Cloudiness Variation Observed at Yangbajing During Forbush Decrease of Galactic Cosmic Rays

Abstract：

Due to the solar modulation and other factors, the cosmic ray flux has some changes which maybe induce variation of the Earth's climate, such as cloudiness. It is possibly an effective way to research connection between cosmic ray and cloud through studying effect on cloudiness of galactic cosmic ray flux associated with Forbush decrease (FD) events, because climate variation, especially cloudiness, has a response to the FD events.Three FD events had been recorded with Yangbajing neutron monitor during the years from 2003---2004. Variation of cloudiness following FD over the regions of Yangbajing cosmic ray observation has also been observed by infrared radiometer. By statistically analyzing the FD events, it has been found that significant increase of cloud takes place during FD events. The results indicate that the cloudiness increases at lower latitudes in the regions of thinner cloud, which is consistent with results at this lower latitudes found by other investigators.