1 Atmospheric Structure and Energy Free Online FlashCards

Which two gases make up most of dry air?

Dry air near Earth’s surface is about 78% nitrogen and 21% oxygen.

How does water vapor differ from the main gases in air?

Water vapor varies greatly with place and time, from nearly zero in very dry air to several percent in warm, humid air. It is essential to clouds and precipitation.

Why do pressure and density generally decrease with altitude?

Gravity pulls most air molecules toward Earth’s surface, so atmospheric pressure and density generally decrease with height.

What are key characteristics of the troposphere?

The troposphere contains most atmospheric mass, nearly all weather, and nearly all atmospheric water vapor. Temperature usually decreases with height in this layer.

Where is the ozone layer, and what does it absorb?

The ozone layer is in the stratosphere, where it absorbs much of the Sun’s harmful ultraviolet radiation.

How do incoming solar radiation and surface emission differ?

Solar energy arrives mainly as shortwave radiation. Earth’s warmed surface emits energy mainly as longwave infrared radiation.

How do greenhouse gases affect Earth’s outgoing infrared energy?

Greenhouse gases and clouds absorb and emit some infrared radiation from Earth’s surface, affecting how quickly heat escapes to space.

How can uneven heating produce a sea breeze?

Uneven heating creates temperature and pressure differences that help set air in motion. On a sunny day, land may warm faster than nearby water, drawing cooler air inland as a sea breeze.

What is radiation as a method of heat transfer?

Radiation transfers energy by electromagnetic waves and can travel through space; sunlight warms Earth without air carrying the energy.

How does conduction warm air near the ground?

Conduction transfers heat through direct contact. The ground can warm the thin layer of air touching it, although air is a poor conductor.

How does convection move heat through the atmosphere?

Convection transfers heat through fluid movement. Surface-warmed air becomes less dense and can rise, while cooler, denser air moves in to replace it.

What processes together make up evapotranspiration?

Evapotranspiration is the combined transfer of water vapor to the atmosphere through evaporation from surfaces and transpiration from plants.