GEO Midterm 2

Heat, Oxygen, and Hydrocarbons

**What three things are required for a fire to start?**

Oxygen

**In the photosynthesis reaction in plants, ________ is given off as a by-product of the reaction.**

Returned to the atmosphere

In effect, the solar energy stored by plants during their growth is _________________ during fire.

False

T/F: **Forests and woody shrubs can burn generating hot and intense wildfires, but grasslands never burn.**

Human Causes

**Most wildfires occur due to _________ NOT Natural Causes.**

Types of fuel, weather and topography

**The spread of fire depends on behavior within the fire itself and on __________________.**

(Fire) Up a slope

(Fire) **Fire burns faster ________________.**

All of these (wildfire)

**What are some construction and landscaping design methods to wildfire-proof your home?** 

Do not use wooden roof shingles

Do not build a wooden deck that extends over a hillslope

Do not plant shrubs close to the building

True

T/F: **Regional and local wind behaviors strongly influence the behavior of fires.**

True

T/F: **Many of the worst fires in history were accompanied by strong winds.**

Tornadoes

**The highest wind speeds of any weather phenomenon occur in ________________.**

**Thunderstorms cause damage**

Thunderstorms cause damage through: heavy rains, hail, and sometimes flash floods, lightning strikes, high-speed winds.

Florida

**Which state has the most lightning-related deaths?**

All of these (hail)

**Important requirements for hail to form are**

Strong updrafts to keep hailstones suspended while adding coatings of ice onto ever-growing cores

Upper-level cold air creating maximum temperature contrasts

None of these are correct.

Large thunderstorms with buoyant hot air rising from heated ground

**Hail storms** (which type)

(which type) **_________________ most frequently occur during late spring and summer in Texas, Oklahoma, Kansas, and Missouri.**

Tornadoes (which type)

(which type) **__________________ most frequently occur from April - July in Texas, Oklahoma, Kansas, Arkansas** .  

**The Enhanced-Fujita scale**

**_____________** quantifies tornado magnitude, based on maximum wind speed and damage

Hurricane

**Rank the following in order of** ***increasing*** **strength:**

Tropical disturbance, tropical depression, tropical storm, hurricane.

In the eye wall

**The strongest winds in a hurricane are _____________.**

**Hurricanes (which type)**

(which type) **Most frequently occur from August - October in Florida, Texas, Louisiana, North Carolina, South Carolina, Alabama, Georgia, Mississippi, New York, Massachusetts, and Virginia.**

Sun

**Energy from the __________ drives the Earth’s climate and weather processes.**

True

T/F: **Air moves from high pressure areas to low pressure areas.**

Left

**An air mass moving south in the Southern Hemisphere bends to the ____.**

**El Niñ**o

Warmer than normal surface water temperatures along the west coast of the Americas contribute to ___________ conditions and bring about higher-than-average levels of rainfall. **Characterized by heavy rainstorms in the western United States.**

**Differential Heating (fill in the blank)**

**Due to the tilt of the Earth on its axis, _____________ occurs resulting in the equatorial regions of Earth receiving more solar energy than the polar regions. (fill in the blank)**

Evaporation

**The process of changing from a liquid to a gas.**

True

T/F: **Jet streams are relatively narrow bands of high-velocity winds that flow from west to east at high altitudes.**

True

T/F: **The energy released by condensing a given mass of water is the same as that absorbed by evaporating the same mass of water.**

**La Niña**

**A typical ________ winter brings cold air with high rainfall to the northwestern United States and western Canada, but causes warming and below average rainfall in most of North America.**

Foreshock

A smaller magnitude earthquake that precedes the mainshock.

Mainshock

The largest magnitude earthquake during an earthquake sequence.

Aftershocks

Smaller earthquakes occurring after a large earthquake as the fault adjusts to the new state of stress.

Climate

The average pattern of weather in a region over a

long period of time. ex) Ice ages, multiyear droughts

Rising CO2

Weather

Pattern of weather variable over short time scales, day to day. ex) Rain, thunderstorms, Hurricanes, Tornadoes Sunshine or floods.

True

T/F: Climate helps to determine the type of weather in a given location at a given time of year.

What Drives Climate

Similar to plate tectonics, driving weather and climate requires a source of energy.

Unlike plate tectonics, the driver in weather and climate is an external source of energy.

Solar Energy

Earth’s climate is powered primarily from the Sun.

Arrives as:
• Visible light
• Infrared (heat)
• Ultraviolet (UV)

Albedo

Reflectivity is referred to this and typically accounts for 30% of solar energy.

Terrestrial Radiation

Earth radiates longer wavelength (infrared) radiation back into space.

Differential Heating

The difference in how land and water surfaces absorb heat. Less heating at poles because of: Lower density of rays

Steeper angle = more reflection.

Radiation

Energy that is transferred as electromagnetic waves, such as visible light and infrared waves.

Conduction

The direct transfer of heat from one substance to another substance that it is touching. Direct contact.

Convection

The transfer of thermal energy by the circulation or movement of a liquid or gas. Energy is transferred by the mass movement of molecules.

The role of water

71% of Earth is covered by water, 97.2% is found in Oceans. Regulating heat on earth by evaporation.

Hydrologic Cycle

The cycle through which water in the hydrosphere moves; includes such processes as evaporation. 24% of solar radiation received by Earth is used to evaporate water and begin.

True

T/F: Water has a very high heat capacity

Latent Heat

Heat required to change phase without changing temperature

Atmospheric Layers

Troposphere, stratosphere, mesosphere, thermosphere

Global air circulation

Polar, Ferrel, Hadley. Affected by the uneven heating of the earth's surface by solar energy, and the properties of air, water, and land. Easterlies and Westerlies.

Coriolis effect

Earth's rotation creates an apparent force. Deflects the paths of large, moving bodies to the right in the Northern Hemisphere, and two the left in the Southern Hemisphere.

Easterlies

Winds coming from the east and headed west.

Westerlies

Winds coming from the west and headed east.

Jet streams

High-energy, elongated flows that travel in narrow, elongated bands. Can reach speeds of \~250mph. Meandering path can bend and travel in all directions.

Anticyclones

Air sinks downward and spreads out

Cyclones

Air rises, cools and condenses, possible rainy weather.

Air masses

Large bodies of air that have relatively uniform temperature and moisture content at a given altitude. Tend to build in the Pacific and move eastward as a result of the prevailing winds, Coriolis effect.

Fronts

A boundary between two masses of air. Many weather events
(rain, etc) are associated with fronts at midlatitudes.

Orographic lifting

Cloud formation that occurs when warm moist air is forced to rise up the side of a mountain.

Surface circulation

Ocean Circulation is wind driven.

Deep ocean circulation

Ocean Circulation is density driven.

Moving air & weather

Northern hemisphere moves counter clockwise. Southern hemisphere moves clockwise.

Stages of a Thunderstorm

Early stage: rising cumulonimbus clouds.
Mature stage: Updrafts continue strong downdrafts operate.
Dissipating stage: Downdrafts dominate, cloud drafts sink.

Types of precipitation in downdraft

Rain, freezing rain, sleet, snow, hail are all \_____________.

Hail formation

Rain freezes and falls to a warmer part of air, condenses and refreezes to ice balls. Hail too large for cloud to hold falls to earth causing strong cold downdraft.

Lightning

Lightening is concentrated over land. Land heats up more quickly, leading to more convecting, upwelling. Abrupt electric discharge from cloud to cloud or from cloud to earth accompanied by the emission of light.

Recipe for a tornado

1) Low altitude, warm, moist tropical air from the Gulf of Mexico.
2) Cold, dry, fast moving air mass moving from Canada or Rockies, at mid

Single cell

Cool downdraft blocks upward flow of warm updraft.

Supercell

Shearing allows warm air to continue to rise into the central portion of the cell, while precipitation falls in the front.

Tornado Damage Mitigation

Protecting homes from high wind speeds: Reinforce/replace garage doors. Protect windows with storm shutters. Proper shingle placement. Remove at

Influence of El Niño

Fewer Atlantic Hurricanes, El nino present cool sea surface, drier summer. Correlation with increased wildfire activity in Australia.

Influence of La Nina

More Atlantic Hurricanes, El Nino absent, warmer sea surface, wetter summer. Correlation with increased wildfire activity in southwestern U.S.

Perfect recipe for Wildfire

Triple-digit temperatures, Extremely low humidity, Dense Vegetation.

Wildfire

Requires 3 things:
• Material to burn (Fuel)
• Oxygen
• Source ignition (Heat)

True

T/F: Combustion is the reverse of photosynthesis

Tropical rain forest

Very high productivity, Very rapid decomposition.

Temperate deciduous forest

High productivity, Rapid decomposition in summer.

Chaparral

High productivity, Low decomposition.

Desert Scrub

Low productivity, Low decomposition.

Ignition

The act of setting on fire or catching fire. Lightning Strike Density, correlation between lightning & wildfires.

Heat

Heat is carried via:
• Convection (air flow)
• Radiation (electromagnetic)
• Conduction/Diffusion

Tropical wave

Low pressure spawns showers and storms

Tropical depression

Sustained surface winds less than 39 mph

Tropical storm

Sustained surface winds 39+ mph

Hurricanes

Sustained surface winds 74+ mph

Saffir Simpson scale

Classifies hurricanes according to wind speed, air pressure in the center, and potential for property damage.

Hurricanes vs. Typhoons vs. Cyclones

Hurricanes: atlantic
Typhoons: hurricanes in PACIFIC
Cyclones: hurricanes in Indian ocean

Preheating

Water is removed from plants, wood, etc. Drying can occur due to nearby flames, drought.

Pyrolysis

Wood/Material breaks down to produce
flammable gases. Occurs at 615°F in wood. If oxygen is present, gases can ignite and combustion can begin.

Flaming combustion

Surface burns hot and fast. Greatest amount of energy release.

Glowing combustion

Solid wood burns, Lower temperature and more slowly than in flaming combustion. Combustion on the surface of a solid fuel in the absence of heat high enough to pyrolyze the fuel.

Spreading Fire

Wildfire can spread in different ways:
• Slowly along the ground (glowing combustion)
• Advance as a wall of fire (flaming combustion)
• Along the tree tops (crown fire)
Depends on Fuel, Wind/Weather, Topography and Behavior within the fire.

Fuel type common to California

Common to California: Evergreen shrubs, Highly flammable due to leaves coated in aromatic oils. Respond to fire in different ways such as sprouters, seeders, and germination.

True

T/F :Air masses descend to lower elevation regions. As air descends, it compresses and warms.

Fire suppression

Fire retardant Retardant: smothers fuels, reduces flammability.

True

T/F: Natural ~50 year fire cycle in So. California.

Wildfire Management

Open forests \= small wildfires. Growth of understory \= large wildfires.

Reasons Why Houses Burn

Location, Design, topography, and fire travels uphill.

Bad Design for fireproof house

Wooden porch overhanging slope, Dry grasses, woody shrubs, and trees.

Good Design for fireproof house

Concrete barrier, poor conductor, Succulent plants,
high water storage.

Dry

Chaparral, Juniper, and Scrub grow in relatively ______ environments where wildfires are the primary mechanism of plant decomposition.