Lecture 7: Earth's Energy Balance Flashcards
Atmosphere compostion
78% Nitrogen, 21% Oxygen, 1% water vapour/CO2
Troposphere
First layer ~11km, all weather confined here
Stratosphere
second layer, contains ozone layer
Cloud Prefix Cirro-
High cloud
Cloud Prefix Alto-
Mid-level Cloud
Cloud Prefix Atrato-
Low Cloud
Cloud Suffix -cumulus
puffy
Cloud suffix -stratus
flat
Nimbostratus
Prolonged precipitation
Cumulonumbus
Heavy precipitation: dangerous, has lightning
Pressure
Force exerted on Earth’s surface by weight of air molecules
Low Pressure
air moves counterclockwise, rises -> clouds, rain
High Pressure
air moves clockwise, sinks -> clear skies
Fronts
Boundary between two air masses
Cold front
Cold dense air undercuts warm air: more violent
Warm Front
Less dense warm air overrides cold air: more gentle
Hail
- storms with very tall clouds
1) updrafts push water up
2) droplet develops ring of ice each time it goes through cloud
3) Falls once it is heavy enough
Lightning
- Spark of electricity occuring in a cloud, majoirty within the cloud
- heated air causes air to expand, causing shockwave = thunder
- atmosphere can refract thunder, making it inaudible
Tornado
-rotating column of air touching ground that is formed within a supercell thunderstorm
~ 300 m wide, last less than 30 mins
-travel SW-> NE 50km/hr
-most common in spring
Funnel Cloud
-Rotating column not touching the ground
Life Cycle of Tornado
1) Organizational Stage: wind shear causes rotation, funnel cloud protrudes
2) Mature Stage: damage at this stage
3) Rope Stage: tornado stretches out and weakens
Wind Shear
Change in wind speed/direction over horizontal/vertical distance
Enhanced Fujita Scale
tornado classified EF0-EF5 based on wind speed
Tornado Alleys
Flat areas in Canada (SW ontario) and the US (kansas, Oklahoma) where air masses commonly collide
Joplin Tornado
May 22 2011
- EF5 tornado with 162 deaths in Joplin
- most costly: 2.2 billion
Goderich Tornado
Aug. 21st 2011
- EF3 tornado in Ontario
- killed 1 person, destroyed town
- RADAR on Lake huron gave 12 minute warning
Moore Tornado
May 20 2013
- EF4 in Oklahoma, Moore
- killed 24 people, gave 16 minutes in advance
Fog
- clouds on surface that reduce visibility to 1km
- nighttime when air temp. reaches dew point OR when warm air moves over cool lake
Blizzard
Requires:
1) wind of at least 40 km/hr
2) snow fall or blowing
3) visibility less than 1 km
4) wind chill less than -25
5) All conditions last 3 hours
Lake Effect SNow
- heavy snow falls on leeward side of lake
- cause by cold air moving over relatively warm water
Lake Effect Clouds
-this effect diminishes with freezing lakes
Sand Storms
- cause by downdrafton leading edge of thunderstorm
- rain evaporates before reaching surface
- occur in arid/semi-arid conditions
- called Haboobs in the middle east
Dust Devil
small spinning vortex of air over hot dry land
-caused by obstacles which cause the wind direction to change when hot air rises`
Ice Storms
-caused by rain freezing once reaching the surface
Drought
Extended period of unusually low precipitation
- ;inked to global weather patterns
- cause crop failure, famine, water shortage
Wind Chill
-correction factor that is caused by wind making it feel cooper then it is; thin layer of heated air above skin is taken away
Humidex
Correction factor to a temperature reading that makes air feel warmer than it is
Extratropical Cyclones
AKA mid-latitude cyclones
- form over land/water at latitudes 30-70 deg
- contain rain, snow, freezing rain
Tropical Cyclones
- form over warm water from latitudes 5-20 deg
- contain high winds, heavy rain, storm surges
Tropical Distrubance
large area of low pressure with unsettled weather
Tropical Depression
Unorganized area of thunderstorm
Tropical Storm
Unorganized area of storms withw inds 65-119 km/hr
Hurricane
Area with low pressure and winds of at least 120 km/hr
-AKA Tropical Cyclone/Typhoon
Eye
Region in center with light winds and clear/partly cloudy skies
Eyewall
ring of intense thunderstorms that whirl directly around eye
Spiral Rain bands
Rings of tall clouds/heavy rain that exist throughout hurricane
Storm Surge
- powerful winds that create abnormal rise in sea level
- most devastating effect of effects of hurricanes
Saffir Simpson Scale
-classify hurricanes [1-5] based on windspeed
Hurrican Juan
-category 2, near halifax
Hurricane Hazel
- 81 killed with flash floods
- No other disaster has killed as many in Canada
Minimizing Severe weather Hazards
- weather satelites find clouds, which show: mid-latitude cyclones and hurricanes
- RADAR detects intensity/type of precipitation
Weather Watch
Condition favour development of hazardous weather but none reported
Weather Warning
indicates the hazardous weather occuring in small area
Weather Advisory
Alerts public of less hazardous conditions
