroys their homes. Deforestation also drives climate change. Forests are a vital element in the Earth's ecological balance, economy, biodiversity, water resources and air purity. On the other hand, forests are confronted with various threats - one of them being fires.

What were the key conclusions of the IPCC report in 2000?

Discernible human influence on global climate... Warming is now occurring... Mean surface temp will likely increase by 1.5-4.5 degrees C during 21st century...

Know and understand key terms in text (Dry ravel).

Dry ravel is a general term that describes the rolling, bouncing, and sliding of individual particles down a slope and is a dominant hill-slope sediment transport process in steep arid and semiarid landscapes.

Know and understand key terms in text (Meteor).

Dust and sand sized grains. Frictional Heating produces light

How does an impact crater form?

Ejecta blanket is the rim that is overlain by a layer of debris. high velocity, energy, pressure, and temperature

Know and understand key terms in text (Hydrophobic layer).

Extremely hot fires that scorched dry, coarse soil and leaves non wet-table or water-repellent layer. This layer increases runoff and erosion because the ground now lacks vegetation to anchor...

What weather factors are considered?

Fire danger ratings combine information about fuel conditions, topography, weather, and risk of ignition to assess the wildfire hazard. Because fire is a complex product of many factors, as described above, a changing climate could affect the frequency and severity of wildfires in a variety of ways. Temperature is one of the most important. In a warmer atmosphere, water is more likely to evaporate from vegetation, making the landscape more fire prone.

Which is most important for driving the ice age cycles?

Fluctuations in the amount of insolation (incoming solar radiation) are the most likely cause of large-scale changes in Earth's climate... In other words, variations in the intensity and timing of heat from the sun are the most likely cause of the glacial/interglacial cycles.

Where is wildfire danger the greatest?

Geographically, Alaska and the western contiguous US, in the Canadian Rockies, and in a belt that extends from Canada's Yukon territory southeast. The geographic region at greatest risk for wildfires shifts from year to year due to factors such as weather conditions and fuel availability.

What clues led scientists to believe that an ET impact cause the K-T mass extinction?

Geology of K-T Boundary Walter and Luis Alvarez measured concentration of iridium in clay layer at K-T boundary in Italy Concentration of iridium much higher than in most of the crust Iridium deposits indicate that layer formed quickly Fossils found below layer were not found above Extinction probably caused by single asteroid impact Alvarez did not have a crater to prove the theory Crater was identified in 1991 in Yucatan Peninsula Diameter approx. 112 mi Nearly circular Possibly as deep as 18-25 mi Slumps and slides filled crater Drilling finds breccia under the surface Glassy, indicating intense heat Sixty-five million years ago, more than three-fourths of all plant and animal species living on Earth became extinct. This event is known as the K-T mass extinction because it occurred at the boundary between the Cretaceous (K) and Tertiary (T) time periods. The most famous group of animals to perish was the dinosaurs.

What are the most abundant gases present in our atmosphere (Oxygen)?

Given the abundance of oxygen and silicon in the crust, and is the most abundant minerals in the earth's crust are the silicates...

Know key terms, including (Glacier):

Glaciers form where the accumulation of snow and ice exceeds ablation...

What are the different wildfire types?

Ground fires surface fires crown fires.

Which combination of humidity and wind would lead to the most intense fire?

Humidity = wildfires burn more vigorously when relative humidity is at its lowest point, generally during mid afternoon. Winds = influence spread, intensity and form of a wildfire... strong winds and changing wind conditions help a fire preheat unburned fuel in the surrounding area. They can also carry burning embers away and ignite spot fires.

Know and understand key terms in text (Comet).

Ice (water or co2) and rock. Have glowing gas and dust tails when near the sun. Originate in Oort cloud (long period) or in the Kuiper Belt (short term).

Know and understand key terms in text (Meteorite).

If the object strikes earth. Pieces of meteorites and asteroids.

Know and understand key terms in text (Impact crater).

Involve high velocity, energy, pressure, and temperature. Kinetic energy of impact produces shock wave into earth. compresses, heats, melts, and excavates materials. Rocks become metamorphosed

Know the primary greenhouse gases and their relative contribution to the greenhouse effect (Carbon dioxide (CO)?

Is the most significant anthropogenic.

Know which of these gasses can be generated by human activities (in other words, which are anthropogenic gases...) (Fluorinated gases ("F gases")?

Key sources are industrial processes. F-gases are even more potent per gram than nitrous oxide.

Know which of these gasses can be generated by human activities (in other words, which are anthropogenic gases...) (Methane (ch4)?

Key sources include agriculture (especially livestock and rice fields), fossil fuel extraction and the decay of organic waste in landfill sites.

Know which of these gasses can be generated by human activities (in other words, which are anthropogenic gases...) (Nitrous oxide (n2o)?

Key sources include agriculture (especially nitrogen-fertilized soils and livestock waste) and industrial processes.

What are the geologic clues indicating that an impact has occurred?

Landforms = Impact craters Rocks = Breccia, Shatter Cones, Microspherules Minerals = Shocked grains, High-pressure quartz Chemical signature

How are objects in the solar system classified?

Large solar bodies = stars, planets, dwarf planets, and moons. Small solar system bodies = meteors, meteoroids, asteroids, and comets. Objects are arranged by diameter and composition Defined as "any of various celestial bodies, such as asteroids and comets, that orbit the sun and are not classified as either planets or dwarf planets."

Why don't we see more impact craters on Earth?

Most impacts are in the ocean where craters are subsequently buried by marine sediment or destroyed by plate tectonic processes.

Understand the three primary natural causes for climate change = solar forcing, volcanic forcing, and the (Milankovitch cycles)?

Natural variations in the intensity of solar radiation that reaches earth's surface that recur at approx. 20,000-40,000 and-100,000 year intervals.

What are the most abundant gases present in our atmosphere?

Nitrogen, Oxygen, and Argon

Know the primary greenhouse gases and their relative contribution to the greenhouse effect (Nitrous oxide (n. 2o)?

Nitrous oxide is emitted during agricultural and industrial activities, as well as during combustion of fossil fuels and solid waste.

Know and understand key terms in text (Airburst).

Object explodes in atmosphere 7-31 miles up

What is "duff" composed of, and where is it found?

Organic matter in the soil, Partially decayed leaves, twigs, etc. And found accumulates below leaf litter, above mineral soil (ground fuel)...

Where do most Comets come from?

Outside solar system in the Oort Cloud Originated far out in the solar system, beyond Neptune.

What are the three stages of wildfire development?

Pre-ignition Combustion Extinction

Know and understand key terms in text (Prescribed).

Prescribed =

Know key terms, including (Proxy data):

Proxy data is data that paleoclimatologists gather from natural recorders of climate variability, e.g., tree rings, ice cores, fossil pollen, ocean sediments, coral and historical data...

Know key terms, including (Climate forcing):

Radiative forcing of climate forcing is the difference between insolation (sunlight) absorbed by the Earth and energy radiated back to space...

What is a Red Flag Warning?

Red flag warnings are used when extreme fire conditions either are occurring or will take place in less than 24 hours.

Know and understand key terms in text (Sediment flushing).

Sediment flushing =

Know and understand key terms in text (Mass extinction).

The extinction of a large number of species within a relatively short period of geological time, thought to be due to factors such as a catastrophic global event or widespread environmental change that occurs too rapidly for most species to adapt.

Know which of these gasses can be generated by human activities (in other words, which are anthropogenic gases...)(Carbon dioxide (co2).?

The key source of co2 is the burning of fossil fuels such as coal, oil and gas, though deforestation is also a very significant contributor.

Know the primary greenhouse gases and their relative contribution to the greenhouse effect (Methane (CH)?

The largest contributions of greenhouse gases in agriculture come from methane and nitrous oxide. It also is emitted during the production and transport of coal, natural gas, oil, and livestock

What elements are necessary for fire to burn?

The triangle illustrates the three elements a fire needs to ignite: heat, fuel, and an oxidizing agent (usually oxygen). Oxygen, fuel and heat

Know the primary greenhouse gases and their relative contribution to the greenhouse effect (Water vapor (h2o)?

The warmer it becomes, the more water is sucked out of the ground and is transformed, this further accelerating the warming process...

Know the primary greenhouse gases and their relative contribution to the greenhouse effect (Ozone (O), Chlorofluorocarbons (CFCs), Hydrofluorocarbons (incl. HCFCs and HFCs), and Fluorinated gases) ?

These gases are typically emitted in smaller quantities, but because they are potent greenhouse gases, they are sometimes referred to as High Global Warming Potential gases ("High GWP gases").

How does radiation from a wildfire help it keep burning?

This transfer of heat causes the fire to grow and to spread to other areas. Wildfires transfer heat primarily through convection, but also through radiation- which generates radiant heat. Convection/radiant heat increases the surface temperature of the fuel. Wildfires transfer heat primarily through convection, but also through radiation- which generates radiant heat. Convection/radiant heat increases the surface temperature of the fuel.

How might we try to prevent one (ET impact)?

To prevent one we would need to either blow it up in space, evacuation, change the orbit of asteroid. Blowing it up in space, change orbit of asteroid, or evacuation To prevent one we would need to either blow it up in space or divert it away from earth...

What are the key factors that determine whether a region is prone to wildfires?

Topography (south side mountain, long grassy plains) Low humidity = greater fires, Ambient temperature/wind (drought equals dry easy to use fuel and wind supplies oxygen).

Understand the three primary natural causes for climate change = solar forcing, (volcanic forcing), and the Milankovitch cycles?

Volcanic eruptions hurl amounts of aerosols (particulates) into the air which reduces solar radiation to the earth's surface-reflecting incoming UV and keeping the planet cooler...

Know the primary greenhouse gases and their relative contribution to the greenhouse effect?

Water vapor, Carbon dioxide, Methane, Nitrous oxide, Ozone, Chlorofluorocarbons, Hydrofluorocarbons, and Fluorinated gases

Know the difference between (weather) and climate?

Weather: transient condition, short term, and what you see outside on any particular day. Example: Weather can change from minute-to-minute, hour-to-hour, day-to-day, and season-to-season. Think about it this way: Climate is what you expect, weather is what you get...

What is the definition of a forcing variable?

a cause or process that can influence global temperature changeThey change the global energy balance, which forces the climate to change. (Solar emission, volcanic eruption, and anthropogenic gases)...

Know key terms, including (Interglacial):

a geological interval of warmer global average temperature lasting thousands of years that separates consecutive glacial periods within an ice age...

Know key terms, including(Glacial):

an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances...

Know and understand key terms in text (Pyrolysis).

breaking down carbon into a chemical change...

Know key terms, including (Abrupt climate change):

occurs when the climate system is forced to transition to a new climate state at a rate that is determined by the climate system energy-balance, and which is more rapid than the rate of change of the external forcing...

Know and understand key terms in text (Wild-land-urban interface (or WUI)).

refers to the zone of transition between unoccupied land and human development...

Know key terms, including (Global Dimming):

decrease in the amounts of solar radiation reaching the surface of the Earth... (The cause) It is thought that global dimming is probably due to the increased presence of aerosol particles in the atmosphere caused by human action... Aerosols and other particulates absorb solar energy and reflect sunlight back into space... The pollutants can also become nuclei for cloud droplets.... (Definition) - Global dimming is defined as the decrease in the amounts of solar radiation reaching the surface of the Earth... The by-product of fossil fuels are tiny particles or pollutants which absorb solar energy and reflect back sunlight into the space...

Know key terms, including (Global warming):

describes the current rise in the average temperature of Earth's air and oceans. Global warming is often described as the most recent example of climate change.

What primary assumption is this based upon?

discernible human influence on global climate... warming is now occurring... mean surface temp by 1.5%-4.5%...

Review the carbon cycle. How is carbon naturally removed from the atmosphere?

from atmosphere to plants in photosynthesis... Vegetation, Forest, land and the ocean all naturally remove carbon naturally from the atmosphere...

What is the ocean conveyor belt, and what effects does it have on northern Europe?

global circulation of ocean... water warmer water... Global circulation of ocean water. Contributes to changes in climate. Changes in arrangement of continents greatly affects ocean circulation and thus climate...

Know which of these gasses can be generated by human activities (in other words, which are anthropogenic gases...) (Chlorofluorocarbons (CFCs)?

have no natural source, but were entirely synthesized for such diverse uses as refrigerants, aerosol propellants and cleaning solvents.

Know key terms, including (El Nino):

is a climate pattern that describes the unusual warming of surface waters in the eastern tropical Pacific Ocean.

Know and understand key terms in text (Near-Earth objects (NEO).

is any small Solar System body whose orbit can bring it into proximity with Earth.

What are the most abundant gases present in our atmosphere (Nitrogen)?

is not stable as a part of a crystal lattice, and is enriched in the atmosphere relative to oxygen...

What are the most abundant gases present in our atmosphere (Argon)?

is the third-most abundant gas in the Earth's atmosphere

How does mountainous topography affect wildfire intensity?

makes it easier/faster to spread wildfire, winds preheat fuels upslope, speeds preignition upslope the moisture content of fuel is influenced based on location air circulation, prevailing winds Steep slopes

What is a mass extinction?

mass extinctions are characterized as the sudden loss of large numbers of plants and animals relative to the number of new species being added.

How do modern and past federal policies on wildfire management differ?

now there's fire danger alerts and warnings "defensible space"

Understand why graphs of atmospheric CO2 concentrations can have a "sawtooth" look associated with the seasons of the year?

spring means plants need more co2 winter co2 are higher

Understand why graphs of atmospheric co2 concentrations can have a "sawtooth" look associated with the seasons of the year?

spring means plants need more co2... winter co2 concentrations are higher...

Understand the three primary natural causes for climate change = (solar forcing), volcanic forcing, and the Milankovitch cycles?

variation in solar radiation (heat flow) can cause climate change.