Energy from the
SUN – INcoming
seasons, it heats
our world, some
parts more and
some less and this
The electromagnetic spectrum includes
visible light, as well as X-rays, ultraviolet
rays and infrared rays.
Climate is the average
over a long period of
Water Budget – a
system of accounting
for moisture income,
storage, and outgo for
the soil in a specific
Humid climates are those in which the total amount of
precipitation is greater than the total amount of Potential
Evapotranspiration (Loss of water to atmosphere)
Arid climates have significantly more total Potential
Evapotranspiration than Precipitation
highest and lowest
Warmer than Ave.
Colder than Ave.
Kansas, NE, IA,
San Francisco, LA,
Uneven heating of the
global wind belts
and pressure belts.
belts” determine the
wetness or dryness
of a particular
where air is rising
regions are areas
that lack rainfall
The "Global Conveyer Belt" shows how the oceans move
energy from the tropics to the poles and back again in order
to moderate Earth's climate. This is accomplished through
long-term ocean circulation.
fact: It takes up
to 1000 years
for water to
A warm ocean current resulting from a reversal of
the ocean current in the Pacific which results in
climate variability around the globe.
Orographic Effect – Mountains act as barriers
to prevailing winds. As the wind hits the
windward side of a mountain, the air is forced
up, cools, condenses and forms clouds with
Windward side – Side of the mountain that is
exposed to the wind. WET
Leeward Side – Descending air warms and it
holds more moisture, making it DRY.
*Why does rising air cool?
*As air temperature decreases,
its ability to hold water___DECREASES______
*Why does falling air warm?
Weather = the condition of the atmospheric variables, such as
temperature, air pressure, wind, and water vapor, at a particular
location for a relatively short period of time.
Direct result of TILT &
parallelism in orbit
distribute energy from
vertical to oblique rays
of energy over broader
Moisture Conditions (Precipitation & Humidity)
Wind (Speed & Direction)
Note: In the USA we still
use degrees Fahrenheit –
the rest of the world
measures in oCelsius
Complete the questions in the note packet while
Composition of the lower atmosphere
1. Nitrogen = 78% used by bacteria in soil
to make nitrates
2. Oxygen = 21% used by humans and
animals for respiration
3. Argon = 0.84%
4. Carbon Dioxide = 0.03% used by green
plants to make food
5. Others = 0.01% which include:
Helium, Hydrogen, Ozone, Krypton, neon and xenon
6. Also: water vapor, dust particles and pollution
What is Ozone?
– we breathe O2
occurs naturally in trace amounts in the
protects life on Earth from the Sun’s UV
is created naturally when sunlight splits
apart O2 into single O atoms – these then bond to
form more O2 or O3
The ozone molecules are randomly scattered
among other particles in the stratosphere layer
Ozone molecules are exceedingly rare: In every
one million molecules of air, fewer than 10 are
Filters out harmful UV radiation, which can cause
skin cancer, cataracts, faster aging & weakened
UV is also harmful to plants & marine life and it
can disrupt the food chain
CFC – chlorofluorocarbons, which are used in:
Coolants in refrigerators
Propellants in aerosol cans
Electronic cleaning solvents
Ground-level ozone triggers chest pain, nausea,
bronchitis, reduced lung capacity, and aggravates asthma
Air Quality Index
An index for reporting daily air quality
Focuses on health effects that can happen within a few
days of breathing polluted air
Used for: ground level ozone, particulate matter, carbon
dioxide, sulfur dioxide, and nitrogen dioxide
-any substance in the atmosphere that is harmful ( usually produce long term health
effects and can cause death )
Main Sources – burning fossil fuels ( coal and petroleum )
Ex: SOx, CO ( carbon monoxide ), lead, various hydrocarbons
Acid Rain ( precipitation ) – side effect of air pollution
- gases from burning fossil fuels combine with water in the air to
produce acids, then falls back to the earth as precipitation
Long Term effects: kills fish, soil contamination, destruction of plants,
Mt. Mitchell, NC
Temperature Inversion ( very serious problem )
In order for this reaction to occur, it must be
extremely cold. Conditions for this reaction are
perfect over Antarctica in the winter months.
Can we fix it??
The ozone hole will fix itself given enough time
Many major countries, including the U.S., have
placed heavy restrictions on ozone-polluting
The false-color view
of the monthlyaveraged total ozone
over the Antarctic
pole. The blue and
purple colors are
where there is the
least ozone, and the
yellows and reds are
where there is more
6% reflected from
20% reflected by clouds
Reflected by Earth’s
3% Absorbed by clouds
51% Absorbed by Earth’s
16% Absorbed by
Short wave energy (UV) from the Sun comes in
and heats the Earth
As heat reradiates up from the earth, it is emitted
in the form of LONG wave energy (infrared)
The long wave energy becomes trapped by gases
in the troposphere
This trapped gas warms the air much like your
car on a hot day.
Transfer of heat within solids
atoms are closely packed.
Transfer of heat in liquid or
results from differences in
The emission or giving off of
Heat in the atmosphere is recorded as a
temperature reading and can then be plotted on a
map to see a picture of change.
ISOTHERMS are lines that connect points of equal
temperature. Showing temperature distribution in
this way making patterns easier to see.
Why do the isotherms seem to run E – W across the map?
LAND vs. WATER
Land heats up and cools faster than water
DARK vs. LIGHT
Darker colors tend to absorb more insolation than they reflect.
Surfaces with lighter colors tend to reflect more insolation than
Smooth vs. Rough
A surface which
has a rough or
will absorb more
The primary source of moisture for the atmosphere
are the OCEANS.
Other sources include:
Lakes, Rivers, streams
Moisture in the atmosphere exists in all three
1) Gas – known as water vapor
2) Liquid – tiny droplets suspended in the air that
3) Solid – tiny crystals suspended in the air that
HUMIDITY is the general term used to describe the
amount of water vapor in the air
Temperature determines the amount of water
vapor the air can hold.
As air temperature
INCREASES, the amount
of water vapor the air can
humidity in the
At 350C, a cubic meter of
air can hold 35 g/m3 of
Temperature – As temperature increases,
Wind – As wind increases, evaporation increases
Surface Area – As surface area increases,
Humidity – As humidity goes UP, evaporation rates
The temperature to
which air must be
cooled to reach
If the air temp drops down
to the dew point,
condensation will occur.
The dew point can tell us
how high clouds will form.
Clouds form where
condensation is occurring.
The drier the air, the faster/more evaporation
will occur resulting in greater/more cooling. In
turn, the difference in temperature between the
dry bulb and wet bulb will be greater/more.
The more humid the air, the LESS evaporation
will occur resulting in LESS cooling of the wet
bulb thermometer. In turn, the difference in
temperature between the dry bulb and wet bulb
will be LESS
At saturation (100% humidity), the temperature
difference between the dry bulb and wet bulb
would be zero and precipitation will usually
Maximum amount of water vapor the air can hold
at a given temperature.
The actual amount of water vapor in the air is the
Relative humidity tells "how full" the air is with
water. It is expressed in %. 100% is full and can't
hold any more. It is saturated.
Warm Air = higher humidity (wet)
Cold Air = low humidity (dry)
Changing Air Temperature
If temperature increases and moisture in the air remains
the same, relative humidity will decrease.
Changing Absolute Humidity
If moisture content of the air increases and
temperature stays the same, relative humidity will
Using the chart to determine Dew
Point & Relative Humidity
It’s easy; if…..
You have ½ a brain
Do your practice!
The “Dry Bulb”
Don’t let it fool you.
is just a thermometer.
It measures the air
The “Wet Bulb”
Has a little wet booty
tied to the bottom.
Gets cool when
A Dry Day…
A lot of moisture will
The wet bulb will be
a lot cooler than the
Difference between wet bulb &
dry bulb is 12 °C.
A Humid Day…
A little bit of moisture
The wet bulb will not
be much cooler than
the dry bulb.
Difference between wet bulb &
dry bulb is 6 °C.
Page of your notes has a chart
with Dewpoint (DPT) and
Relative Humidity (RH)!
Warning #1: Be sure to READ the correct chart:
DPT or RH
Warning #2: Dew Point Temperature IS NOT
“Difference between wet bulb and dry bulb”.
Warning #3: The wet bulb temp IS NOT the DPT.
Dry-bulb temperature is your air temperature.
The Dew Point Chart works the same way
Dew Point = 6°C
Now do the worksheet for homework on
the next page of your notes
si on &
R ising AIR
De a c
oi g t
Adiabatic Cooling As air rises, the
parcel of air
parcel of air
expands as it rises.
As it expands, it
temperature of this
parcel of air falls to
its dew point
water vapor in the
air condenses and a
cloud appears in the
Air pressure acts equally in all directions; it also exists
within any object containing air like a building, the
human body and “empty” bottles.
When you mess with the pressure – “bad” things
Factors/Variables that cause
atmospheric pressure to
Effect of temperature on air
As air temperature increases;
(air molecules move further
apart/become less dense) –
the air pressure decreases
c. Effect of moisture on air
As humidity increases,
air pressure decreases –
because when water
vapor molecules enter
the air, they replace
heavier air molecules
Effect of altitude on
(less air is above and
air is less dense
Isobars are lines that
connect points of equal air
pressure. Showing air
pressure distribution in
this way makes patterns
easier to see.
On U.S. Weather Bureau
maps, the interval
between isobars is 4 mb.
On weather maps, barometric pressure is
represented by a three-digit number to the upper
right of a circle; this circle represents a city on the
Rules to follow to determine the value of this
A decimal point is omitted between the last 2 digits on the
The number 9 or 10 is omitted in front of this number. If the
original number is above 500, place a 9 in front. If it is
below500, place a 10 in front. (Hint: use whichever will give a
result closest to 1000 mb)
Example: 053 – 1005.3
Components of Weather
High Pressure System: Anticyclone
Winds blow in a
and away from the
Caused by: More
dense air “falling”
Components of Weather
Low Pressure System: Depression
IN towards the center
Therefore – once they
get to the middle, there
is nowhere to go but
movement of air
parallel to Earth’s
All wind deflects to the
RIGHT in the
How is Wind Formed?
As air cools
it can no
Air rises and
cools in the
WIND moves from high to low
Uneven heating at Earth’s surface
Land vs. water
Poles vs. equator
Dark forest vs. snow field
Winds always blow
from regions of high
pressure to regions of
Winds are named
for the direction
that they come
The direction of the line always points to the center of the
circle (in this case pointing east) and indicates the direction
in which the wind is blowing at this location.
Each “feather” represents the wind speed –
Whole feather = 10 knots
Half feather = 5 knots
The speed of the wind is
determined by the difference in
Pressure gradient – difference in
air pressure ÷ distance between
As the pressure gradient
increases (isobars are very close
together), wind speed increases.
The coriolis effect –
Earth’s rotation on it’s
axis causes winds to be
deflected to the right in
hemisphere and to the
left in the southern
The unequal distribution
of Insolation causes
unequal heating of the
Earth which causes
differences in pressure
which result in winds.
Cooler air, being more
dense, sinks toward
Earth due to gravity,
causing warmer, less
dense air to rise
causes the Coriolis
Effect which results
in the three (or six)
cell circulation of
winds as illustrated
in your notes.
Components of Weather
What is an Air Mass?
An air mass is a large body of air in the
troposphere moving in a particular direction,
with the same temperature, pressure and
Components of Weather
Air Masses Affecting the U.S.
2. Types of Air Masses
Tropical – originates in the tropics (low
latitudes). Characterized by warm air.
Polar – originates in polar regions (high
latitudes). It is characterized by cold air.
Arctic – originates in ice covered arctic
regions (winter only). It is very cold and
It’s right here in ESRT
Continental – think LAND.
It is dry.
e. Maritime – think SEA. It is
3. Air masses are a combination
of temperature and moisture
Types of Fronts
Table is on page 26
Cold Air –moves fast
Cold air meets warm
air and mixes
Showers for long
Air is dense and hugs the
Lots of Clouds as air
“bullies” the warm air UP
Covers wide area
Brings intense change –
brief periods of stormy
Stationary Front: Warm and Cold air meet head on and neither gives way. Low pressure usually
A storm that generates lightning and thunder.
Frequently produce strong winds, heavy rain, and hail.
At any given time, there are an estimated 2000
thunderstorms in progress on Earth.
In the US, Florida and the eastern Gulf Coast region
experience the most activity.
Develop when warm, humid air rises in an unstable
Violent windstorms that take the form of a rotating
column of air called a vortex, which extends downward
from a cumulonimbus cloud.
The US experiences approximately 700 tornadoes each
Greatest occurrence is from April-June (but can happen
Most frequently in the Central USA! Unique…..
Measured using the Enhanced Fujita Scale.
The Birth of a Tornado
The Birth of a Tornado
A hurricane is a heat engine that gets its energy from warm
ocean water. These storms develop from tropical depressions
which form off the coast of Africa in the warm Atlantic waters.
When water vapor evaporates it absorbs energy in the form of
heat. As the vapor rises it cools within the tropical depression, it
condenses, releasing heat which sustains the system.
•A tropical depression becomes a hurricane when its sustained
recorded winds reach 74 mph.
•Although hurricane forecasting has improved over the years
tremendously, the path of these storms may only be
What do you
mean there are
no more Earth