Why do we have
Download
1 / 44

Why Do We Have - PowerPoint PPT Presentation


  • 84 Views
  • Uploaded on

Why Do We Have. WHY DO WE HAVE THE WEATHER ?. Just think about it! Why is there wind? Why does it blow from one direction one day and another the next? Why is it rainy one day and dry the next? How come it’s cold in the winter? How can we have hail in the summer?

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Why Do We Have' - aaron-simpson


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

Why do we have the weather
WHY DO WE HAVE THE WEATHER ?

Just think about it!

  • Why is there wind? Why does it blow from one direction one day and another the next?

  • Why is it rainy one day and dry the next?

  • How come it’s cold in the winter?

  • How can we have hail in the summer?

  • What causes snow and freezing rain?


Let s take a look at why we have weather
Let’s take a look at why we have weather!


If we were to pick one term to help explain why we have weather, what do you think would be a good word?

You might pick heat or sun….but another good choice would be

Convection


Convection is the transfer of heat usually in gases or liquids
Convection is the transfer of heat, weather, what do you think would be a good word?usually in gases or liquids.


Air masses
Air masses weather, what do you think would be a good word?

  • Air masses have different temperatures

  • They also have different amounts of moisture

  • The source region is the area over which a particular air mass forms

  • It usually gives the air mass its characteristics: temperature and humidity!


Air mass modification
Air mass modification weather, what do you think would be a good word?

When an air mass travels over land or water that has characteristics different from those of its source region, the air mass can acquire some of the characteristics of that land or water and undergo modification.


After the atmosphere is warmed by radiation and conduction, the heat is transferred throughout the atmosphere by convection.

  • Since warmed air has more space between the molecules, it’s less dense and rises

  • Cooled air is more dense and tends to sink

  • In general, air near the equator tends to rise and air near the poles tends to sink


Take a look at this
Take a look at this! the heat is transferred throughout the atmosphere by convection.

Notice the band of clouds around the equator?

  • This is the ITCZ or intertropical convergence zone



Did you figure it out
Did you figure it out? equator?

  • Warm, moist air in the topics rises

  • Cold air can hold less moisture than warm air

  • As the moist air rises, it condenses and forms clouds!

    More on this later


Consequences of rotation the coriolis effect
Consequences of Rotation: equator?the Corioliseffect


The weather highways
The Weather Highways equator?

  • The rotation of the earth creates the Coriolis effect.

  • The Coriolis effect causes the air and water to be deflected to the right north of the equator.

  • This creates global weather highways


The westerlies
The Westerlies equator?

  • Because of our latitude, most of our weather comes from the west

  • Looking at the weather map, what type of weather might we expect?

  • What type of weather might we expect in a few days?


Let s break for a short review
Let’s break for a short review equator?

1.Transfer of heat in liquids or gases _____

2. _____ air is dense and tends to sink.

3. Band of clouds found around the equator ______

4. Cold air holds _____ moisture than warm air

5. The Coriolis effect causes the air and water to be deflected to the _____ if you are north of the equator


How did you do
How did you do? equator?

1.CONVECTION

2. COLD

3. ITCZ

4. LESS

5. RIGHT


Now what
Now What? equator?

  • Ok, so we know that the weather moves around on these highways and that warm air rises and cold air sinks.

  • But why is it sunny one day, and rainy the next?


Let s take another look at the weather map
Let’s take another look at the weather map equator?

  • Notice that there are H’sand L’s on the map

  • There are also blue lines with spikes and red lines with half circles

  • Let’s take a closer look!


High pressure areas
High Pressure Areas equator?

  • When cooler air sinks and is warmed, the air can hold more moisture

  • This usually means sunny skies

  • Winds tend to move clockwise around a high


Low pressure areas
Low Pressure Areas equator?

  • When warm air rises and is cooled, the air can not hold as much moisture

  • Often, these areas are associated with precipitation and stormy weather

  • Winds tend to move counter clockwise around the low


So if you see a big h on the weather map over the area you live you can expect fair weather
So, if you see a big equator?Hon the weather map over the area you live, you can expect fair weather


When you see a big l in your area there will probably be stormy weather
When you see a big equator?L in your area, there will probably be stormy weather


These highs and lows move more or less along the jet stream and bring us our weather changes
These highs and lows move equator?more or less along the jet stream and bring us our weather changes


Fronts and air masses
Fronts and Air Masses equator?

  • An air mass is a large body of air whose temperature and moisture are fairly similar at a given altitude

  • Fronts are boundaries separating different air masses

  • There are four different air masses that affect the United States


The air masses
The Air Masses equator?

  • cP( continental polar) : cold, dry stable

  • cT( continental tropical) : hot, dry, stable air aloft, unstable at the surface

  • mP( maritime polar) : cool, moist, unstable

  • mT( maritime tropical) : warm, moist, unstable



Ok now we see the difference in the air masses
Ok, now we see the difference in the air masses equator?

  • Let’s look at the different fronts and their impact on weather

  • Can you see the four different types of fronts on the map?


Warm fronts
Warm Fronts equator?

  • A warm front is warm air displacing cool air diagram

  • Shallow leading edge warm air must “overrun” cold air

  • These are usually slow moving


Cold fronts
Cold Fronts equator?

  • Cold air advances into region of warm air

  • Intensity of precipitation greater, but short lived

  • Clearing conditions after front passes

  • Usually approaches from W or NW


Stationary fronts
Stationary Fronts equator?

  • Surface positions of the front do not move

  • Often a region of clouds


Occluded fronts
Occluded Fronts equator?

  • Cold front overtakes warm front

  • Often found close to the low pressure center


Ready for a little quiz you ll need a sheet of paper
Ready for a little quiz? equator?You’ll need a sheet of paper

  • Write your answers as we go

  • Here we go!


1. equator?

  • Winds in a low pressure system move _____ around the low


2. equator?

  • What type of front can be found close to point D ?


3. equator?

  • Which of these fronts would you expect to have greater precipitation, but be short lived as the front passes?


4. equator?

  • Give the name of the air mass that would have the following characteristics:

  • cool, moist, unstable


5 that important weather word that refers to the transfer of heat
5. equator?That important weather word that refers to the transfer of heat


6 in general air near the equator tend to rise or fall
6. equator?In general, air near the equator tend to_____ ( rise or fall )


7. equator?

It causes air and water to be deflected to the right north of the equator


8 which of the weather highways usually controls our weather
8. equator?Which of the weather highways usuallycontrols our weather


9. equator?

Warm air holds ( more or less ) moisture than cold air


10. equator?

  • If there is a bigH on the weather map where you live, would you expect fair or stormy weather


How did you do1
How did you do? equator?

Let’s check the answers!


Answers
Answers equator?

1. Counterclockwise 8. Westerlies

2. Cold 9. More

3. Cold 10. Fair

4. Maritime polar (mP)

5. Convection

6. Rise

7. Coriolis


ad