Earth-Sun Relationships

Weather and Climate Weather is a the condition of the atmosphere in one place during a limited period of time Climate is the term for the weather patterns that an area typically experiences over a long period of time

What determines climate? Climate is determined by many things, but most importantly it is determined by the Earth’s position in relation to the sun

The Earth’s Axis The Earth spins on it’s axis The axis is an imaginary line running from the North to the South pole through the planet’s center The axis is at an angle of about 23.5 degrees

Temperature The angle of the axis affects the temperature Temperature is the measure of how hot or cold a place is The temperature is measured either in Fahrenheit or Celsius

Rotation and Revolution The Earth spins on it’s axis and makes one complete rotation every 24 hours Earth rotates from east to west The Earth also revolves around the sun It takes 365 days for the Earth to make one complete revolution around the sun The Earth’s tilt and it’s revolution cause changes in seasons

The Greenhouse Effect The greenhouse effect is when the Earth’s atmosphere traps some of the suns radiation Most of the sun’s radiation is reflected back into space, however enough seeps through to warm the land, water, and air

Global Warming The rise in recent decades of the Earth’s temperatures is believed to be caused by global warming which is believed to be caused in part by human activities Some scientists, however, believe that global warming is a natural cycle, not caused by humans Global warming is when there is a rise in the amount of Carbon Dioxide (CO2)in the atmosphere because of the burning of fossil fuels (coal, natural gas, and oil) CO-2 absorbs more heat reflected by the Earth, trapping it in the Earth’s atmosphere

The Latitude Zones Because of the rotation and tilt of the Earth, the sun hits the Earth’s latitudes for certain periods of time The Low latitudes are between the Tropics of Cancer and Capricorn (23 ½ degrees north and south latitude) The low latitudes receive the direct rays of the sun year-round The low latitudes have warm, hot climates

High Latitudes The high latitudes are at the Earth’s polar areas When either the Northern or Southern Hemisphere is tilted toward the sun, the pole receives continuous sunlight (causes the “midnight” sun)

The Mid-latitudes The mid-latitudes have the most variable weather The mid-latitudes are found between the Tropics of Cancer and Capricorn and the Arctic and Antarctic circles The mid-latitudes experience dramatic seasonal weather changes In the summer they receive the warm air from the tropics and in the winter, the cool air from the poles

Elevation Elevation also plays a role in climate The Earth’s atmosphere thins as altitude increases and thinner air retains less heat

Wind and Water The wind and water also impact the Earth’s climate Wind – air moving across the Earth’s surface Wind occurs because the sun heats up the Earth’s atmosphere unevenly cause high pressure and low pressure The wind helps to distribute the sun’s heat around the planet

The impact of water Mountain ranges can cause heavy precipitation on the windward side, and almost no precipitation on the leeward side As a result, the climate on one side of a mountain is cool and wet, and the other side is warm and dry

Climate Regions

Different Regions Geographers divide the Earth into several different climate regions: Tropical Dry Mid-latitude High latitude Highlands ***Each of these regions are further divided into smaller ones

The smaller regions The smaller regions are characterized by the natural vegetation Natural vegetation is the plant life that grows in an area where the natural environment is unchanged by human activity

Tropical Climates Tropical climates are found in or near the low latitudes The most widespread kinds of tropical climate regions are tropical rain forests and tropical savannas Lush vegetation is common in tropical climates and wildlife is also abundant Rain occurs almost daily in tropical rain forests In tropical savannas there are dry winters and wet summers with high temperatures year-round

Dry Climates There are two types of dry climates: Desert climates Steppe climates

Deserts are dry areas with sparse plant life Rainfall in deserts rarely exceed 10 inches Desert vegetation consists of scattered shrubs and cactus In some areas there may be an oasis, which is an area of lush vegetation A steppe climate is a large, treeless grassland that typically borders a desert Annual precipitation is usually between 10 and 20 inches

Mid-latitude Climates Mid-latitudes include four temperate regions: Marine West Coast Mediterranean Humid Sub-tropical Humid Continental

Marine West Coast Includes: Pacific Coast of North America, most of Europe, and parts of S.A., Africa, Australia, and New Zealand Ocean winds bring cool summers and damp winters Natural vegetation includes coniferous and deciduous trees Coniferous – have cones Deciduous – have broad leaves, change colors, and drop their leaves in autumn Most marine west coast climates have mixed forests

Mediterranean This includes land surrounding the Mediterranean Sea, some areas of California, and parts of southern Australia Have rainy, mild winters and hot, sunny summers Natural vegetation includes chaparral, thickets of woody bushes and short trees

Humid Sub-tropical Southeast U.S., and southeast parts of South America and Asia Brings short, mild winters, and nearly year-round rain Humidity levels are high in these areas because of the wind patterns and high pressure related to nearby oceans Natural vegetation consists mostly of prairies, or inland grasslands, and forests of deciduous trees

Humid Continental Southern Canada, Western Russia, and northeastern China Landforms influence this type of climate region Vegetation is similar to that found in Marine West Coast As you travel further north, the winters are more severe and summers are shorter

High Latitude Climates High latitude climates include subarctic and tundra climate regions Freezing temperatures are common Vegetation is limited Subarctic climate region is just below the Arctic Circle – winters are bitterly cold and summers are short and cool Only a thin layer of soil thaws each year – below it is permafrost – permanently frozen subsoil Can support some needled evergreens

Tundra Climate Also a high latitude climate, tundra climate regions are very cold Winter darkness and bitter cold last for half the year, and the constant light in the summer but little heat Vegetation is limited to low bushes, very short grasses, mosses, and lichens

Highlands Climate Elevation can also determine a climate region, regardless of latitude What characterizes highlands climate is the thinning of the altitude Natural vegetation varies because of the changes of temperature as one goes up the mountain