Ch' 14 Climate

1
Ch. 14 - Climate

• Climatology the study of Earths climate and
  the factors that affect past, present, and future
  climatic changes.
• Climate is the long-term weather patterns of an
  area.
• Includes annual variations of temperature,
  precipitation, wind, other weather variables, and
  average weather conditions.
• An areas climate is compiled from meteorological
  records, which are continuously gathered at
  thousands of locations around the world.
• This includes daily high and low temperatures,
  amounts of rainfall, wind speed and direction,
  humidity, and air pressure.
• The data is averaged on a monthly or annual basis
  for a period of at least 30 years to determine
  the normals for a location.
• Normals are not intended to describe usual
  weather conditions. They are simply the average
  values over a long period of time.

2

• Climate Zones
• 1. Tropics the area between 23.5 south of the
  equator and 23.5 north of the equator.
• Receives the most solar radiation.
• 2. Temperate lies between 23.5 66.5 north
  and south of the equator.
• 3. Polar located from 66.5 north and south of
  the equator to the poles.

3
Climate Classification

• Koeppen classification system its based on
  average monthly values of temperature and
  precipitation.
• 1. Tropical Climates
• 2. Dry Climates
• 3. Mild Climates
• 4. Continental Climates
• 5. Polar Climates
• Fig. 14-4 (pg. 365)

4

• Microclimate a localized climate that differs
  from the main regional climate.
• Heat Islands the climates is warmer than in
  surrounding areas.
• Concrete buildings, asphalt, etc. reflects more
  solar radiation and causes urban areas to warm up
  more than rural areas.

5
Climatic Changes

• Ice Ages periods of extensive glacial coverage
  in which the average global temperatures
  decreased by 5 C.
• They alternate with warm periods of interglacial
  intervals (were in this now). The intervals are
  approximately 10,000 years.
• Short-term climatic changes are seasons.
• Why are do we have seasons?
• El Nino is another example of short-term climatic
  changes.
• Warm ocean currents develop off the western coast
  of South America.

6

• El Nino trends causes the jet stream to dip
  farther south, bringing violent storms to
  California and the Gulf Coast, which are usually
  south of the storm tracks.
• The effects of hot, moist upper air spread
  farther east, bringing stormy weather to areas
  that are normally dry and drought conditions
  areas that are normally wet.

7

• Maunder minimum a period of very low sunspot
  activity (11 year cycles).
• The low activity causes unusually cold climatic
  episodes called Little Ice Age.
• The Earths axis and orbit may trigger climatic
  changes.
• The Earths elliptical orbit appears to change,
  becoming more elliptical, then more circular,
  over the course of a 100,000 year cycle. Fig.
  14-14.
• The current tilt of the Earth is 23.5. The
  angle of the tilt varies from 22.1 to 24.5
  every 41, 000 years.
• Earths wobble occurs as it spins on its axis.
  This occurs over a period of about 26,000 years.

8
The Human Factor

• Greenhouse effect the retention of heat by the
  atmosphere due to certain greenhouse gases
  (carbon dioxide), that aids in this.
• Radiation travels in short wavelengths as it
  enters the atmosphere it loses a little energy.
  When it hits the Earths surface it loses more
  energy as it reflects back. The radiation is now
  in long waves with less energy the radiation
  cant escape the atmosphere. This causes the
  atmosphere to heat up some.
• Global warming the rise in global temperatures
  due to greenhouse gases trapping more solar
  radiation.
• The warmest years on record have occurred in the
  last 2 decades.
• This could cause melting of ice caps, flooding
  may occur because of this, deserts could spread,
  and more severe storms may arise.
• Scientists havent agreed on whats causing
  global warming.
• Most feel the evidence shows the large levels of
  carbon dioxide.
• Whats causing the increase? Can anything be
  done to stop it?

9

• Any process of burning fossil fuels gives rise to
  the increase in carbon dioxide levels.
• Mainly car exhaust.
• Some easy ways to conserve energy includes
  turning off appliances and lights when a room is
  not in use, turning down thermostats in the
  winter, and recycling.