Background Information: Different Climates
The earth's climate varies from place to place. Locations near the Equator tend to be constantly hot and wet, such as the Pacific islands and the Amazon Basins. Some places near the North and South Poles, such as Antarctica and Greenland, are extremely cold and dry.
Amount of Solar Radiation
The main cause of the variation of temperature is the amount of solar energy that is received (Module One, Seasons). In general, in higher latitudes further away from the Equator, less solar radiation is received and the lower the temperature experienced.
On a global scale, the amount of energy received from the Sun is much greater in the Southern Hemisphere during December and January each year and much less during June and July. In the Northern Hemisphere, radiation is greater during June and July and less during December and January.
Altitude
The altitude (height) of a place also affects the temperature. As shown already in Module One, the ground receives solar radiation and then heats the air above it by long-wave radiation, conduction, and convection. So the closer to the earth's surface, the warmer the temperature of the air. The temperature decreases with height in the troposphere at a rate of 6.5 degrees for every 1000 meters. This is why glaciers can be found in Papua New Guinea, although it is very close to the Equator.
Distance from the Sea
The distance from the sea affects the temperature. Land has a lower specific heat capacity (i.e., amount of heat energy required to raise the temperature of a unit mass by 1 degrees Celsius) than water; it heats up more quickly during the day than the sea and loses its heat more quickly at night. During the summer season, the interior of a large island or land mass becomes much hotter than coastal areas, which are kept cooler by the sea. During the winter season, areas that are inland get cooler than those close to the sea during the day and vice versa at night. Because most Pacific islands are very small, the temperatures during summer (December and January) are not as hot as those in the middle of Australia, which is further south but a long way from the sea.
Cloud Cover
Cloud cover affects temperature (slightly more detail of clouds is explained in the following section of this module). Thick clouds reflect incoming solar radiation by day and also prevents much of the long-wave ground radiation by night from leaving the lower layers of the troposphere. So, cloudy conditions cause lower temperatures by day and higher temperatures by night.
Type of Ground Surface
The type of surface also affects the temperature. Areas that are covered in ice and snow reflect almost all of the incoming solar radiation and cannot benefit to the same degree as darker surfaces. Sandy beaches may reflect up to half of all the solar energy received, particularly if they are composed of white sand. In contrast, dark surfaces such as forests will absorb most of the incoming radiation, and temperatures above them will be higher than over light-colored surfaces. As one may be aware, this makes white cars more heat tolerant.
