Solar radiation from the sun controls weather on earth in a variety of ways. Solar radiation, for example, provides 100% of earth's energy budget. This energy given by the sun then is absorbed and heats the planet, or is reflected back into space. A surface's absorption depends on how well it does the first, its albedo on how well it does the second. Some examples of surfaces with a high absorption rate are asphalt, concrete, and other dark, dry materials, which causes a heat island effect in large cities made primarily of those surfaces wherein more heat than usual is absorbed and the areas are especially hot compared to greener places nearby.
When the sun heats the earth, however, it does so unevenly, causing pockets of
warm and cool air. Because warm air rises and cool air sinks, this
creates uneven pressure within the atmosphere. Wind is the horizontal
travel of air from high pressure areas into low pressure areas, as the
atmosphere attempts to even out its own pressure.
The earth's temperature is also affected by greenhouse gases. Though the earth's atmosphere is made of about 78% Nitrogen and 21% Oxygen, the last 1% contains gases like water vapor, carbon dioxide, methane, and more. These gases trap reemitted solar radiation into the atmosphere and prevent it from returning to space, warming the earth. Levels of some of these gases within the atmosphere has been on the rise in recent years, caused mostly by the burning of fossil fuels in human society.
Another important factor in atmospheric behavior is the prevalence of aerosols in the atmosphere. Aerosols are small solid or liquid particles suspended in a gas, and they can block solar radiation from either entering or leaving earth's atmosphere. They are caused by many processes and events, both human and natural, and can be important or extremely damaging. Some examples of the less pleasant, polluting ones would be sulfur, nitrogen oxides, and hydrocarbons. Clouds are also aerosols.
There are three main groups of clouds: Cirro, or high altitude, Alto, or middle altitude, and nimbus, low altitude clouds carrying precipitation. These main types are further divided into cumulus, or puffy, stratus, or layered, and cirrus, or wispy clouds.
Humidity is a related concept to aerosols, referring to the amount of
water molecules in the air. Air can hold different amounts of water
molecules at different temperatures, however, so humidity is usually
measured as a percentage of the air's water content versus the air's
possible water content, with 100% being completely saturated.
Yet another thing which affects earth's climate is the gravity which creates our atmosphere by pushing air molecules toward the earth, effectively pressurizing the atmosphere. This pressure is defined as the force air exerts over an area. Air density, a related concept, deals with the amount of air molecules in a given space.This density decreases rapidly as one travels higher into the atmosphere. Air temperature decreases similarly, with the rate of decrease being called the lapse rate. Earth's atmosphere is divided into several sections based on trends in temperature for each layer. These are, in order from the bottom up, the troposphere, the stratosphere, the mesosphere, the thermosphere, and the exosphere.
