Redefinition of the meteor storm from the point of view of spaceflight security Original Research Article

ZHR∗ is defined as number of meteoroids passing 1000 km2 zenith area per hour which can produce craters no less than 1 cm in diameter on an aluminum material. The relationship between ZHR and ZHR∗ is deduced. We evaluate the strong meteor showers since 1990s by ZHR∗ instead of ZHR and find the Giacobinid (Draconid) shower in 1998 is much stronger than the Leonid shower in 1999, 2001 and 2002.