Learning Module 2.1
Interaction of EMR with Earth's Atmosphere and Surfaces
The Sun is the Earth's primary source of electromagnetic radiation (EMR). In the previous section, we learned that the Sun radiates electromagnetic energy over a wide range of wavelengths and emits the most radiation in the visible portion of the spectrum. Before the electromagnetic energy from the Sun reaches the Earth’s surface, it must pass through the atmosphere. As the energy passes through the atmosphere, it interacts with the molecules and particles present in the atmosphere. In the atmosphere, EMR is scattered, absorbed and a portion of the energy passes through the atmosphere to reach the Earth's surface. Once it reaches the Earth's surface this energy can be reflected, absorbed or transmitted. In this section we will learn about how the atmosphere and the surfaces on the Earth interact with EMR and how this is fundamental to remote sensing.