High energy galactic cosmic rays and bursts of solar energetic particles collide with gases in the atmosphere. The result is a complex mix of ionising radiation, the intensity and composition of which varies with position and time. Mathematical models of these phenomena are used to estimate the radiation exposure of aircrew and pilots, ensuring their exposures remain within acceptable limits.
The CARI-7 model was developed and is maintained by the US Federal Aviation Administration's Civil Aerospace Medical Institute. CARI-7 instantaneously calculates cosmic ray doses in the atmosphere. See here for a complete description of CARI-7.
The Route Dose API estimates radiation doses along a flight route between two airports with known ICAO or IATA codes assuming a great circle route, a constant altitude (in kilometers) and a user-defined flight duration (in hours). Dose rates are calculated using the CARI-7 model