Solar Radiation Alert System

Copeland K, Sauer HH, Friedberg W

FAA Office of Aerospace Medicine - Civil Aerospace Medical Institute

关键词: Solar Radiation;    Monte Carlo Particle Transport Code;    Solar Protons;    Solar Particles;    Space Weather;    Solar Flare;    Coronal Mass Ejection;   

RP-ID  :  DOT/FAA/AM-05/14

美国|英语

来源: Federal Aviation Administration

【 摘 要 】

A solar radiation alert (SRA) system has been developed to continuously evaluate measurements of high-energy protons made by instruments on Geosynchronous Operational Environmental satellites. If the measurements indicate the likelihood of a substantial elevation of effective dose rates at aircraft flight altitudes, the Civil Aerospace Medical Institute issues an SRA to the aviation community via the National Oceanic and Atmospheric Administration Weather Wire Service.This report describes the methodology of the SRA system. A Monte Carlo particle transport code was used to estimate the fluences of secondary particles (protons, neutrons, pions, kaons, photons, electrons, and muons) in selected energy ranges at specific altitudes. Coefficients to convert particle fluence to effective dose incorporate radiation-weighting factors and tissue-weighting factors recommended by the International Commission on Radiological Protection, except that the radiation-weighting factor for protons was changed from five to two, as recommended by the National Council on Radiation Protection and Measurements.Effective dose rates from solar-proton-induced ionizing radiation in the earth's atmosphere at high geomagnetic latitudes were calculated for the solar proton event of 20 January 2005. The event started at 06:50 Universal Time, and within 5 minutes, dose rates at 60,000, 40,000, and 30,000 ft (relative to mean sea level) reached maximum values of: 140, 55, and 21 microsieverts per hour, respectively.