Transcript The Atmosphere (Abridged)

The Atmosphere-history
• 3.2 billion years ago (bya) atmosphere mostly
__________ and ________ (Life begins in sea)
• 2.3-2.7 bya photosynthetic bacteria
(cyanobacteria) began producing __________
• 400-500 mya ______________ levels in
stratosphere sufficient to protect land plants
from UV radiation.
The Atmosphere-current
composition
•
•
•
•
•
_______ % N2
21 % _______
Around 1% Ar2
0.01-4% _______
0.037 CO2
The Atmosphere-current composition
• The __________________________________
- Natural warming effect of the troposphere
1. sunlight hits the Earth’s surface turning
into infrared (heat) radiation
2. heat risessome escapes into space
some heats greenhouse gases
emitting infrared radiation
which warm the troposphere
+
The Atmosphere-current composition
• Major greenhouse gases:
- ________________________________
(primary)
- CO2
- O3 (ozone)
- _______________________ (methane)
- N2O (nitrous oxide)
- CFCs (chlorofluorocarbons)
The Atmosphere-current composition
• Mean global temperature
14.53oC or 58.14oF (2000-2008)
14.0oC or 57.2oF (1951-1980)
(Source http://data.giss.nasa.gov)
-18oC
or 0oF without greenhouse effect
The Atmosphere-Climate
• Climate: ____________________ patterns of
atmospheric conditions
-mainly influenced by average _____________
and __________________________________
-globally follows a cyclic pattern
+ glacial periods lasting around _________ yrs
+ interglacial periods lasting around
________________________ yrs
+ Holocene epoch—nearing end of
interglacial period
The Atmosphere-climate
Factors that affect global climate
 __________ of the Earth’s orbit (eccentricity)
 ___________ of the Earth’s axis (precession)
 changes in the _________ of the Earth’s axis
(obliquity)
 volcanic activity
 changes in _____________________ output
 atmospheric composition
The Atmosphere-climate
Factors that affect regional climate
 uneven ____________ of the Earth’s surface
(varies by ________________ and season)
 ______________ of the Earth
 ocean currents
 mountains
 altitude
 _____________________ of the Earth
The Atmosphere-factors that affect
regional climate
Uneven heating of the Earth’s surface
 Consistent, year-round heating at equator
 More seasonal variation as latitude increases
 Uneven heating produces atmospheric areas
of low pressure (less dense, rising air) and
high pressure (more dense, falling air.)
 Pattern alternates about every 30 degree
change in latitude (p. 125)
The Atmosphere-factors that affect
regional climate: Earth’s rotation
Coriolis Effect—The apparent deflection of a
moving object due to the motion of the Earth
underneath it
The Atmosphere-factors that affect
regional climate: ocean currents
• Water’s high ___________________________
causes it to gain and lose heat slower than
land masses
• Oceans produce _________________ climates
• Changes in _________due to temperature and
salinity differences and the Earth’s _________
produce ocean circulation patterns
• Europe is warmer than it should be due to
warm ________________________________
The Atmosphere-factors that affect
regional climate: ocean currents
The Atmosphere-factors that affect
regional climate: mountains
• Mountains force air masses to __________ as
they pass across them
• Rising air _________ and moisture condenses
producing precipitation on the “windward’
side
• Descending air on the “leeward” side has ____
moisture producing areas of lower
precipitation
• Called the “Rain shadow effect”
The Atmosphere-factors that affect
regional climate: mountains
The Atmosphere-factors that affect
regional climate: altitude
Average temperature decreases about ___oF for
every _________________ feet in altitude
Barrons p. 117
The Atmosphere-factors that affect
regional climate: tilt of the Earth
• The _________________________!
The Atmosphere-weather
• Weather-The short-term conditions in the
troposphere at a location.
• Includes atmospheric conditions such as
- ______________________________
- ______________________________
- ______________________________
- ______________________________
- ______________________________
- ______________________________
The Atmosphere-weather:
temperature
• Measure of _____________________ energy
• Differences produced by ___________ heating
of Earth’s surface
• Maps of areas with the same temperatures
are called _____________________________
The Atmosphere-weather:
temperature
The Atmosphere-weather: temperature
• Normally troposphere gets _______________
with altitude
• Temperature _______________________--a
layer or warmer air above cooler surface air
The Atmosphere-weather: temperature
The Atmosphere-weather: temperature
• _________________ Front—leading edge of
advancing mass of cold air
-more dense so slides __________ warmer air
lifting it
-rising warm air produces thunderheads and
rainstorms
The Atmosphere-weather: temperatureCold Front
The Atmosphere-weather: temperature
• __________________ Front—leading edge of
advancing mass of warm air
-__________ dense so rises up over colder air
-more gradual lifting produces thickening
clouds and longer periods of rain
The Atmosphere-weather: temperatureWarm Front
The Atmosphere-weather: temperature
(note symbols)
The Atmosphere-weather:
clouds
• ______________________________ of water
vapor in rising air due to lower temperatures.
• ____________________ conditions determine
cloud type
• Cloud names indicate _________________
and ______________________________
The Atmosphere-weather:
Clouds
Cirrus Clouds:
-_______ altitude
-Thin and wispy
The Atmosphere-weather:
Clouds
Stratus Clouds
-_____________
altitude
-layered and
sheetlike
The Atmosphere-weather:
Clouds
Cumulus Clouds
-Low to medium
altitude
-______ bottom and
fair weather
-Cumulonimbus are
_____________
clouds
The Atmosphere-weather:
Pressure
 Earth’s _________ pulling down on molecules
in the atmosphere creates atmospheric
pressure
Atmospheric pressure at sea level is:
- 760 mm of Hg
- 29.9 in. of Hg
- 14.7 psi
- 1013.25 millibar
The Atmosphere-weather:
Pressure
• Maps of areas with the same barometric
pressure are called ____________________
• Areas of _______ pressure bring cloudy rainy
weather. Counterclockwise (NH) (cyclone)
• Areas of ______pressure usually indicate clear
weather. Clockwise (NH) (anticyclone)
• Air moves from areas of ______ pressure into
areas of _____________ pressure—wind!
The Atmosphere-weather:
Pressure
The Atmosphere-weather:
Jet Stream
• Narrow, fast-moving wind current in the upper
___________________________________
• Position usually coincides in part with the
regions of greatest ____________________ in
the lower troposphere
• Also called ____________ jet stream, because
of the importance in moving cold, polar air.
The Atmosphere-weather:
Jet Stream
Atmospheric-Oceanic Interactions: El NinoSouthern Oscillation (ENSO)
• Normal conditions in eastern equatorial
Pacific Ocean
Atmospheric-Oceanic Interactions: ENSO
Atmospheric-Oceanic Interactions: ENSO
• El Nino-A ___________ of the surface water of
the eastern and central Pacific Ocean,
occurring every 4 to 12 years and causing
unusual global weather patterns.
• trade winds that usually push warm surface
water ______________ weaken, allowing the
warm water to pool as far eastward as the
western coast of South America.
Atmospheric-Oceanic Interactions: ENSO
Atmospheric-Oceanic Interactions: ENSO
Atmospheric-Oceanic Interactions:
La Nina
• _______________ of the surface water of the
eastern and central Pacific Ocean, causing
similar, generally opposite disruptions to
global weather patterns.
• Trade winds blow more strongly than usual,
pushing the sun-warmed surface water farther
west and increasing the upwelling of cold
water in the eastern regions.
Atmospheric-Oceanic Interactions: El Nino vs. La Nina
Typical vs. El Nino vs. La Nina
• Typical
• Winds off the western coast of equatorial South America blow
_______________________, pushing surface waters west.
• Cooler deeper waters _______(upwelling) to replace moving
surface water, bringing nutrients to the surface, increasing fish
populations.
• El Nino
• Winds off the western coast of equatorial South America
lessen, stop or start to blow _________________________.
• Warmer surface waters deepen as they “run into” western
South America. Deep nutrients do not rise, ______________
fish populations.
• La Nina
• Winds off the western coast of equatorial South America
strengthen, blowing east to west, pushing surface waters
__________.
• Surface waters off of the west coast of equatorial South
America _________________ due to increased upwelling.
Increased fish populations.
Typical vs. El Nino vs. La Nina
• Typical
• Normal _____________________ in western South America,
southeastern Asia, eastern Africa, southeastern South
America and southeastern U.S.
• Normal rainfall in southern Africa, Australia, eastern South
America, northwestern and northeastern Canada and U.S.
• El Nino
• ___________ rainfall in western South America,
southeastern Asia, eastern Africa, southeastern South
America and southeastern U.S.
• Less rainfall/_________________ in southern Africa,
Australia, eastern South America, northwestern and
northeastern Canada and U.S.
• La Nina
• Decreased rainfall in western South America, southeastern
Asia, eastern Africa, southeastern South America and
southeastern U.S. Increased ________________ in the U.S.
• More rainfall in southern Africa, Australia, eastern South
America, northwestern and northeastern ________________.
Typical vs. El Nino vs. La Nina
• Typical
• Normal number of Atlantic and Pacific ______________
• _________________ temperatures in eastern Asia,
northwestern Canada and U.S. and northeastern
Canada and U.S.
• El Nino
• _____________ Atlantic and more Pacific hurricanes
• ____________________ temperatures in eastern Asia,
northwestern Canada and U.S. and northeastern
Canada and U.S.
• La Nina
• “Sometimes” _____________ Atlantic and fewer Pacific
hurricanes
• Cooler ___________ temperatures in southeastern and
southwestern U.S.
• ____________ winter temperatures in north central
U.S.
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