air weather and climate

Air Weather and Climate

Chapter 17

APES March 2009

What do you know about weather?

Weather vs. Climate

What is weather?

The current weather conditions

(temperature, precipitation, winds, pressure)

What is climate?

Long term weather patterns for an area

Composition and Structure of the Atmosphere

• What is it made of?

• What does it look like?

• How do we organize it?

History of the air

We are unique as a planet: we have an atmosphere!

What does that do for us?

Have we always had an atmosphere?

How did we get one?

H and HE

C, N, O, S, and others added by volcanoes

Free O2 and water vapor due to PLANTS

Delicate balance: carbon levels

Composition of air

Air Pressure

• What causes air pressure?

Pressure is measured in mb

Pressure

Sea level: 1000mb (14.5 lbs/square inch)

8,850 feet

Above sea level: 500 mb

12,500 feet

Above sea level: 0 mb

Layers of the Atmosphere

The layers

• Take notes on the characteristics of the layers on pages 371-372

WEATHER

Driven by the sun

Global cycling of air

Creates our climate

Distributes energy and material around the world!

Electromagnetic spectrum

Solar Radiation

Why is it not the same all over?

Greenhouse effect is natural.

WE are making it stronger….

Cyclonic Storms

• Hurricanes

Cyclonic Storms

Tornadoes

CLIMATE

Patterns of weather over time.

Why do Climates Change?

The Milankovitch Theory

Periodic shifts in the Earth’s orbit and tilt result in global climate change.

Evidence

El Nino

El Nino/La NinaThe El Nino Southern Oscillation

Every three to 5 years, El Nino occurs.

In between years are called El Nina.

El Nino: Indonesian Low collapses and warm surface water surges across the Pacific.

Several theories why: trade winds shifting, ocean currents changing…..

La Nina

La Nina

La Nina

La Nina effects us!

Why study this?

There is evidence these natural cycles are being disrupted/exacerbated by global climate change.

Know how these changes affect us.

Pacific Decadal Oscillation (PDO)

• The change in location of the cold and warm water masses alters the path of the jet stream.  Put simply, the jet stream in the northern hemisphere delivers storms across the United States.  The PDO phase that we appear to have entered will act to steer the jet stream

further north over the Western United States.

Human-Caused Global Change?

WHY?

Green house gas emissions

Energy Consumption

BBC SITE

Greenhouse Gases

• Carbon dioxide (absorbs IR radiation and warms surface air)

Human Activities that release this gas:Burning fossil fuels, making cement, burning

biomass

How is it taken up by nature?Terrestrial ecosystems, absorbed by oceans

Greenhouse GasesOther gases include:Methane (released by rice patties, coal mines, ruminant animals, landfills,

pipeline leaks)

Chlorofluorocarbons(regulated in our country, but still a problem)

Nitrous oxide(Burning organic material and dentrification)

Sulfur hexafluoride(electrical insulation, magnesium production, and medical inhalers)

Effects of Climate Change

Effects

IS it happening?

Photographer site

Regional change

Hot spots

UCSCool fingerprints