WINDS

Weather and Climate Day 6

Objectives

• Today I will be able to analyze winds by:– Explaining how wind is _____________– Examine ____________wind patterns– Examine ____________wind patterns

Key Points• The ultimate energy source for most wind is solar radiation.• Pressure differences generate winds.• A steep gradient produces strong winds.• The Coriolis effect affects wind direction.• High-pressure systems are usually associated with

descending air, clear weather, and relatively dry conditions.• The general movement of low-pressure centers across the

United States is from west to east.• A sea breeze usually originates in the day and flows toward

land.• La Nina is associated with surface temperatures in the

eastern Pacific that are COLDER than average (this year)

Air-Pressure DemonstrationWatch the demonstration of gradients creating speed. Answer the

following questions on your warm up:

Pre-Demo:1. Which ramp setup do you think will cause the ball to roll the

fastest?Post-Demo:2. Were you right? Which ramp set up caused it to move the

fastest?

• Like the ramps, air pressure also forms gradients. Wind is air that flows down the “slopes” of air pressure gradients.

3. What air pressure conditions do you think would favor faster wind speeds? Steep or shallow gradients?

Wind• _____________________is the ultimate

energy source for most wind. • The sun’s rays heat the earth unevenly,

creating pressure differences in the air around us.

• ____________________________________ ____________________________________– Air flows from areas of higher pressure to areas

of lower pressure. – Air is always trying get to a place with lower

pressure.

Wind• Three factors combine to control wind:

______________________________________ ______________________________________.

1. Friction• Friction acts to ___________air movement,

which changes wind direction.

Winds

2. The Coriolis Effect• The Coriolis effect _______________________. Remember the Coriolis effect from oceans?

How does it affect ocean currents in the Northern Hemisphere?

It deflects them in different ___________for each Hemisphere.

• In that same way, it affects wind ____________!

Winds

• The Coriolis Effect and how it changes wind DIRECTION

Winds

3. Pressure gradient: – the amount of ________________occurring over

a given ______________________.• Pressure gradients _____________________

• Remember the ramp? When would be have stronger wind with a steep or gentle gradient?• ______________________________________

_____________________________________.

Pressure Centers and WindsWeather Forecasting• Knowing that air pressure causes winds, how could

that help meteorologists predict global weather patterns?

• Scientists study pressure differences and use data to ____________where wind is taking weather!

• If scientists measure decreased pressure in Henderson, how could that affect the weather?

____________would be ________________, and it could carry a _______________.

Pressure Centers and Winds

Weather and Air Pressure• _______pressure - Produces rising air in association with

cloud formation and ________________. STORMY

• High pressure – Produces sinking air causing _________ __________________, and dry conditions.

• What type of weather would you expect when there is a high pressure system?

• High-pressure systems are usually associated with __________________________________________________________________________________________.

Pressure Centers and Winds

Global Wind Patterns• Because of differences in temperatures:– ______________from the equator and moves

towards the poles– _______________at the poles and moves towards

the equator• Because our earth ROTATES wind patterns are

broken up into ___________main winds:1. Trade winds2. Westerlies3. Polar Easterlies

Pressure Centers and Winds

1. ________________are a surface wind that blows between the subtropical high and the equator.

2. ________________are the dominant west-to-east motion of the mid-latitudes.

3. _________________________are winds that blow from the polar high downward from east to west. These winds are not constant like the trade winds.

The United States is most effected by Westerlies.

• Because of the Westerlies, the general movement of low-pressure centers across the United States moves from ______________ to _____________.

Regional Wind Patterns

• Not all winds fall into the general patterns of Global Winds. They can be determined on a more “regional” scale, affecting a _________________.

1. Land and Sea Breezes• A sea breeze usually ____________________

_____________________________________.• At ____________, the wind will come from the

land and blow _____________the ________.

Regional Wind Patterns• Land and Sea Breezes

Remember from our OCEANS unit – WIND is one of the first things you notice when you go to the beach!If you stand facing the water at 8:00 pm would the wind hit you in the face or in the back?What about at 10:00 am?

Regional Wind Patterns

2. Valley and Mountain Breezes• In the day, the air on the mountains is ________

more intensely than air on the valley floor.

• Because this warmer air on the mountain slopes is ___________________, it glides up along the slope and generates a valley ____________________.

• After sunset the pattern is reversed. It is warmer on the valley floor and wind glides down.

Regional Wind Patterns• Valley and Mountain Breezes

El Niño • In recent years, our planet has had some severe

weather that has been contributed to el Niño or la Niña.

• El Niño:– This happens when the Pacific Ocean is __________

more than usual.– This disrupts weather patterns globally causing

__________________weather patterns.– This is what happened last year and is the reason we got

so much snow here.• THINK: What sort of effect could El Niño have on

oceans? How could this impact humans?

La Niña

• La Niña– This weather condition is the opposite of el Niño:– La Niña occurs when the surface temperature in

the Eastern Pacific are _____________than average.

– This also causes extreme weather patterns.

– This year we are experiencing La Niña – what are some weather conditions that you’ve heard about on the news that might be caused by la Niña?

Check In – Use Complete Sentences1. What is the ultimate energy source for most wind?2. Which FORCE generates winds?3. A STEEP pressure gradient produces which type of winds?4. What part of the wind does the CORIOLIS EFFECT

influence?5. What type of weather is associated with HIGH Pressure

systems? What about with LOW?6. Low Pressure centers move across the US from

___________ to _____________ direction.7. Explain the pattern of sea breezes.8. Which phenomenon is associated with surface

temperatures in the eastern Pacific that are colder than average?

Study Guide Work Time

• Your study guide will be due on THURSDAY for a QUIZ grade.

• Use this time wisely to work on the first 22 questions.

• My data shows that students who complete the study guide and turn it in on time have 80% average on their tests! Make this count!