Anti-radiation missile as the longer the radar is off (and assuming it never turns back on), the more error is introduced into the missile's course. The ALARM even has an added loiter mode, with a built in parachute, enabling it to descend slowly until the radar lights up, when the rocket motor will re-ignite. Even a temporary shut down of the enemy's missile guidance radar can be of a great advantage to friendly aircraft during battle. The DRDO Anti-Radiation Missile is under development by India. The MAR-1 is under development by Brazil. Several surface-to-surface missiles, like the P-700 Granit, P-500 Bazalt, MM40
Speed of sound km) can produce refraction equal to a typical temperature lapse rate of . Higher values of wind gradient will refract sound downward toward the surface in the downwind direction, eliminating the acoustic shadow on the downwind side. This will increase the audibility of sounds downwind. This downwind refraction effect occurs because there is a wind gradient; the sound is not being carried along by the wind. For sound propagation, the exponential variation of wind speed with height can be defined as follows: where In the 1862 American Civil War Battle of Iuka, an acoustic shadow, believed to have been enhanced