Weather

1
Weather

• An Overview

2
Atmosphere

• Is a mixture of the gasses that surround the
  Earth.
• The atmosphere gives us the air we breath as well
  as protects us from some of the suns harmful
  rays.
• The atmosphere is also the location where a lot
  of the weather phenomena that we will be learning
  about happens.

3
Air Pressure

• Is the measure of the force with which air
  molecules press on the surface.
• When your ears pop the pressure inside your ears
  and outside your ears become

4
Altitude

• Is defined as the height of an object above the
  surface of the Earth.
• As altitude increases air pressure decreases
• Why is this?

5
Layers of the atmosphere

• Based on temperature the Earths atmosphere is
  divided into 4 layers
• 1) Troposphere
• 2) Stratosphere
• 3) Mesosphere
• 4) Thermosphere

6
Troposphere

• Lowest layer of the atmosphere
• Densest atmospheric layer
• Earths water vapor, air pollution, clouds,
  weather, and life forms are found at this layer

7
Stratosphere

• The air is very thin and contains very little
  moisture
• Temp approx. -60 C degrees
• In this layer the temperature rises with altitude
  because of ozone which is a gas that heats up the
  atmosphere

8
Mesosphere

• Coldest layer can be as low as -93 degrees C
• Large wind storms can take place with wind speeds
  reaching more than 150 mph

9
Thermosphere

• The upper most atmospheric layer in which the
  temperature can reach 1700 degrees C.
• Very few molecules at this layer
• Picture to right shows heat at this layer

10
Heating of the Atmosphere

• Heating of the atmosphere takes places in 3 ways
• 1) Conduction
• 2) Convection
• 3) Radiation

11
Radiation

• This is a method of heat transfer in which heat
  travels through empty space
• The best example of this is the suns rays heating
  up the Earth. The heat will travel through outer
  space (empty) reach our planet and heat up the
  surface

12
Conduction

• Is the transfer of thermal energy from one
  material to another by direct contact
• Example would be walking on the sidewalk and
  heating up your foot from the heat that has built
  up on the ground

13
Convection

• Transfer of thermal energy by circulation or
  movement of a liquid or a gas
• For example air is heated and it rises then it
  cools and it sinks. This circular up and down
  motion pushes atmospheric gases on our planet .

14
The Green House Effect

• This is the process in which gases in the
  atmosphere trap thermal energy. Keeps the surface
  of the Earth much warmer

• Global warming This is when the Earths average
  temperature increases each year. Average
  temperature is the average of all the locations
  on earth during 1 whole year.

15
Wind

• Is very simply defined as moving air.
• It is created from differences in air pressure
  caused by temperature differences.
• Usually there is greater pressure at the poles
  and less at the equator. There fore wind usually
  moves from the poles toward the equator.

16
Coriolis Effect

• The curving of moving objects, such as wind, by
  the earths rotation is called the coriolis
  effect.
• Cont. on page 404
• Read 402 - 407
• Page 407 questions 1-4

17
Types of Winds

• Trade Winds winds that blow from 30 degrees
  latitude to the equator
• Westerlies wind belts found in both the northern
  hemisphere and southern hemisphere between 30 -
  60 degrees latitude
• Polar Easterlies wind belts from the poles to 60
  degrees latitude

18
The Jet stream

• The jet stream is very high speed band of air
  that blows in the troposphere and lower
  stratosphere
• The jet stream can reach wind speeds of up to 250
  km / hr
• This stream of air switches direction often, and
  in doing so steers storms / fronts across our
  country

19
Jet Stream
20
Pollution

• Primary pollutants put in the air by human or
  natural activity

• Secondary Pollutants This type of pollutant
  reacts when two primary pollutants react to form
  a new secondary pollutant

21
Acid Precipitation

• When fuels get burned some of the remnants go up
  into the air where it mixes with water vapor and
  then comes down as acid rain. This rain can
  weather metal, wood (ect.) at and advanced rate.
• Ex. Statue of liberty, Bridges

22
Assignment

• In the past few decades Pollution has become a
  major problem for our country. Please write an
  essay stating what you would do if you had an
  unlimited budget and where in charge of
  environmental policies in our country. How would
  you go about fixing this major problem?

23
Water Cycle

• This relates to the continuous movement of water
  from lakes / rivers to clouds to the ground and
  back up again
• Vocabulary condensation / vaporization

24
Humidity

• Is defined as the amount of water vapor or
  moisture in the air.
• relative humidity Is the amount of moisture in
  the air compared to the maximum amount of
  humidity it can hold at a certain temperature

25
Dew Point

• Is defined as the temperature air must cool to be
  completely saturated.

26
Clouds

• A cloud is a collection of millions of tiny
  little water droplets or ice crystals which are
  suspended in the air
• In this next section we are going to learn about
  the different types of clouds

27
Cumulus Clouds

• Puffy white cloud that tend to have a white
  bottom ( cotton balls)
• These clouds form when warm air rises
• They usually represent good weather, unless they
  get very large they can represent thunderstorms

28
Stratus clouds

• This type of cloud forms in layers
• This type of clouds covers large areas of the sky
  usually blocking out the sun
• Caused by a gentle lifting of a large body of air
  into the atmosphere
• NIMBOSTRATUS clouds that are stratus in origin
  however dark in color. They usually produce light
  to heavy rain

29
Cirrus Clouds

• Thin feathery white clouds formed at high
  altitudes
• These types of clouds form when the wind is
  strong
• They may represent bad weather If they begin to
  thicken and lower in altitude

30
Precipitation

• Is water in liquid or solid form that forms from
  the sky to the surface of the Earth
• There are four major types of precipitation
• Rain, Sleet, Snow, Hail
• In order for a cloud droplet to form as
  precipitation it must increase its size 100 times

31
Snow / Sleet

• Snow forms when water vapor is so cold that it
  falls in solid form as snow
• Sleet forms when rain falls through a layer of
  freezing air
• If the rain does not freeze till it hits the
  surface then it forms something called glaze or
  (ground ice)

32
Hail

• Solid precipitation that forms as balls or lumps
  of ice
• Usually forms when gust of air carries rain
  droplets to a high ,, cold altitude where it
  freezes and then falls to the Earth as a ball of
  ice called hail