HNRS: Broadcast Meteorology - Chapter 1

Variable gases

Gases whose concentration changes by location and time

Permanent gases

Gases with nearly constant atmospheric concentrations

Tropospheric temperature decrease

Air cools with height because it expands as pressure drops

Tropopause height in warm regions

Warm air expands upward raising the tropopause

Pressure with altitude

Air pressure decreases as height increases

Seasonal radiation change

Earth tilt alters sun angle and daylight length

Subsolar point

Location where the Sun is directly overhead

Subsolar point importance

It receives the most intense solar radiation

Conduction

Heat transfer through direct contact

Conduction depends on

Material type and temperature difference

Stefan Boltzmann Law

Hotter objects emit more total radiation

Wiens Law

Hotter objects emit radiation at shorter wavelengths

Kirchhoffs Law

Good absorbers are good emitters

Temperature and radiation

Higher temperature increases radiation and shortens wavelength

Thermal radiation rate

Radiation increases rapidly as temperature rises

Aerosols

Small particles suspended in the atmosphere

Aerosol effect on radiation

Aerosols scatter absorb and reflect sunlight

Scattering

Redirection of radiation by particles

Blue sky explanation

Blue light is scattered more than red light

Rayleigh scattering

Scattering by very small particles

Mie scattering

Scattering by larger particles

Particle size and scattering

Smaller particles scatter shorter wavelengths

Sun angle effect

Higher sun angles concentrate energy

Albedo

Fraction of sunlight reflected by a surface

Albedo in visible light

Surfaces reflect different wavelengths differently

Measuring albedo

Compare incoming and reflected radiation

High albedo surface

Snow or ice reflects most sunlight

Low albedo surface

Asphalt or forests absorb most sunlight

Skin color and albedo

Darker skin absorbs more sunlight

High latitude seasonal range

Higher latitudes have larger sun angle changes

Ocean proximity effect

Water moderates air temperature

Maritime temperature range

Water reduces annual temperature variation

Other temperature controls

Elevation clouds currents winds and land cover