Transcript Ch-4 - A Virtual Field Trip of Physical Geography in Ventura County

Energy = the ability to
do work; anything that
changes the state or
condition of matter.
The sun, a large
thermonuclear reactor,
supplies the energy
that supports life on
earth and energizes
most atmospheric
processes.
This energy is derived
through the process of
fusion.
Temperature
= a description of the average kinetic energy,
or energy of movement, of the molecules
in a substance
Temperature scales:
Fahrenheit, Celsius, Kelvin
Heat (thermal energy) is transferred from
one object to another because of
differences in temperature.
Insolation
radiation
Incoming
solar
Energy from the sun is radiated
out in the form of
electromagnetic waves which
travel at the speed of light.
EM waves are classified
according to their wavelength.
Electromagnetic Spectrum
Terrestrial Radiation
Solar Radiation
Shortwave vs. Longwave
This energy can move from place to place by:
Radiation – flow of energy emitted from an object
•Conduction – movement of energy from molecule to
molecule
•Convection – energy transferred vertically by a
moving substance
•Advection – energy transferred horizontally by a
moving substance
And once there, it can be:
Absorbed
Reflected
Scattered
Transmitted
Albedo: the reflectivity of an object
Albedo on Earth
Heating and Cooling Processes
Adiabatic cooling
• rising air
• expansion
Adiabatic warming
• descending air
• compression
No loss or gain of heat with either
Latent heat: the storage or release of energy through
phase changes in the physical state of matter
Loss or gain of heat
Earth’s Energy Budget: a long-term balance
Heating of the Atmosphere video
Variations in temperature/heating are
controlled by…
Latitudinal Differences
•angle of incidence
Where is the angle of incidence the largest and the smallest?
Variations in temperature/heating are
controlled by…
Seasonal Differences
Different locations have
different:
•day lengths
Where on Earth does daylight and darkness occur in equal lengths of time
always (12 hours each)?
Where on Earth does daylight and darkness occur in unequal lengths of time
(24 hours only)?
Spatial variations in heating:
…is further controlled by how
much atmosphere the solar
radiation has to travel through as
well as atmospheric obstruction.
Energy Budget & Latitude:
Diagram
•gases
•particulates
•clouds
Where is the longest path found that solar radiation must take?
Characteristics of Land and Water:
differences in heating
Heating - land surfaces heat up more rapidly than water.
Cooling – land surfaces cool off more rapidly than water.
Implications - Continental land surfaces (inland) have a higher range in daily
temperatures, Maritime coastal surfaces (along the ocean) have a lower range
in daily temperatures.
Land and Water contrasts:
Annual Temperature Curves
Continental vs maritime climates
Spatial variations in heating
Latitudinal Radiation Balance - the surplus radiation
that results in the tropics is balanced by the deficit
that occurs in the polar regions.
This imbalance is addressed by…
Heat Transfer Mechanisms:
Atmospheric and Oceanic Circulation
Global
Temperature
Patterns
Changes with latitude
and season
Global Average Annual
Temperature Variations
Summary of
Global Temperature Controls
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Altitude/Elevation
Latitude (0-90N/S)
Seasons
Land-Water Contrasts
Oceanic Currents
Sensible temperature - what we feel the air
temperature to be, taking into account all factors like
amount of moisture present, the wind (if present), etc.
Vertical Temperature Patterns
Environmental lapse rates – the
observed trends of vertical temperature
changes in the atmosphere
Temperature Inversions:
Surface
•Radiational inversions – most common type of
inversion layer seen at ground level, caused by
rapid cooling at the surface during the night time
with warmer air aloft
•Advectional inversions – during a horizontal
inflow of cold air into an area, commonly
produced by cool maritime air moving inland that
displaces warm air masses
•Cold-air drainage inversions – during winter in
some mid-latitude regions, cold air slides down a
slope into a valley displacing warmer air
Upper-Air
•Subsidence inversions – a deep/aloft inversion,
the result of sinking air associated with highpressure conditions
Vertical Temperature Patterns
Radiational
surface
inversion
Example: Los Angeles
major vs. minor
smog days
Urban Heat Islands: Cities
Global Warming and
the Greenhouse Effect
Global Warming video
http://www.msnbc.com/news/106332.asp?cp1=1
Human-induced atmospheric changes
CO2
Human-Enhanced Global Warming
Kyoto???
INTERNATIONAL DEBATE
1992 Rio de Janeiro – established panel of scientists to study climate
change… Intergovernmental Panel on Climate Change (IPCC).
1997 Kyoto Protocol – 167 countries agreed to reduce carbon emissions to
1990 levels (Europe 8%, Japan 6%, USA 7%). (President Clinton)
1998 Buenos Aires – USA threatened not to make cuts unless developing
countries (ex. India and China) also make cuts.
2000 The Hague – stand off between Europe and USA re: methods. USA
wants to meet ½ target by using carbon sinks and trading.
2001 Marakesh – USA did not attend climate meeting. (President Bush)
2005 Russia ratified the Kyoto agreement, USA’s federal government did
not; ignoring global warming and the greenhouse effect.
2009 Copenhagen Climate Meeting, Denmark – USA and China worked
together; possible 2010 treaty to reduce anthropogenic greenhouse gases at
home and abroad. Clean energy, accountability/transparency, key to
controlling global warming. (President Obama)
The problem:
• Rate of change
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Intergovernmental Panel on Climate Change (IPCC)
Warming at unprecedented rates
Increase in temperature vs. time
Cause is predominantly anthropogenic = HUMANS
• Increased global average temperatures
– 1 degree F every century?
– Predicting even more change (up to 7 degrees this century)!
• Expected changes for Earth
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Melting of polar ice
Increase in sea level
Shifts in climate everywhere
Extreme weather phenomena
Species/Community extinctions
• Can we survive it?
– Can we change? ADAPT
More Global
Warming
Impacts…
Ice
Melting at the
Poles!
Oceans are
Warming, along
with
Atmosphere.
Hurricane Dean became a low pressure
system affecting the south-western USA
in August 2007…is our local semi-arid
climate becoming more tropical?
Homework
1. Read Chapter 4
2. ARTICLE (handout in class).
3. Write a summary about your opinion
on global warming and use your own
observations and available research
to back up your statements.
•
5 HWs total due before the midterm.