氏名： 室谷 宏一
指導教官： 守田 治
It was considered that this unusual weather was caused by the eruption of Mt. Pinatubo on 15 June 1991. This event was already investigated by many researchers using the observationed data from the orbital satellite SAGE I I [e.g. McCormick et al. , 1992 ], or using climate models [e.g. Hansen et al. , 1992]. While, it is well known that the El Nino event in 1991/1992 h ad influenced on the surface temperature in the midlatitude of the northern hemisphere.
In this thesis, the effect of the eruption of Mt. Pinatubo and the El Nin o event on surface temperature in the midlatitude of the northern hemispher e is researched by the correlational analysis and the causal analysis. The result of the analysis clearly suggests that the eruption of Mt. Pinatubo i nfluenced largely on the surface temperature but the El Nino event did not so much as the former.