chapter 5 weather. what is weather? what makes weather change?

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Chapter 5 Weather

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Page 1: Chapter 5 Weather. What is weather? What makes weather change?

Chapter 5 Weather

Page 2: Chapter 5 Weather. What is weather? What makes weather change?

What is weather?

What makes weather change?

Page 3: Chapter 5 Weather. What is weather? What makes weather change?

Solar Radiation

• Temperature Changes with Latitude

Like equator Like at poles

Page 4: Chapter 5 Weather. What is weather? What makes weather change?

Seasonal Changes• Temperature Changes with Season

Page 5: Chapter 5 Weather. What is weather? What makes weather change?

The Atmosphere• Nitrogen 78%

• Oxygen 21%

• CO2 .038%

Carbon dioxideArgonWater vaporPollutantsHeliumEtc.

1%

Page 6: Chapter 5 Weather. What is weather? What makes weather change?

The Atmosphere

Page 7: Chapter 5 Weather. What is weather? What makes weather change?

Atmospheric Circulation

• Atmospheric Circulation

Circulation spawned by heating / cooling

Prevailing winds:

Generated by pressure differences and Coriolis effect

Page 8: Chapter 5 Weather. What is weather? What makes weather change?

Coriolis Effect

Southern Hemisphere

Page 9: Chapter 5 Weather. What is weather? What makes weather change?

Coriolis Effect

Page 10: Chapter 5 Weather. What is weather? What makes weather change?

• Size of deflection is directly related to both the speed at which the air is moving and its latitude.

• The Coriolis force is zero right at the equator.

• The Coriolis force only acts on large objects like air masses moving considerable distances. Small objects, for example ships at sea, are too small to experience significant deflections.

Gaspard de Coriolis (1792-1843)

Page 11: Chapter 5 Weather. What is weather? What makes weather change?

Trade Winds

Page 12: Chapter 5 Weather. What is weather? What makes weather change?

Horse Latitudes

30 degrees north(Horse latitudes)

&30 degrees south(Horse Latitudes)

&Equator(Doldrums)

Page 13: Chapter 5 Weather. What is weather? What makes weather change?

Fronts

What is a front?

Page 14: Chapter 5 Weather. What is weather? What makes weather change?

Fronts

Page 15: Chapter 5 Weather. What is weather? What makes weather change?

1. A front is defined by temperature, relative humidity, and air pressure:1. Temperature = the kinetic energy of a substance2. Relative Humidity = is a function of temperature and water content3. Air pressure = the weight of the atmosphere

Warm Fronts1. Retreating Cold fronts under advancing warm fronts are drawn out in a triangular fashion due to friction with the ground causing a triangular shape to the advancing warm front. 2. Warm fronts move towards the northeast3. Warm fronts usually travel at about 15mph

Cold Fronts1. Cold fronts become rounded due to friction with the ground as they advance on warm fronts.2. Cold fronts tend to move towards the east or southeast3. Cold fronts usually advance at speeds of 20mph4. Cold fronts may produce violent weather depending on their speed and air stability. 5. Faster moving cold fronts produce “squall Lines” Where high upper level winds stop a warm front from lifting up but whip up warm air ahead of the storm producing violent weather.

Fronts

Page 16: Chapter 5 Weather. What is weather? What makes weather change?

Pressure Systems (in the north)1. Low Pressure systems rotate counter clockwise2. High pressure systems rotate clockwise

Jet Streams1. Tend to follow the borders between warm and cold air2. In the summer they are located further north and in the winter further south3. Jet streams blow west to east in the northern and southern hemispheres4. How are airline flights impacted by jet streams (speed and turbulence)

Wind Shear1.Is any sudden change in wind speed or direction causing, turbulence.

Air Movement

Page 17: Chapter 5 Weather. What is weather? What makes weather change?

Turbulence

Page 18: Chapter 5 Weather. What is weather? What makes weather change?

Micro-Burst

Page 19: Chapter 5 Weather. What is weather? What makes weather change?

Micro-Burst

Page 20: Chapter 5 Weather. What is weather? What makes weather change?

Wind

What is wind and what makes wind?

Page 21: Chapter 5 Weather. What is weather? What makes weather change?

Beach WindsHanging at the beach

Day time Vs. Night time breezes

Page 22: Chapter 5 Weather. What is weather? What makes weather change?

Sea breezes

Page 23: Chapter 5 Weather. What is weather? What makes weather change?

Micro-Climate & Turbulence

Page 24: Chapter 5 Weather. What is weather? What makes weather change?

Wind

Page 25: Chapter 5 Weather. What is weather? What makes weather change?

Tornados

Page 26: Chapter 5 Weather. What is weather? What makes weather change?

Tornados

Page 27: Chapter 5 Weather. What is weather? What makes weather change?

Katabatic WindsKatabatic winds exist in many parts of the World and are winds that flow from the high elevations of mountains, plateaus, and hills down their slopes to the valleys or planes below. There are many diffent names for katabatic winds depending where they are located - Santa Anna (funneled & dry), and Chinook (dry).

Page 28: Chapter 5 Weather. What is weather? What makes weather change?

Chinook Winds Over Rockies

Page 29: Chapter 5 Weather. What is weather? What makes weather change?

Weather and Climate

• Rain shadows

Insert Fig 5.19 b

Page 30: Chapter 5 Weather. What is weather? What makes weather change?

Santa Ana Winds

Page 31: Chapter 5 Weather. What is weather? What makes weather change?
Page 32: Chapter 5 Weather. What is weather? What makes weather change?

NOR’EASTER

Page 33: Chapter 5 Weather. What is weather? What makes weather change?

1. A 10k foot mountain2. Air temperature at mountains base is 60 degrees3. Clouds form at 4k and extend to the mountain top4. What is the temperature of the valley floor (leeward side)5. How does humidity and temperature change from winward to leeward?

Problem 2A 14k peak with a valley temperature of 70Cloud formation begins at 7k and ends at 10k(5.5 and 3.2 = temperature changes for every thousand feet)

1. What is the temperature at 7K?2. What is the temperature at 10K?3. What is the temperature at 14K?4. What is the temperature in the leeward valley?

Is there compression of the air as in refrigeration or a decompression?

Adiabatic Problems

Page 34: Chapter 5 Weather. What is weather? What makes weather change?

Adiabatic heating and cooling is a temperature change within a gas due to compression (resulting in heating) and expansion (resulting in cooling); no heat is added to, or removed from the gas.

Why rising air cools and Rain Shadows

1. Decreased pressure

2. For every 1k/feet air rises it cools 5.5 farenheight due to lowering gas pressures and heats the same going down (adiabatic cooling & heating)

3. Air that rises and condenses at the same time only cools 3.2F for every 1k it rises due to the “heat of condensation”

4. Air moving up western slopes can come down warmer on the other side. Creating cool moist western slopes and warm dry eastern slopes.

Adiabatic Temperature Change & Condensation

Page 35: Chapter 5 Weather. What is weather? What makes weather change?

The Global Ocean• Patterns of Circulation in the Ocean

Influenced by:

1. Coriolis Effect 2. Winds

3. Land Masses 4. Water Density

Page 36: Chapter 5 Weather. What is weather? What makes weather change?

The Global Ocean

• Patterns of Circulation in the Ocean

Page 37: Chapter 5 Weather. What is weather? What makes weather change?

The Global Ocean

• Vertical Mixing of Ocean Water

Page 38: Chapter 5 Weather. What is weather? What makes weather change?

2005 Hurricane tracks

Page 39: Chapter 5 Weather. What is weather? What makes weather change?
Page 40: Chapter 5 Weather. What is weather? What makes weather change?

Hurricanes• Severe weather events:• Tropical cyclones• Atlantic Ocean = hurricanes• Pacific Ocean = typhoons• Indian Ocean = cyclones

Category One Hurricane: Winds 74-95 mph Category Two Hurricane: Winds 96-110 mph - Storm surge generally 6-8 feet above normalCategory Three Hurricane: Winds 111-130 mph - Some structural damage to small residencesCategory Four Hurricane: Winds 131-155 mph - Complete destruction of mobile homesCategory Five Hurricane: Winds greater than 155 mph - Storm surge generally greater than 18 ft above normal and framed homes destroyed

Page 41: Chapter 5 Weather. What is weather? What makes weather change?

Hurricanes1. Hurricanes are powered by the energy released during condensation

2. Hurricanes are steered by prevailing wind patterns and wind sheer will destroy a hurricane.

3. What are positive and what are negative feed-back-loops for hurricanes

4. When winds reach 74mph a tropical storm becomes a hurricane

5. Why is the eye clear? Air coming in from the eye wall is coming inward towards the center from all directions. This convergence causes the air to sink in the eye. This sinking creates a warmer environment and the clouds evaporate leaving a clear area in the center.

Page 42: Chapter 5 Weather. What is weather? What makes weather change?

Katrina

Page 43: Chapter 5 Weather. What is weather? What makes weather change?

Katrina

Page 44: Chapter 5 Weather. What is weather? What makes weather change?

El Niño/Southern Oscillation (ENSO)

• Chicken and Egg scenario – ocean temperatures or trade winds?

This decreases during El Niño

Increases during La Niña

http://esminfo.prenhall.com/science/geoanimations/animations/26_NinoNina.html

Page 45: Chapter 5 Weather. What is weather? What makes weather change?

El Niño/Southern Oscillation (ENSO)

1. Heavier rainfall over coastal equatorial South America

2. Drought in Western Pacific (Indonesia & Australia)

3. Increased transmission of disease – mosquitoes and stagnant water – Les or More water and heat

4. Migration of fish species (North or South – Inshore or Out)

5. Death of seals and sea birds due to changing fisheries

6. Heavier rains in the southwestern deserts of United States

7. Fewer hurricanes in the Atlantic

8. Changes in disease due to shifts in temperature and moisture

2010-2011 Australia has record flooding?• La Nina or El Nino• Weak or Strong

Page 46: Chapter 5 Weather. What is weather? What makes weather change?

El N

ino

La N

ina

Page 47: Chapter 5 Weather. What is weather? What makes weather change?

Lightning

What do you know about lightning

Page 48: Chapter 5 Weather. What is weather? What makes weather change?

Lightning

Thunder and Lightning

1. Sound travels about one mile every 5 secondsSo if you count to ten the storm is 2 miles away

2. Thunder rumbles because the sound from different points on the bolt reaches our ears at different times

3. Thunder, is produced by the heating (expansion) and cooling (contraction) of the air around a lightning strike.

4. Lightning forms from negative charges at the bottom of the cloud that meet with positive charges from the ground. A stepped leader from the cloud meets a streamer from the ground. Visible light moves up and charge flows down. Individual charges are drained separately causing lightening to flash and strike multiple times in one location.