Answer
The Earth's atmosphere is divided into four distinct layers based on how temperature changes with increasing altitude.
The first layer, closest to the Earth's surface, is the troposphere. In the troposphere, temperatures generally decrease with increasing altitude, a phenomenon known as the lapse rate. On average, the temperature decreases at a rate of about 6.5 degrees Celsius per kilometer of ascent.
The second layer is the stratosphere, which lies above the troposphere and extends up to around 50 kilometers (31 miles) above the Earth's surface. Unlike the troposphere, the stratosphere experiences an increase in temperature with altitude. This temperature rise is primarily due to the absorption of ultraviolet (UV) radiation by ozone molecules, creating the "ozone layer" that plays a vital role in protecting life on Earth by filtering out harmful UV radiation.
Beyond the stratosphere lies the mesosphere, stretching up to about 85 kilometers (53 miles) in altitude. In this layer, temperatures begin to decrease again with increasing altitude.
The thermosphere is the uppermost layer, extending beyond the mesosphere to about 500 kilometers (311 miles) above the Earth's surface. In the thermosphere, temperatures rise with altitude due to the absorption of extreme ultraviolet (EUV) and X-ray radiation from the Sun. The transitions from one layer to another are characterized by sharp temperature changes known as the tropopause, stratopause, and mesopause, respectively.
Work Step by Step
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