Forbush decreases registered onboard aircraft

Forbush decreases have been registered onboard aircraft; an important dropdown of the aircraft crew exposure was stated. Particularly important effect of that kind was registered during the period of disturbed solar conditions at the end of October 2003, it was, however, already registered during 2001 year. The onboard dosimetry and geophysical data are presented and compared. Comparable decrease is observed for onboard measurements and geographically nearby cosmic ray neutron monitor's data. Some previous data obtained during 2001 year also in the case of a solar flare are also presented. It seems that both quantitative and qualitative changes of cosmic rays regime accompany variations such as solar cosmic ray events and Forbush decreases. These changes can be characterized on the base of onboard aircraft dosimetry measurements with a properly chosen instrument.