The Lower Atmosphere refers to the part of the Earth's atmosphere that is closest to the surface. This layer includes the troposphere, where we experience weather, clouds, and air we breathe. It extends from the ground up to about 8 to 15 kilometers (5 to 9 miles) high, depending on where you are on Earth. In the lower atmosphere, temperature decreases with altitude, which is why mountains can be colder than valleys. This layer is crucial for life, as it contains the necessary gases like oxygen and nitrogen. It also plays a vital role in the water cycle, helping to distribute moisture around the planet.