Download File - Mr. Summers Science

What do you
expect to happen
to the blue line?
The red line?
 Determines
amount of water vapor in air
 What
might cause this?
 Evaporation!
 Rate
of evaporation exceeds rate of
condensation as temperature rises
 Amount
of water vapor in the air
Relative humidity
 Amount of water vapor in air
 This is the maximum amount of water
vapor possible at that temperature
 Given as a percentage
 Process
by which a gas (like water vapor)
becomes liquid
 Occurs when temperature drops below
dew point
 Temperature
at which air becomes
saturated and produces dew
A
collection of millions of tiny water
droplets or ice crystals
 Form as warm air rises and cools
 As cloud temperature drops below dew
point, condensation occurs
A
large body of a specific air type
 Has the properties of the surface
where it developed
m
 Maritime
c
 Continental
T
 Tropical
P
 Polar
A
 Arctic
 Boundary
 Four
between two air masses
types:
› Warm
› Cold
› Occluded
› Stationary
 Warm
air catches up to the cold air
 Warm air gently rises over cold air
 Cold
air catches up with warm air
 Cold air slams into warm air
 Quick vertical rising of warm air
 THUNDERSTORM!
 Two
cool air masses merge and force
up the warm air between them
 Strong winds
 Usually lots of
precipitation
 When
pressure is equal between the
cold air mass and warm air mass
Clouds
Cirrus clouds
 Ice clouds
 Over three miles
high
 Below freezing temperatures even in summer
 Wind currents twist and spread the ice crystals into
wispy strands
Cumulus
 Fluffy, white cotton ball clouds
 “Fair weather clouds”
Stratus
 Thin, white sheets covering whole sky
 Can appear to be fog
Special clouds
 Orographic
Get shape from mountains or hills that force the air to
move over or around them
 Refers to the transport of some property of the

atmosphere or ocean, such as heat, humidity or salinity.
Lenticular


Shaped like lenses
Shape comes from hilly terrain or the way air rises
Mammatus
 Mammatus is a term applied to a pattern of
pouches hanging underneath the base of a cloud,
often a cumulus or cumulonimbus.
 These pouches, typically measuring about half a
kilometer in diameter, are often ragged, but may
appear smooth.
 Their color is normally a bluish gray, the same as
that of the host cloud, but direct illumination from
the setting sun and other clouds may cause a gold
or reddish cast.
Mammatus
Mammatus can persist anywhere from
minutes to hours, diffusing and
disappearing over time.
The mechanism of their production is
poorly understood and has been little
studied. The presence of very dry air
beneath the cloud base is known to be a
factor.
They are often associated with storms.
Nacreous clouds
 Nacreous clouds only occur at high polar latitudes
in winter, requiring temperatures less than minus
176 degrees Fahrenheit (minus 80 degrees Celsius).
 A weather balloon measured temperatures at minus
189 degrees Fahrenheit (minus 87 degrees Celsius)
on the day the photo was taken.
Nacreous clouds
 Resembling mother-of-pearl shells,
they are produced when fading light at
sunset passes through water-ice
crystals blown along a strong jet of
stratospheric air more than six miles
above the ground.
Nacreous clouds
Effects of Cloud Cover
 During the day, Earth is heated by the sun
 Clear skies  more heat to surface  warm temp
 Cloudy skies  less heat  cooler temp
Forecasting and Clouds
 During the day, cloud cover makes for colder
temperatures.
 What happens with cloud cover at night?

This is when it traps heat in, resulting in a slower decrease
PRECIPITATION
FORMATION
Rain
 Develops when growing droplets become too
heavy to stay in the cloud.
 Can develop into ice crystals if cold enough
 As ice crystals pass into warmer air, the flakes
turn into rain drops
Hail
Hail forms in cumulonimbus clouds as a
strong updraft carries raindrops and ice
crystals back up into the cloud where
temperatures are below freezing and
raindrops will freeze into sleet or graupel
(frozen raindrops).
It is then carried up through the cloud
where millions of supercooled water
droplets collide with the ice surface and
are instantly frozen, causing the graupel to
become larger.
Hail
 When the now larger graupel or hailstone reaches
the top of the cloud, it begins to fall back
downward where the updraft is weaker.
 The hail falls back down into an area where the
updraft is stronger and this cycle begins again with
the hailstone growing another ring of ice.
 This cycle will continue and the hailstone will
become larger until finally it becomes too heavy
for the updraft to carry upward.
Key points of hail
 Layers continually grow on ice
 Stronger updraft creates bigger hail
Ice storm dangers
 Lines freeze
 Layers of ice
Freezing rain
 Causes terrible driving conditions
 Supercooled rain that freezes when meeting
cold surfaces
 Found in narrow
band on cold side
of warm front
 Temp just at or
just below freezing
The Freeze
 Supercooled drops aren’t frozen until they hit
the ground
Stationary Fronts
 Produces freezing rain
 Arctic air mass are shallow
 Produces severe
winter weather
Effects of Snow Cover
 Earth’s surface usually absorbs sunrays
 This warms the air near the surface
 Snow will reflect the rays, some snow melts
 Fewer rays reaching surface means the Earth
warms slowly
Forecasting and Snow
 When snow is present:
 Forecast lower daytime temperatures
 At night, snow on ground gives off heat
 Rapid cooling occurs
 Forecast cooler than
if there was no snow
Air Currents
What are the
two types of
wind?
Air Currents
 Wind: moving air
 Air always moves from High Pressure  Low Pressure
 Two main types of wind:
 Local Wind
 Global Wind
 A Video
More on air
 Air always move from warmer to cooler
 Temperature advection refers to change in temperature caused
by movement of air by wind
 Forecast using advection:
 Involves looking at wind direction and upstream temperatures
(direction from where the wind is blowing)
 Warm advection, expect warming trend
 Cold advection, expect cooling trend
Local Wind
 Moves short distances
 Blows from any direction
 Examples:
 Sea breeze
 Land breeze
Global Wind
 Long distance
 Specific travel direction cause by Coriolis effect
 Once air has been set in motion it follows deflection
from its path. This is a result of the earth’s rotation.
Global Winds
 Examples:
 Doldrums
 Trade Winds (30º N & S)
 Westerlies (30-60º N & S)
 Polar Easterlies (Poles-60º N & S)
 Jet Streams: narrow belt of high-speed air
(250 mph)
Zones of the Earth
F.Y.I.
 Doldrums comes from the Old English word
meaning “foolish.”
 People were considered foolish if they were
caught sailing in this area.
 Trade Winds got their name because people used
them to sail between Europe and America to
trade.
Air Current Measurement
 Weather Vane:
 Direction
 Anemometer
 Speed
Effects of Wind
 At night, Earth’s surface cools by
radiating heat toward space.
 On a windy night, warmer air
above mixes down to surface.
 This occurs because winds are
faster above than on surface.
Forecasting and Wind
 On a calm night, the maximum surface cooling takes place
 On a windy night, warmer air mixes downward to surface
 This prevents the temperature from dropping quickly
 Forecast Tip:
 Forecast slightly warmer on a windy night vs. a calm night
Energy Transfer
Energy transfer
 Most of Earth’s energy comes from the sun
 What happens when the energy gets here?
 20% is absorbed by the atmosphere
 30% is reflected back
 50% absorbed by the surface
Three types of energy transfer
 Radiation
 Conduction
 Convection
Radiation
 Transfer by heat waves
 Example:
 Your skin starts to feel warm after you have been in the sun
Conduction
 Transfer of thermal energy from one material to another by
direct contact
 Example:
 Touching a hot pan on a stove or barefoot on a hot sidewalk
Convection
 Transfer of thermal energy by the circulation of liquid or gas
 Example:
 Heating your house, lava lamps, heated pools
ATMOSPHERE
Atmosphere
 Blanket of gases around the Earth
 Protects us from harmful rays
 Always changing due to people breathing, trees,
and cars
Composition
Percentage
Elements
 78%
 Nitrogen
 21%
 Oxygen
 1%
 Others
The other gases
Mostly composed of:
- Water vapor
- Carbon dioxide
- Argon
The layers
Divided by temperature:
 Thermosphere
 Outer layer
 Mesosphere
 Lowest temperatures
 Stratosphere
 Ozone Layer
 Troposphere
 Weather occurs
 Ground Level
AM Radio
 The ionosphere reflects AM radio waves.
When it is clear outside, the waves can be
transferred around the world.
Troposphere
 Contains 90% of the atmosphere’s total mass
 Almost all of the Earth’s
CO2,water vapor, cloud,
air pollution, weather,
and life forms are here
Temperature Variation
 Due to solar energy absorption
 Warmer = more energy absorbed
 Cooler = less energy absorbed
 Thunderstorms
• Thunder, lightning
• Gusty winds, heavy rain, hail
 Form
when warm,
humid air rises in an
unstable environment
 Estimated 2000 thunderstorms in
progress, where are they located?
 Violent
windstorms that take form of a
rotation column of air called a vortex.
This vortex extends downward from a
cumulonimbus cloud.
 Most tornados form in association with
severe thunderstorms.
 Whirling
tropical
cyclones that
produce winds of at
least 119 km/h
 Most occur between
5 and 20 degrees
north and south of the
equator.
 North Pacific
averages 20 per year.
 Usually
occur in late summer when the
water temperatures are warm enough to
provide heat and moisture to the air.
 The eye is a zone of scattered clouds and
calm averaging about 20 km in diameter
at the center of a hurricane
 Eye wall is a doughnut shape area of
intense cumulonimbus development and
very strong winds that surround the eye.
PRESSURE AND THE ATMOSPHERE
Atmospheric Pressure
 Have you ever wondered why your ears pop
on an airplane or in an elevator?
 This occurs when the pressure outside your
ears becomes equal to the pressure inside
your ears.
Atmospheric Pressure
 Gas has mass
 Gas takes up space
 Atoms in the
atmosphere are
pushed together
by the mass above
 Definition:
 The force air exerts on objects it contacts
Factors of air pressure
 Elevation
 lower level = higher pressure
 Temperature
 cold air sinks so pressure increases
 Density
 high density = high pressure
Q & A
 If cold air sinks and warm air rises,
Why is it cold at the top of a mountain?
 Not as many molecules are at available
 Lower density of air molecules
 Few molecules are available to transfer heat
Pressure and Storms
 High pressure = fair weather
 Low pressure = stormy weather
Measuring the pressure
 What unit of measurement is used on TV?
 Inches of Hg
 What do meteorologists use?
 Milibars = mb
 How do we
measure it?
 barometer
What percentage of
the Earth’s surface is
covered by water?
How much does the
atmosphere hold?
Evaporation
 What is evaporation?
 Water transfer into the atmosphere
 About 80% comes from oceans
 About 20% comes from inland waters
and vegetation
Evaporation
 Most evaporated water exists as gas outside of clouds
 In what type of temperature is evaporation more
intense?
 Warmer
temperatures
Condensation
 What is condensation?
 Conversion of gas into liquid
 Occurs when warm air rises, cools, and
loses capacity to hold vapor.
Condensation
 Upward motions that generate clouds can be produced
by:
 Convection in unstable air
 Convergence from cyclones
 Lifting of air by fronts
 Lifting of air by topographic features
Transport of water
 Moisture transports as clouds
 Movement by jet stream or circulation of breezes
Precipitation
 Water transfer from clouds back to surface
 Forms include:
 Hail
 Snow
 Sleet
 Freezing rain
Groundwater
 Water that is beneath the surface in one of two soil
layers
 Zone of aeration  nearest surface
 Zone of saturation  next layer down
Reservoir
 A pond, lake, or basin, either natural or artificial, for
the storage, regulation, and control of water.
 Luther Aadland
demonstrates this
Ogallala Aquifer
 Massive supply of water
 Possible contamination
 Reality of threat
Transpiration
 Evaporation of water from leaves and stems of plants
 Accounts for 10% of evaporation
Runoff
 Movement of land water to oceans
 Consists of precipitation
that does not evaporate
 Does not transpire
 And does not enter
the groundwater system
OCEANS
THE FORMATION
After the Earth cooled, water vapor in the
atmosphere condensed, causing rain to fill the
first ocean.
 Currently there are four major divisions:

 Arctic
Ocean
 Indian Ocean
 Atlantic Ocean
 Pacific Ocean
ABOUT THE WATER
Salinity: measurement of dissolved solids in
liquid
 The ocean salinity is 35 g per 1000 g
 Salt is the majority
of dissolved solid

FACTORS AFFECTING SALINITY
Evaporation
 Circulation
 Freshwater inflow

MOVEMENT OF OCEAN WATER

Surface currents:
 Stream
like movement of water at or near the
surface of the ocean
 Affect climate by
cooling or heating
the coastline
DEEP CURRENTS
Stream-like movement of water far below the
surface
 Deep and surface
currents are caused by

 Convection
TIDES
Daily movement of ocean water that changes
level of surface
 High tide and low tide are dependent upon the
moon’s orbit

TIDE INFORMATION
The moon’s pull is strongest on the side of the
Earth facing the moon.
 This causes a bulge on the side facing the
moon and directly opposite. (High tide)
 The sun can affect tides.
 Tidal range is the difference between low and
high tide.

SPRING TIDE
When the sun, moon, and Earth are aligned
 Maximum daily tidal range

NEAP TIDE
When the sun, Earth, and moon are
perpendicular
 Minimum daily
tidal range
