Download Seasons, Weather, and Climate

Seasons, Weather,
and Climate
Unit 1: Basics of Geography
SEASONS
▪ Earth’s Tilt
▪ -Seasons affect the conditions in the atmosphere/create our
weather
▪ -Because of the earth’s revolution and tilt, different parts of the
earth receive the direct rays of the sun for more hours at certain
times in the year. Causes the changing seasons on earth.
▪ Tropic of Cancer and Tropic of Capricorn (latitude lines) mark the
points farthest north and south that the sun’s rays directly shine
over at noon. The day of which this occurs is called the solstice.
In the Northern Hemisphere, the summer solstice (beginning of
summer) is the longest day of the year. Winter solstice is the
shortest.
▪ - Twice a year, on the equinox, the days and nights all over the
world are equal in length. They mark the beginning of spring and
fall.
WEATHER
▪ Weather is the condition of the
atmosphere at a particular location and
time.
▪ Climate is the term for weather conditions
at a particular location over a period of
time.
WEATHER
▪ What causes the weather?
▪ Water vapor-Determines whether or not there
will be precipitation
▪ Cloud cover- clouds may hold water vapor
▪ Elevation- elevation above sea level increases,
air becomes thinner and loses its ability to hold
moisture
▪ Air movement- Winds move the air and
moisture it holds
WEATHER
▪
▪
Precipitation
-Depends on the amount of water vapor in the air. Warm air rises,
cools, and loses ability to hold water vapor; water vapor
condenses, droplets form in clouds. When amount of water is too
much for clouds to hold, precipitation falls.
▪ 3 classifications of water vapor
1. Convectional-occurs in hot, warm climates
2. Orographic- falls on the windward side of
mountains; block moist air and force it upwards; the
air cools
causing precipitation Land on the leeward
side is called
rain shadow because it gets little rain.
3. Frontal- More precipitation in the middle latitudes. A front is
a boundary between two air masses of different temps.
EXTREME WEATHER
▪ Hurricanes form over warm, tropical water.
Aka-typhoons (Asia) Air flowing over 80 degree + water
pick up huge amounts of moisture and heat energy.
Winds form an eye. Winds around the eye may be as
strong as 200 mph. Stretch over a vast area maybe
500 miles wide.
▪ Tornadoes- Form quickly; powerful funnel shaped
spiraling air. Born from strong thunderstorms. Winds
swirl counterclockwise around a low pressure center.
Can reach up to 300 mph. Generally travel small
distances. However, can be a mile wide and stay on
the ground for hours.
EXTREME WEATHER
▪ Blizzards- Heavy snowstorm with winds
more than 35 mph.
▪ Droughts- Long period of time without
rain or with very little rainfall.
▪ Floods- Water spreads over land not
normally covered with water.
CLIMATE
▪
▪
▪
▪
▪
4 factors influence the climate of a region
1. Wind and ocean currents
2. Latitude
3. Elevation
4. Topography
CLIMATE
▪ Wind currents▪ Wind and ocean currents help distribute the
sun’s heat from one part of the world to another
through convection- transfer of heat by an
upward motion of air.
▪ Wind is caused by air expanding b/c of heat;
low air pressure created; cooler dense air in a
nearby high pressure zone rushes into the lowpressure area
CLIMATE
▪ Ocean currents- like rivers flowing in the ocean
▪ Warm waters flow away from the equator; cold
water towards the equator.
▪ Zones of latitude- Geographers divide the earth
into 3.
1. Low or tropical
2.Middle or temperate
3. High or polar
CLIMATE
▪
▪
▪
▪
Tropical zones are on either side of the
equator- hot all year long.
Temperate zones lie at the middle latitudes;
climates vary from relatively hot to relatively
cold
High zones encircle the North and South
poles; cold all year long.
Elevation- landforms affect the climate alsomountain areas
CLIMATE
▪ El Nino- the warming of waters off the
west coast of S. America. This is a
natural change in climate. Happens every
2-7 years. Easterly winds in Pacific
change direction or slow- ocean temp
changes. It affects the weather
worldwide. Heavy rains towards the
Americas. Australia and Asia experience
drought conditions.
CLIMATE
▪ La Nina- Reverse of El Nino. Winds blow
warmer water on the lands of the Pacific
rim
▪ Increase in precipitation in India, dryness
along the Pacific coast of the Americas
CLIMATE
▪ Global warming- Air temps are increasing
▪ Some believe- natural warming of cooling
cycles
▪ Others believe caused by the greenhouse
effect- the layer of gases released by burning
coal and petroleum traps some solar energy
causing higher temps in the same way a green
house traps solar energy
▪ Predict if it continues- ice caps will melt,
flooding, covering of islands, changing global
climate.
Climate Regions, Soil,
Vegetation
Unit 1: Basics of Geography
World Climate Regions
□ Geographers must make generalizations
what the typical weather conditions are
over many years in a location. They look at
precipitation and temperature
-Tropical
-Dry
-Mid latitude
-High latitude
-Highland
World Climate Regions
These 5 are divided into small subregions
□ Tropical wet- Always hot- avg. temp of 80
degrees; rains daily;more than 80” of
rain/yr; Central and South America, Africa,
SW Asia
□ Tropical wet and dry- Rainy and warm in
summer; dry and cool in winter; Africa,
South and Central America, parts of Asia
World Climate Regions
□
□
Semiarid- Receives about 16” of
rain/yr;hot summers, mild to cold
winters, some snow; interior of
continents or around deserts; good
agricultural land
Desert- Can be hot or cool/cold;
receive less than 10” of rain/yr.
World Climate Regions
□
□
Mediterranean- Around Mediterranean
Sea;west coast of the U.S. and parts of
Australia;summers- dry and hot;winterscool and rainy;rich agricultural activity
Marine west coast- Close to the
ocean;cloudy, foggy, and damp;west coast
of the U.S. and Canada and most of W.
Europe;precip evenly distributed thru the
year;smog in industrial regions
World Climate Regions
□
□
Humid Subtropical- Summer heat and
humidity; E. coast of
continents;subject to hurricanes in
late summer and fall; S.E. part of U.S.
and large areas of China; wintersmild to cool;grow rice
Humid Continental- Great variety in
temp/precip;mid latitude interiors of
North Hemisphere
continent;experience 4 seasons
World Climate Regions
□
□
Sub arctic- Taiga (evergreen
forests);Canada/Russia; summers- short and
cool; winters- very cold;temps at freezing or
below 5-8 mos/yr
Tundra- Flat, treeless ring around the Arctic
Ocean- tundra;almost all located in the
North Hemisphere;less than 15” of
rain/yr;permafrost- subsoil is constantly
frozen; summer lasts for a few weeks- temp
slightly above 40 degrees
World Climate Regions
□
□
Icecap- Snow, ice, permanent
freezing temps;Polar deserts- Less
than 10” of rain/yr
Highlands- Climate varies with
latitude, elevation
Soil
□ Worlds food supply depends greatly on top
6” of soil
□ Soil characteristics and climate- major
influences in vegetation regions: depth,
texture, and humus content determine
vegetation
□ Soil, temp, and moisture determine the
type of vegetation in a region
□ Ecosystem- interdependent community of
plants and animals
Vegetation
□ Biome- ecosystem of a region
-Forest
-Grassland
-Desert
-Tundra
□ Forestlands- Categorized by their treesbroadleaf or needleleaf
-Broadleaf- deciduous- oak, maple, and
cottonwood- rainforest covered with these
mostly in No. Hemisphere
Vegetation
□ Needleleaf-coniferous- pine, fir,
cedar- cone bearing- No. regions of
North America, Asia, and Europe
□ Grasslands- Flat regions and few
trees
□ Tundra- Mosses and lichens
□ Desert-cacti, sagebrush, shrubs
Human-Environment
Interaction
□ Human activities on soil and
vegetation is immense
■ Building dams, irrigation systems,
planting crops, slash and burn