Correlation of Ground‐ and Space‐based Bolidesa

Abstract

ABSTRACT: Data on large meteoroid impacts into the Earth's atmosphere are available up to over ten meter sizes from global satellite observations by optical sensors, while data from ground‐based photographic observations of meteoric fireballs (bolides) are available only up to meter sizes. However, the ground‐based observations yield very precise data on the motion and ablation of these bodies, as well as their light curves. The space‐based observations yield very precise light curves. Using data of the brightest Prairie Network bolides, ablation coefficients are determined for 48 bolides brighter than magnitude −10 and compared to relative time changes of their brightness. This way the known classification scheme for photographic bolides (based mostly on observed ablation coefficient) is related to maximum increase and decrease of their brightness. The same classification scheme is applied to 16 light curves of somewhat larger bodies observed globally by DOD satellites. Size range of these bodies is found to be from 2 to 15 m with median value of 3 to 4 m. Only separation of type I + II (38%) from type IIIA + IIIB (62%) is possible. Increase of relative strength of populations of cometary meteoroids (namely of the IIIB type) observed for photographic meteors up to a size of 5 m continues to larger sizes up to 15 m. Majority of meteoroids in the size range from 2 to 15 m are cometary bodies with the weakest known structure.