Albedo their reflectivities. Fresh 'black' ice exhibits Fresnel reflection. Snow on top of this sea ice increases the albedo to 0.9. Cloud albedo has substantial influence over atmospheric temperatures. Different types of clouds exhibit different reflectivity, theoretically ranging in albedo from a minimum of near 0 to a maximum approaching 0.8. "On any given day, about half of Earth is covered by clouds, which reflect more sunlight than land and water. Clouds keep Earth cool by reflecting sunlight, but they can also serve as blankets to trap warmth." Albedo and climate in some areas are affected by artificial clouds, such as
Surface-to-surface missile Surface-to-surface missile A surface-to-surface missile (SSM) or ground-to-ground missile (GGM) is a missile designed to be launched from the ground or the sea and strike targets on land or at sea. They may be fired from hand-held or vehicle mounted devices, from fixed installations, or from a ship. They are often powered by a rocket engine or sometimes fired by an explosive charge, since the launching platform is typically stationary or moving slowly. They usually have fins and/or wings for lift and stability, although hyper-velocity or short-ranged missiles may use body lift or fly a ballistic trajectory. The V-1 flying