earth science chapter 14 climate

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Transcript earth science chapter 14 climate

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LIMATE

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HAT IS

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LIMATE

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 Climatology - study of earth’s surface climate and the factors that affect the past, present and future climate changes.

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LIMATE DESCRIBES

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VERAGE

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RECIPITATION

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ATTERNS

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RECIPITATION

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ATTERNS

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ORMALS  Data is collected at 1000’s of locations is compiled for over 30 years to establish Normals or standard values   Must be used with caution Why?

   1) Weather conditions may differ from Normals 2) Normals not intended to describe usual weather condition 3) Normals only apply to specific areas

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HAT CAUSES

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LIMATE

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HREE MAIN FACTORS

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ATITUDES  Amount of solar radiation varies place to place. Why? Earth is tilted on its axis and it affects how the sun’s rays strike the earth   23.5 S to 23.5 N - Tropics - receives the most sun . Temperature warm year round    23.5 N- 66.5 N 23.5 S- 66.5 S Temperate Zone - Temperature Moderate

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EMPERATE

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23.5 N – 66.5 N

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23.5 S – 66.5 N

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ATITUDES CONT

……. 66.5 N

AND POLAR

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ONE

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UN STRIKES AT LOW ANGLES

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OLD TEMPERATURES

. 66.5 S -

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OPOGRAPHY

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FFECTS   H 2 O heats up and cools down more slowly than land. Coastal regions are warmer in winter and cooler in the summer than inland areas of similar latitudes. Temperature in lower atmosphere decreases with altitude.  Orographic lifting - air rises over mountain, rising air cools and condenses then drops moisture.

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OPOGRAPHY

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FFECT

 Air Masses  2 courses of weather movement interactions of air masses - air masses affect climate tool  

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IR MASSES OF

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MERICA

 Region and Origin  Caused by difference in the amount of solar radiation. Average weather conditions in or near air masses are fairly similar to conditions. Exhibited by air masses.

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S UN R AYS H ITTING THE EARTH

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AYS IN RELATIONSHIP TO

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ATITUDE

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LIMATE

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LASSIFICATION  How are climates classified?

    Based on the climate and precipitation and vegetation Continental Polar High elevations 

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ORLD

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LIMATES

 Tropical Climate - 600 cm of rainfall  Heat + rain = rainforest under the influence of maritime tropical air   Transition zones border the rainy tropics    Tropical wet distinct African Savannas Tropical dry dry season  

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LIMATES  Dry Climates - cover 30 % or earth - largest climate zone - where most of the deserts are located: Sahara, Gobies, Australian         Continental Tropical dominates -low precipitation -vegetation scarce -intense solar radiation -high rate of evaporation - few clouds -2 subtypes: arid region (deserts) Semi and steppes 

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LIMATES  3 subtypes  - Humid subtropical climate - influenced by subtropical high pressure systems over oceans Southeast of the U.S.

  -Marine west coast - dominated by the constant inland flow of air from ocean- mild winters and cool summers  -Mediterranean - Italy, Spain - summers warm lack of cool ocean currents in the Mediterranean Sea

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OLAR

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LIMATES        Coldest regions on earth mean temperature of warmest month is lest than 10°C precipitation is low cold air does not hold cold moisture. Amount of heat radiates from earth is low thus there are no convection currents necessary to release precipitation. Variations - high elevations, includes parts of Andes Mountains of South America

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ICRO

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LIMATE

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LOCALIZED CLIMATE WITHIN A MAIN REGIONAL ONE

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ICROCLIMATE

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EAT

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SLANDS

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CLIMATE IS WARMER THAN THE SURROUNDING RURAL AREAS

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climate is warmer than the surrounding rural areas.

 Ice Ages - Earth surface was totally covered by vast sheets of ice. Average global temperature decreased by 5°C sparked the advancement of ice sheets. Interglacial Intervals = alternating of cold/warm periods.

  We are now in a interglacial period. Glaciers covered from east to west and as far south as Indiana.

  Retreat - scoured the Finger Lakes of New York / Great Lakes - Michigan 

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ORTH

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MERICA

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GE COVERAGE

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GE COVERAGE OF THE WORLD

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UROPE

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OVERAGE

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EASONS  Seasons - short term climate changes caused by regular variations in daylight, temperature and weather patterns. Summer - North Pole titled toward sun - Northern Hemisphere / Southern Hemisphere - winter

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HY DO WE

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AVE

SEASONS?

DEGREE OF INCOMING SOLAR ENERGY

SEASONS IN THE LATITUDES

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INO

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ONT

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 Warm currents that occasionally develops off the western coast of South America normally.

 No reason - Trade winds weaken - allows warm winters from the Western Pacific surge eastward towards the South American coast   Convection currents strengthen - Northwest coast of South America becomes warm and wetter.

  Jet Stream moves south. Weather system take a southern track - storms in California and Gulf Coast

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INO

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INO

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ONT

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 + positive effect - strong upper winds keep the tropical disturbances down  Change can be Natural Past climate changes found studying tree rings, ice core samples, fossils and radioactive carbon.

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HARACTERIZED BY UNUSUALLY COLD OCEAN TEMPERATURES IN THE

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QUATORIAL

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ACIFIC  a. La Niña often causes drought conditions in the western Pacific ; flooding in northern South America; mild wet summers in northern North America, and drought in the southeastern United States.

Weak 1953 1958 1963 1969 1976 1977 2004 2006 El Niño Mod 1951 1968 1986 1987 1994 2002 2009 Strong 1957 1965 1972 1982 1991 1997 Weak 1950 1954 1956 1964 1971 1974 1983 1984 1995 2000 2005 2011 La Niña Mod 1970 1998 2007 Strong 1955 1973 1975 1988 1999 2010 47

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 Changes in the earth’s climate is caused by:     1) Solar activity 2) Changes in the earth’s tilt 3) Earth’s orbit 4) Volcanic eruptions

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CTIVITY

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UNSPOTS      Low sunspot activity - Maunder Minimum (“Little Ice Age”) cold dramatic conditions.

High sunspot activity - Temperatures are warmer - Earth’s orbit - shape of the earth’s elliptical orbit changes and becomes more elliptical than circular. If the orbit elongates the earth is closer to the sun. Temperature is cooler. The earth’s tilt is 25.3° and it tends to vary from 22.1° to 24.5° every 41,000 years. Changes in the tilt causes seasons to be more severe - winters-warmer, summers cooler. Colder weather causes ice sheets to expand causes ice age

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POTS

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ARTH

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OBBLE  Earth wobbles as it spins - axis point towards North Star “Polaris”. When earth wobbles, axis tilts towards star “Vega” when winter extends.

 The Northern Hemisphere is the farthest from the sun while the Southern Hemisphere is the closest and enjoying summer.

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OLCANIC

ACTIVITY

 Tiggers climatic change    Dust suspended in the atmosphere for several years blocking out the incoming solar radiation.

Lowering global temperatures High active periods of volcanos, the planet tends to have cooler temperatures

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UMAN

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ACTOR TO

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LIMATE

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HANGE       Greenhouse Effect Retention of heat by the atmosphere by the accumulation atmospheric gases called Greenhouse gases water vapor , carbon dioxide , methane , nitrous oxide , and ozone . Greenhouse gases greatly affect the temperature of the Earth ; without them, Earth's surface would average about 33°C colder than the present average of 14 °C (57 °F).

[ Since the beginning of the Industrial Revolution , the burning of fossil fuels the concentration of carbon cycle .

has contributed to a 40% increase in carbon dioxide in the atmosphere from 280 ppm to 397 ppm, despite the uptake of a large portion of the emissions by various natural "sinks" involved in the Anthropogenic carbon dioxide (CO 2 ) emissions (i.e., combustion of carbon based fuels , principally wood , coal , oil , and natural gas .

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LOBAL WARMING