Chapter 26

Weather and Atmosphere

Topics for Today

• Meteorology• Weather• Atmosphere

– Four Important Characteristics• Temperature• Composition• Pressure• Function

Meteorology• Meteorology

– A study of the entire atmosphere including its weather

• Meteorologist– The “weatherman” daily weather data and short-term weather forecasting

• Doppler Radar to predict precipitation, wind direction or storm tracks. • Interprets National Oceanic and Atmospheric Administration data• Publicizes National Weather Service alerts and warnings: storms, floods, fire threats

– Physical Meteorology: A study of the Physical and Chemical properties of the atmosphere

• Composition, pressure and movement • Energy content, transfer and balance• Factors affecting the formation of clouds, rain, and snow• Dispersal of air pollutants over urban areas• Phenomena such as the mechanics of thunderstorms and lightning

– Synoptic Meteorology: Weather Patterns• study large-scale (regional to global scale) weather systems using computers and sophisticated models

of atmospheric activity. • Global Winds, Jet Stream• Weather Patterns – El Nino• Very Large Storm systems like Hurricanes and Super cells

Weather

• Weather– Weather is the state of atmosphere at a given time and place

– Weather is a combination of… • current temperature • humidity • precipitation• cloudiness • visibility • wind• pressure

Thickness of the Atmosphere

Scale: atm/RE = Sheets/Ream (70mi / 4000mi = “x” / 500)

Patterns in…

• Temperature (26.3 pg 481)– Troposphere– Stratosphere– Mesosphere– Thermosphere

Patterns in…

• Composition– Homogeneous

• Troposphere to Mesosphere– Heterogeneous

• Upper Layers

Composition: Important GasesHomogeneous Lower

(mixed)• Troposphere

(diatomic gases)• N2 78%• O2 21%• Ar Less Than 1%• CO2 0.03%• Water Vapor 0 to 2%

• Stratosphere• N2 and O2

• Ozone (O3) layer (created when O2 absorbs UV)

• Mesosphere• N2 and O2

Heterogeneous Upper(layers by density)

• Thermosphere(monatomic gases)• O• N• He• H

• Exosphere• He layer• H layer

Mixed:Nitrogen

AndOxygen

Water Vapor, Argonand Carbon Dioxide

Layers By Mass:

O, N, He, H

Ozone: 2-8 parts per million

Patterns in…

• Density– 50% within 3 miles

• Pressure is 2x less

– 99.9% within 30 miles• Pressure is 1000x less

Pressure: Distribution of Mass

Pressure

Ideas about the “edge of the atmosphere” The Karman Line – air is too thin to support aeronautical flight. Air is so thin that aircraft have to fly so fast to obtain lift that they could leave orbit

Functions

1. Warm the Earth2. Protect the Earth

– Ozone Layer– Ionosphere

Function: Warms the Earth

Function: Ozone Layer

Function: Ionosphere

Function: Protects the Earth

The Atmosphere is a System with many Interacting Factors

http://wiki.ngscied.org/images/8/8a/Atmosphere-Detail.jpg

Summary

• Weather• Meteorology• Four Ways to Describe the Atmosphere

– Temperature– Composition– Pressure– Function