Understanding Solar Radiation and Climate Factors

Fate of incoming solar radiation

Scattered - small dust particles and gas molecules in the atmosphere scatter some of this energy in all directions.

Fate of incoming solar radiation

Reflection - light bounces back from an object at the same angle at which it encounters a surface and with the same intensity.

Fate of incoming solar radiation

Albedo = fraction of total radiation that is reflected by a surface.

Fate of incoming solar radiation

Absorption - gases are selective absorbers.

Fate of incoming solar radiation

N2 poor absorber.

Fate of incoming solar radiation

O2 and O3 efficient absorbers of UV.

Fate of incoming solar radiation

Water vapor efficient absorber of infrared.

Fate of incoming solar radiation

None of the Atm. gases are effective absorbers of visible radiation.

Fate of incoming solar radiation

Greenhouse effect.

Why temperatures vary

Differences in receipt of solar radiation - Latitude.

Why temperatures vary

Differences in receipt of solar radiation - Season.

Why temperatures vary

Differences in receipt of solar radiation - Time of day.

Why temperatures vary

Differences in characteristics of Earth's surfaces - Different surfaces absorb varying amounts of solar energy.

Why temperatures vary

Land heats more rapidly and to higher temperatures than water, and it cools more rapidly and to lower temperatures than water.

Why temperatures vary

Altitude - temperatures drop with altitude in the troposphere.

Why temperatures vary

Prevailing winds - coastal locations where prevailing winds blow from the ocean onto the shore experience considerably different temperatures than does a coastal location where the prevailing winds blow from the land toward the ocean.

Why temperatures vary

Windward coast - moderating influence of ocean - cool summer and mild winters.

Why temperatures vary

Leeward coast - warmer summers and colder winters.

Why temperatures vary

Cloud cover and albedo - Clouds reflect heat.

Why temperatures vary

Snow and albedo - one reason mountain glaciers do not melt away in the summer.

Water changes of state

Water is a polar molecule.

Water changes of state

Water is the only substance that naturally exists on Earth as a solid (ice), liquid, and gas (water vapour).

Water changes of state

Ice - molecules are not free to move relative to each other.

Water changes of state

Liquid state - molecules are still tightly packed but are moving fast enough that they slide past one another.

Water changes of state

Vapour - molecules acquire enough energy to break the remaining molecular attractions.

Water changes of state

Condensation - Gas to liquid.

Water changes of state

Evaporation - Liquid to gas.

Water changes of state

Deposition - Gas to solid.

Water changes of state

Sublimation - Solid to gas.

Humidity

Humidity is the amount of water vapour in air.

Humidity

Saturation of air with water vapour depends on temperature.

Humidity

Relative humidity - our body's main source of cooling is evaporation of perspiration.

Humidity

Dew point - temperature at which a parcel of air reaches saturation.

Adiabatic temperature changes

Condensation level - Level where air parcel rises high enough that it cools to its dew point, triggering condensation.

Processes that lift air

Orographic lifting - occurs when air is forced to rise over a mountainous barrier.

Processes that lift air

Frontal lifting, in which warmer, less-dense air is forced over cooler, denser air.

Processes that lift air

Convergence, which is a pileup of horizontal airflow that results in upward movement.

Processes that lift air

Localized convective lifting, in which unequal surface heating causes localized pockets of air to rise because of their buoyancy.

Clouds

Cloud condensation nuclei, serve as surfaces for water-vapor condensation.

Clouds

Clouds are classified based on how they appear when viewed from Earth's surface.

Fog

Fog is defined as a cloud with its base at or very near the ground.

Precipitation

Precipitation - water that falls towards the ground.

Wind

Wind - result of horizontal differences in air pressure.

Wind

Wind is controlled by a combination of three factors: pressure gradient force, Coriolis effect, and friction.

Wind

Isobars - lines connecting places of equal air pressure.

Wind

Spacing of isobars indicates the amount of pressure change occurring over a given distance.

Coriolis effect

Circulating air is deflected toward the right in the Northern Hemisphere and toward the left in the Southern Hemisphere.

Human impact on climate

Human impact on global climate.