Climate and Biomes in North America

1) Global and North American
geographic patterns of climate



3) Climate Diagrams
2) Biomes


Geographic patterns of temperature and
precipitation
Biomes are defined by climate
3) Climate and Biomes of North America



Desert
Temperate Forest
Grassland
Global Pattern of Climate: Temperature



Temperature varies across the globe – why?
One reason, because the sun heats the earth surface
unevenly.
The intensity of solar radiation varies with the incidence
angle of the sun
Sun’s energy is the source
of warmth on earth
 Earth rotates on an axis
defined by north and south
pole
 Sun’s rays are received
with greater intensity near
the equator and less
intensity near the poles

Global Pattern of Climate: Temperature

Global temperature
•Equator – hot temperatures
•As move North – cooler - North Pole – cold
•As move South – cooler – South Pole – cold
January 15,
2005
Global
Temperatures
Satellite
North American Pattern of Climate:
Temperature
Average
North American temperature
• Temperatures in North America follow the general
pattern of being warmer in the south and
increasingly cooler as you move north.
Example:
Average January
Temperature in
degrees Farenheit
Global Pattern of Climate: Precipitation



Precipitation varies across the globe – why?
One reason, is the global circulation pattern of air
The energy from the sun is still the basic driver – but the
global pattern of ppt is more complicated than temperature
At the equator air heats it
rises (like hot air balloons),
then it cools, and this forms
rain
 Air circulates in a general
pattern of rising air that
brings rain and descending
air that is very dry
 These large global
patterns form ‘bands’ of
wet and dry areas

Global Pattern of Climate: Precipitation


Average Global Precipitation
Wet band near equator, dry band 30 degrees S and N
latitude (where the earths deserts occur), then another
wet band 60 degrees S and N latitude (where earth’s
temperate forests occur).
North American Pattern of Climate:
Precipitation
Average
North American precipitation
• Finding a general pattern of precipitation is more
complicated than temperature. But!! Can you see a pattern in
this map?
Example:
Average PPT
Greener is wetter
Oranger is drier
North American Pattern of Climate:
Precipitation
Average
North American precipitation
• Although many factors effect the amount of precipitation an
area receives, one important factor in the US is the location of
mountain ranges.
Above is an average annual PPT
map. See how mountains effect
pattern of rainfall?
Climate Diagrams

Climate Diagrams are a very useful way
to understand the climate of a place
• A graph of climate for a
specific place
• Shows both temperature and
precipitation on the same
graph
• It is the long term average of
T and PPT
• Its monthly – so you see the
seasonal pattern
Climate – Climate Diagram
Temperature
F 104°
Precipitation
3.15” In.
68°
1.57”
32°
0”
0°
Climate and Biomes (Ecosystems)

Biome Definition




Biomes are areas on earth that are classified by
their climate and their most common types of
plants.
Example – the ‘desert biome’ or the ‘tropical
rainforest biome’ or the ‘grassland biome’.
Even though the definition uses climate and
plants, animals also are included in a type of
biome
Important: CLIMATE is how we define a
biome, and climate influences the
distribution of biomes on the earth.
Climate and Biomes (Ecosystems)

A few Biomes of North America




Desert
Temperate Forest
Temperate Rainforest
Grasslands
Biomes – Desert Biome

Desert Biome: Characteristics
Climate characterized by 1) low amounts of rain,
2) drought!!!, 3) high temperatures in summer,
4) but – some deserts can be cold in winter.
Desert
Have a season in which
temperatures are warm
and plants can grow.
But, rainfall is very low
and plants have little
available water. Desert
plants evolve to handle
this situation.
Biomes – Desert Biome
Chihuahuan desert
Sonoran desert
Leaves in a desert: small leaves,
no leaves, long narrow leaves
pointed upwards –why?
Climate causes plants to adapt
and evolve in such a way that
they uniquely fit the temperature
and precipitation of the area in
which they grow.
Animals adapt to both climate
and to the plants available to
them for food and cover.
Biomes – Temperate Forest

Temperate Forest Biome Characteristics
Climate characterized by 1) plentiful precipitation,
2) distinct seasons, 3) rain in summer and snow
in winter, 3) warm temperatures in summer and
cold in winter
Temperate Forest
A cool and moist
environment. Adequate
water available. But
trees have to adapt to
cold winters. Have to
survive freezing
temperatures that can
kill plants.
Biomes – Temperate Forest
Leaves in a temperate forest: conifer trees have tough
‘needle’ leaves, other trees loose their leaves in winter
and re-grow them every spring –why?
Biomes – Temperate Rain Forest

Temperate Rain Forest Characteristics
Climate characterized by 1) abundant rainfall
averages 60” - 200” per year, 2) summer fog
provides 7-12” ppt per year, 3) moderate
temperatures both summer and in winter
Temperate Rain
Forest
Moderate temperatures
and a great deal of rain.
A very shady and damp
environment. Trees have
enough water, and do not
have harsh winter
temperatures.
Get the graph
Biomes – Temperate Rain Forest
Abundant rainfall and a year-long growing season
means these forest can have ‘Giant’ trees.
Biomes – Grassland Biome

Grassland Biome: Characteristics
Climate characterized by 1) about 10 – 25 inches
annual rainfall, 2) drought!!!, 3) summer is hot
and winter is cold
Grasslands
There is more rain in a
grassland than a desert,
but not enough rain to
support trees. ‘Rule of
thumb’ is that when
average annual rainfall is
below about 30 inches,
the area will be a
grassland (prarie).
Biomes – Grassland Biome
There are three types of prairie in
North America. As precipitation
increases from 10 to 25 in, per year,
different types of grasses grow.
Shortgrass prairie, Midgrass Prairie
Tallgrass Prairie
Look at handout
on rainfall
Climate and Biomes in North America

Students: what you should be able to do








Draw a simplified map with the geographic patterns of
temperature and precipitation in the United States
Use the internet to find climate information on precipitation and
temperature for your area
Create a climate diagram, using the proper labels
‘Read’ a climate diagram and understand what it tells you about
the climate of a location
Demonstrate that you understand that climate is the most
important factor in determining ‘which plants and animals live
where’
Understand the term ‘Biome’ and be able to list 3 biomes in North
America
Locate the tribal colleges participating in this course on a map
Be able to give a general description of the climate and biome of
each school

Miscellaneous additional slides
Climate and Biomes in North America