THE CHARACTERISTICS OF COSMIC RAY INTENSITY ON 4-17 AUGUST 1989

The cosmic ray Forbush Decreases(FDs) are frequently related to the solar flares. Statistically, only the bright flares of importance 3 and that of importance 2 but with duration ≥1.5 hours can significantly disturb the cosmic ray intensity. The flares located near the solar central meridian can cause the larger FDs than that located at the limb. In this paper it is found that a SF flare located at the limb, having long duration and being strong X-ray burst enough or accompanying by a energetic event having quite long duration, can also produce the obvious FDs.