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Tropical cyclones
- Once on land, lose power
- Low pressure system with winds exceeding 74mph
- Use warm water to energize wind and waves
- Warm humid unstable air
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Tropical disturbance
- Definite area of surface low pressure; patches of clouds
- variable low
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Tropical depression
- Gale forse, organizing circulation; light to moderate heat
- 39 mph
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Tropical storm
- Closed isobars; definite circular organization; heavy rain and is assigned a name
- 39-73 mph
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Tropical cyclone
- circualation, closed isobars/ Heavy rain, storm surges; tornadoes
- Greater than 75mph
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Eye
The center of a tropical storm or hurricane, characterized by a roughly circular area of light winds and rain-free skies. An eye will usually develop when the maximum sustained wind speeds exceed 78 mph. It can range in size from as small as 5 miles to up to 60 miles, but the average size is 20 miles. In general, when the eye begins to shrink in size, the storm is intensifying.
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Eyewall
An organized band of convection surrounding the eye, or center, of a tropical cyclone. It contains cumulonimbus clouds, intense rainfall and very strong winds.
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Rain bands
- Most intense rains-2 inches of rain per hour
- beyond rain band- subsiding air
- Clean cut break
- How it works:
- Numberous thunderstorms in bands that spin around
- Convergent air towards the center
- Eye is very clear
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Hurricanes origin
- main energy: latent heat released by condensation
- landfall wekaens the storm
- not associated with fronts
- weaker high-altitude wind= stronger hurricanes
- centers warmer then surroundings
- winds weaken with height
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Coriolis effect
- none at equator
- A force per unit mass that arises solely from the earth's rotation, acting as a deflecting force. It is dependent on the latitude and the speed of the moving object. In the Northern Hemisphere, air is deflected to the right of its path, while in the Southern Hemisphere, air is deflected to the left of its path. It is greatest at the poles, North and South, and almost nonexistent at the equator.
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Saffir-Simpson Scale
A measure of hurricane intensity on a scale of 1 to 5. The scale categorizes potential damage based on barometric pressure, wind speeds, and surge.
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Naming
- Named using the alphabet and the Greek alphabet if necessary
- Alternate male and female names
- 6 lists
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Hurricane hunters
- 53rd weather reconnaissance squadron of the us air force
- NCAR GPS Dropsond gets wind speed, pressure, temp
- What category
- How organized
- Is it getting stronger
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Cape Verde type of hurricane
- Northwest Africa
- Easterly wave is a disturbance
- Develops in the trade winds
- Very long, north to south
- On right hand side of axes-convergence and clouds
- Left hand side- divergence and less clouds
- Blown westward by the trade winds
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Hurricane Paths
- Difficult to predict
- Adjust to other high and low pressure systems
- Trade winds
- Coriolis effect
- Bermuda high
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Bermuda high
- Small: hurricanes stay over Atlantic ocean
- Large: guides hurricanes toward eastern coast moved southward: guides hurricanes into the Caribbean sea and gulf of Mexico
- If it slips southward: will push hurricane paths into golf
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Caribbean sea and gulf of mexico type hurricanes
- Originate at the intertropical convergence zone
- Daily thunderstorms- organizes as it moves away from the equator
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Enso
- El Niño bring eastward blowing winds that disrupt storms
- Slow down the storm
- La Nina conditions westward blowing trade winds aid in growth of hurricanesIntensify storm
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Storm Surge
- Rising of local sea levels
- Winds from approaching storm
- Sea water builds beneath the eye- low pressure in eye
- Wind speed vary along the coastline which impact the water rushing on shore
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Flooding
- Massive amounts of water vapor exist in hurricane
- Moving on land the energy decreases
- falls as precipitation
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2005
- most active season on record
- damages exceeded $115 billion and 1900 deaths
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Hurricane Katrina
anticipated for decades- 1 in 4 did or could not evacuate
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Models-Katrina
- NOAA showed levees would not hold a category 3 storm
- katrina raised lake 3 meters- somewhere between 7 and 9 meters
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City subsiding- Katrina
lower 20 feet- the levees basically have made part of the city a bowl
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Social aspects Katrina
- 85% of all counties are less socially vulnerable
- widening gap between rich and poor
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Fire Triangle
- we always have oxygen ready
- fire can only begin when fuel, oxygen and heat are present in the right combination
- extra wood debris on ground can cause fire
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Fire
Rapid combination of oxygen with carbon, hydrogen and other elements of organic material in a reaction that produces flames, heat and light
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Fuel: Ladder
- Any combustible material can be used as fuel source
- Ladder fuel: understory of slash and shrubs allows fire to spread up into tall trees
- When you have this situation usually you get major fires
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Fighting fire
- When add water your removing the heat
- fire resistance: black oxygen from contacting the plant
- Firefighters cause another fire to burn in front to achieve a back fire
- Can slow down fire
- We use purple k to stop chemical reaction by smothering
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Stages of fire
- Preheating: water expelled from fuel by nearby flames, drought, hot summer day
- Pyrolysis: when the chemical structure of solid wood breaks apart and yields flammable hydrocarbon vapor- You can get tar or residue which can add to your burn
- Oxygen gets gasses to ignite, add in combustion then you get fire
- Flaming combustion: stage of greatest released energy
- Glowing combustion: wood itself burns slowly at lower temp. without flames
- These steps happen simultaneously when a forest fire is going on
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Spread of fire
- Fuel: (Eucalyptis)Some forest have more oil, Grass that moves quickly through area
- Topography: becomes an issue because fire travels upward. Heat rises and drys out tress above it
- Wind: helps supply energy, can bend fire, fire brands and embers
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Type of fire
- 1: convection column coming off flame
- weak winds
- moving slowly, easy to contain
- 2: dirt smoke
- tilt of fire, moving uphill
- easier to set things on fire
- 3: strong winds. Convection column
- can get a fire tornado
- fire can create own winds and own fire- move quickly
- 4: blowing embers
- 5: winds at different speeds at different heights
- 6: large wind blowing fire horizontally across ground
- blowing smoke and hot air across
- 7: topography boundary, going up hill, can go quickly
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Fuels of fire
- Grasses
- shrubs
- shapperel
- forest
- litter
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Local and Foehn Winds- fire
- Foehn winds: high pressure air mass that spills over mountain range and descends as a warm dry wind toward a low pressure zone
- Taking wind that will make it dryer and dry out conditions
- Chinooks, Sanat anna,Diablo, Borth winds, East winds All can make very warm and dry & Fast wind speeds
- Local winds: land and sea breeze, slope winds & doesn’t have to be surrounded
- When ground heats up and air flows up slope at night it gets colder and goes downslope·
- valley winds: Similar effect to slope wind
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Flying embers:
- Can be huge threat
- Clear a fire line cutting off fuel- but one ember can spark a fire in front of the line
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Home design- fire
- flames can burn thourgh vegetation and along a fence
- can generate enough radiant heat to ignite the exterior or curtains
- firebrand and embers can be dropped on or next to your house
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Fire supression
- 20th centuray: all fires were to be put out as quickly as possibly
- tactics and equipment improved
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Yellowstone
- about 15 fires a year
- human caused
- dry winters
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Prescribed fires
- Government paid billions to those who lost houses
- Trying to urge natural fires to take place
- They’ll set up so they can take care of it
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Fossils:
Evidence of former life: early understanding of extinction
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Extinction
- Inability to adapt to the changes in physical, chemical and biological conditions
- average life span of species 4 million years
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Possible causes for mass extinction:
- Plate tectonics: sea level drop/rise
- Changes in seafloor spreading rates: more rapid spreading
- mid-cretaceous
- Sea level changes: bigger glaciers, lower sea level
- Number and size of continents: pangea
- Volcanic causes: flood basalt
- Changes in atmospheric pressure: flood basalt eruptions, sub-sea eruptions, continental eruptions
- Ocean compostion: ocean is chemically connected to dissolve salts, bottom sediments, continents, atmosphere
- Extra-terrestrial: wildfires, acid rain, tsunami, dust cloud
- Biological causes: species-area effects
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Cretaceous- fossils
- North american heartland covered with heard of dinosaurs and flowering plants
- over 35% of genera and 65% of species went extinct
- sea level fall, deccan traps flood basalt, chicxulub impact
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Long-term species
- Horeshoe crabs
- sharks
- conifers, ferns, horsetail and scouring rushes
- norfolk pine, ginko balboa, metasequoia and sago palm
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Quaternary extinctions
significant extinctions of large-bodied mammals in last 1.5 million years, during glacial advances and retreats
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Hot & cold: Hypothermia
- Core temperature drops below the required temp for normal metabolism and body temp- 98.6F
- Wind chill
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Hot & Cold: Hyperthermia
- Heat- (heat stroke) biggest killer of all sever weather
- Elevated body temperature
- occurs when body produces or absorbs more heat then it can dissipate
- Dont have cooling effect because moisture is in air and on body
- Heat index- humidity+temperature
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Hot & Cold: Snow
- Windchill: Temp and windspeed could be factors
- Nor easters: Low pressure system- where you have colder air and warm humid air hits cold air
- Dumps out as snow or rain
- Blizzards: Strong cold winds filled with snow
- Whiteout- cant distinguish ground from sky. Snow on ground and air
- Lake effect snow: typically beginning of winter. Lakes have to be warmer then air. Lake not frozen
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Hot & Cold: Urban heat island
- Impervious surfaces: heat up and hold heat longer then natural surfaces
- Wont cool down as fast
- Marked by higher nighttime temp
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Impacts scars- the moon
- Impact scars: surface of the moon
- Some with diameters as large as 100s of miles
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Cosmic Dust
Smallest meteroid unaffected by atmosphere
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Shooting star
Sand grain sized debris
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Meteroids
- Outside will burn off, still left with the inside
- They will be glazed and have black outer crust
- When they fall violently, it will compress the air and make a sonic boom
- Friction can raise the temperature: which can also slow down the meteoroid
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Asteroid belt
- a region between the inner planets and outer planets where thousands of asteroids are found orbitting around the Sun.
- Hits between the 4 rocky planets (inner) and 4 gassiest planets (gassy)
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Asteroids
- Four small inner planets and four large outer planets
- all asteroids would have formed a planet half the size of the moon
- for the most part they stay on path
- can hit each other though- it’ll leave 2 craters
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Comets
- Short period- 200 yr orbit
- Long period- longer then that
- Kuiper belt, Oort cloud
- Not necessarily coming on a nice path—could be an angle
- Comet tails will always face away from the sun- dscribed as dirty snowballs
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Craters:Simple
Pot hole divit
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Craters: Complex
- 2 rings
- Central uplift and a collapsed rim
- Size of meteoroid doesn’t make crater- vaporizes with heat around it which makes crater larger
- Crater size bigger than the object that creates it
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K/T boundary
Layer marked by high quantity of iridium found in limestone layer
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Problems with space objects in atmosphere
- Earthquakes
- Wildfires
- Acid Rain
- Dust
- Tsunami
- Steam
- Limestone
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Risk from space objects
- Bigger than 1km in diameter
- 90% are near-Earth asteroids, short-period comets
- 10% intermediate or long period comets
- 2,000 near-earth objects 25-50% will eventually hit Earth
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