Three major tundra climate zones exist. Alpine tundras are climate zones located on the tops of mountains. The Arctic tundra zone is the area located just beneath the Earth's northern ice cap region. The Antarctic tundra is located on the Antarctic peninsula.
Solar radiation, the electromagnetic radiation given off by the sun, is weakest at the polar regions of the Earth, so the Arctic and Antarctic tundras receive much less solar radiation than other areas of the world. It is affected by surface absorption ability, the time of year and cloud cover.
Dark surfaces absorb solar radiation better than light ones. The polar tundras are often covered with snow, so they do not absorb as much solar radiation as land regions. During the polar winter when the sun does not rise above the horizon, the tundra receives no solar radiation. During the polar summer, the sun is visible for most of the day, so the tundra receives more solar radiation. Cloud cover in the polar tundras helps warm the air by increasing the amount of longwave solar radiation that reaches the Earth's surface. Alpine tundra zones get greater solar radiation than polar tundra zones.
The temperature of the air in the tundra is a major factor on the overall climate. Temperatures in the polar tundras during the winter tend to be colder when the sky is clear and warmer when the sky is cloudy. In the summer, the opposite can be true. The average temperature range of the polar tundras is between -10 degrees Fahrenheit to 41 degrees Fahrenheit. Alpine tundra temperatures are affected by the altitude and latitude at which the alpine tundra is located. The average yearly temperature range for an alpine tundra zone is between -2 degrees Fahrenheit and 50 degrees Fahrenheit. Generally, the higher the altitude, the lower the air temperature. An alpine tundra in Alaska will occur at a much lower altitude than one closer to the equator because of its increased latitude.
All tundra regions are marked by low precipitation rates. Tundras are often described as frozen deserts. Most of the precipitation received in these zones comes in the form of snow. The plant life that adapts to the tundra also adapts to deal with these low levels of precipitation. Alpine tundras average approximately 9 inches of precipitation a year while polar tundras average approximately 8 inches yearly.
Low air pressure contributes to lower air temperatures. Alpine tundra areas are subject to the low air pressure that occurs at high altitude mountain tops. Polar tundra regions are affected by the almost constant low air pressure on the Earth's poles.
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