Ground-based observations refer to scientific observations made from the surface of the Earth, as opposed to observations made from space or aircraft. Researchers use ground-based observations to study a wide range of phenomena, including weather patterns, atmospheric conditions, astronomical events, and environmental changes. These observations can be made using instruments such as telescopes, radars, weather stations, or monitoring devices, and can provide valuable data for understanding and predicting various natural processes. Ground-based observations are important for studying the Earth and its surroundings, and are often used in conjunction with other types of observations to provide a comprehensive understanding of the world around us.