Geography 417
California for Educators
Weather, Climate and Soils
Introduction
Of what
importance is the weather, climate and soils to
Californias growth and development?
Climate
How would you
characterize California's climate(s)?
What three factors are primarily responsible for the
climate in any one location?
I. Latitude
Latitude
determines both sun angle (intensity) and daytime length, factors in the amount
of InSolAtion.
Sun Angle
Northern Border 24.5 to 71.5 degrees
Southern Border: 34 to 81 degrees
Atmospheric Pressure
What other
weather condition does the intensity of sun affect?
The amount of InSolAtion is responsible in large measure for the
conditions of atmospheric pressure.
Air Pressure as an Imaginary Column of Air(fig)
Air Pressure
What device is
used to measure atmospheric pressure?
If this devices
reading falls, what does that signal to its reader?
What types of
weather might one expect?
Mercury Barometer (fig)
High and Low Pressure
Air that is hot
rises, creating low pressure.
Air that is cool
sinks, raising the barometer.
Rising air will
create clouds sometimes.
Descending air
warms as it sinks and produces clear skies.
Clear skies may
mean cooler temperatures.
Winds always move
from high pressure towards low pressure.
Wind Direction and Pressure (fig)
California in Global Pressure Context
The winds that blow
over California often are created by conditions that may exist thousands of
miles away, along the equator or near the North Pole.
Greater Insolation over the equator creates enormous lows there and
big high pressure zones not far from California.
World Air Temperature Patterns-January (fig)
World Air Temperature Patterns- July (fig)
July Pressures and Winds (fig)
July Pressures and Winds (fig)
January Pressure and Winds (fig)
January Pressure and Winds (fig)
Ideal Global Surface Winds (fig)
The ITC and Subtropical Highs (fig)
Global Heat Transfer and Hadley Cells (fig)
Global Circulation
See .mov clip on global circulation.
II. Continental and Marine Climates
Climate is also
greatly affected by the proximity of a location to an ocean.
The prevailing
temperature of nearby ocean currents also figures into the climate of adjacent
territories.
Inland locations
generally have a continental climate and seaside locations have marine
climates.
Marine climates
demonstrate modest seasonal and daily temperature swings.
Continentality
Continentality
Annual Temperature Ranges
Ocean Currents
Like the air,
differences in temperature and the rotation of the earth move bodies of water.
Water is also
blown along at the surface by wind.
Gulf Stream
Current and the California Current
Upwelling off
Point Arguello and Pt. Conception
Good for
what? Bad for what?
Ocean Currents (fig)
II. Elevation and Climate
Gravity affects
air, pulling it down, compressing and heating it. Air at higher altitude is less compressed and
feels cooler.
Air cools about
3.5d per 1000 feet.
It may be 100 in
the valleys around LA and only 60 in the nearby highlands.
Why do you still
get sunburned in the mountains?
Temperature Inversions
Sometimes the
rule about warm air below and cold air above is reversed, creating inversions.
Two types: Winter
low level and the summer upper level variety.
California has
famous inversions.
Winter inversions
affect the distribution of both wild and domestic plant species. Why?
Temperature Inversions (fig)
Low Level Temp. Inversion (fig)
Temperature Inversions (fig)
On the mountains..
What do the
mountains experience during these inversions?
What might you
see standing on a mountain looking down into the LA/SFV valleys?
Seasonal Changes in Weather
Its not endless
summer out here.
Winters can be
cold and rainy, cold and dry or at least very different from the hot and dry of
summertime.
Summertime
High pressure in
the Eastern Pacific dominates, driven by 1___, 2_______.
This high causes
not only the drought conditions common here but also it is responsible for the
prevailing _______.
These _____ push
the California current southward along the coast.
The cold ocean
prevents the wind from picking up______?
Relative Humidity and Temp (fig)
Local Winds
A small scale
version of how this works can be witnessed at the beach day and night.
Keep in mind that
water heats up and cools down more slowly than land.
Similar effects
occur with mountains and valleys
Santa
Ana Winds.
Land and Sea Breezes (fig)
Land and Sea Breezes (fig)
Mountain-Valley
Breezes
Wind Farm in CA (fig)
PRECIPITATION
There are
basically three types of precipitation: convectional, cyclonic and orographic.
You should know
how each is generated, where its likely to happen in
California and when.
Annual Precipitation Map
Winter Storms
The East Pacific
High moves southward.
The jet stream
and Rossby waves sometimes bring pools of the
Aleutian low down toward CA.
There is abundant
opportunity for frontal storms to develop.
A. Cyclonic or Frontal
This type of
precipitation is created when air masses of different temperatures come in
contact.
Cold fronts may
bring a line of heavy clouds and rain that last only hours.
Warm fronts may
bring drizzly conditions for days.
Our winter
precipitation in Southern California is mostly frontal, but Northern California
gets this more frequently.
Frontal Boundary (fig)
Frontal Boundary (fig)
B. Convectional Precipitation
These types of
showers are created when an air mass rises due to instability in the
atmosphere.
These types of storms
are more common in the summer and in inland areas, out in the desert. Called mistakenly
monsoon.
Very
common in the Midwest and Southeast during the summer.
Dont make it to
the coast.
Convection
Autumn Precipitation
Because the ocean
takes longer to cool during the fall than the land, high pressure forms over
the Great Basin, shifting the wind pattern from the common summer pattern.
What is the
result, especially here in Southern California?
What about
interior California?
C. Orographic Precipitation
A
consequence of our seaside location and mountainous terrain.
Air that is
forced to higher elevations by prevailing winds is forced to expand, lose
energy, cool and if it is filled with water vapor, condense and produce
precipitation.
Once over the
mountains, it may descend, compress, heat and begin drying out leeward
locations in the rainshadow.
Orographic Effects (fig)
Orographic Lifting (fig)
Orographic Precipitation (vid)
Santa Ana Winds (fig)
(Chinooks, Foehn Winds)
Wildfire (fig)
AIR POLLUTION
The peculiar
mixture of air pressure, temperature and topography along with 10 million
people make Southern California, especially LA, one of the worst places
anywhere.
Most other
valleys around CA suffer too.
Ozone.
Government to the
rescue!
CALIFORNIA CLIMATES
California has
more climate types than any other state.
They include:
Mediterranean
Marine West Coast
Desert (High and Low)
Montane (Mountain)
World Precipitation E
(fig.)
World Precipitation West
(fig.)
Mediterranean
Has a mildly wet winter and a dry summer.
Mild
temperatures year round.
Rain is mostly
cyclonic and during the summer the subtropical high dominates.
Also prevails in
the Mediterranean areas,, Santiago Chile, Perth
Australia and Capetown South Africa.
Specialized crops
and vegetation prevail.
Consider the
effects on migration and agricultural competition.
Monterrey, CA
Climograph (fig.)
Marine West Coast
Very
rainy, especially in winter and with mild to cool temperatures year-round.
Only
on the west coasts and affected by the prevailing westerlies
passing over oceans.
Very
rainy, especially in the winter and generally cool.
San
Francisco North to Seattle, Western Europe, Southern Chile and New Zealand.
Frequently
forested and cropped with rain-tolerant crops.
Soils may be poor.
Vancouver, BC
Climograph (fig.)
Mediterranean and West Coast W (fig.)
Mediterranean and West Coast W (fig.)
Dry Midlatitude
May get very hot
and very cold
Rainfall is small
and varies only slightly throughout the year.
Many of these
regions are rainshadowed or continental.
Great
Central Valley, Interior Asia and North America, as well as Patagonia.
Short
grass prairies is natural, but
wheat is cropped on most of the flatter areas.
With irrigation,
much else is cropped.
Peublo, CO
Climograph
(fig.)
Alpine Climates
California has
many locations that altitude plays the dominant role in the character of the
climate.
EL NINO
Created
when prevailing ocean temperatures are inverted over the Pacific Ocean.
Happens
every 5-8 years.
Followed
by La Nina.
May
explain huge massacres in pre-historic Americas.
Deep Ocean Currents (fig)
El
Nino, ITC and Currents (fig)
El Nino (video)
Global Warming and the Greenhouse Effect
Is the planet
warming or not?
Yes. But Why?
Is the warming
planet the result of CO2 and other greenhouse gases such as CH4 (methane) and
CFCs and NO (nitrous oxide)?
Is it a result of
changes in solar activity?
Is it a result of
a wobble in the earths rotation?
Is it a lack of
volcanic activity?
CO2 and Temp (figure)
The Temperature Record
There are dozens
of means to measure past climatic trends.
Varying results
have been posted.
Junk science and
endowed science.