火山活动是影响全球气候变化的重要自然因子。在年代际预测试验中加入火山气溶胶强迫会带来火山爆发后短期内气候响应回报技巧的改变。基于耦合气候系统模式FGOALS-s2的中国科学院大气物理研究所年代际气候预测试验(DP-EnOI-IAU试验)结果,分析了火山活动对太平洋海温年代际预测技巧的影响。DP-EnOI-IAU试验引入了平流层火山气溶胶的辐射外强迫变化,在模拟的1960—2005年共发生4次强的热带火山爆发事件。结果表明,DP-EnOI-IAU试验在多数年份对太平洋海温具有显著的预测技巧,但预测技巧在1982年El Chichon火山爆发和1991年Pinatubo火山爆发后显著下降。模式对火山爆发后ENSO位相的模拟偏差导致了其对太平洋海温年代际预测技巧的下降。对于1982年El Chichon火山爆发,在火山爆发峰值时期和第3年冬季,赤道中东太平洋均表现出与观测相反的海温型响应,使得DP-EnOI-IAU试验对太平洋海温的年代际预测技巧显著下降。在1991年Pinatubo火山爆发后的秋冬季和第3年冬季,观测和模拟的热带海温型亦相反,模式对1991年火山爆发后太平洋海温的预测技巧降低。相对于1982年El Chichon和1991年Pinatubo火山爆发,模式对1963年Agung火山爆发后热带海温型响应的模拟与观测较为一致,此次火山爆发没有带来太平洋海温预测技巧的显著下降。

Explosive volcanic eruptions are known to be a leading cause of natural climate change. There has been a growing recognition that there is a measurable climate system response even to moderate-sized volcanic eruptions. In this study, we investigated the hindcast skills of the Pacific Sea Surface Temperatures (SSTs) using the hindcast experiments based on the near-term climate prediction system DecPreS developed by the Institute of Atmospheric Physics (IAP)(hereafter DP-EnOI-IAU experiments). The DP-EnOI-IAU experiments were run for initial years from 1960 to 2005. These hindcasts took into account observed stratospheric aerosol concentrations that included the four large tropical volcanic eruptions during that period. The time evolution over the entire hindcast period for skill in predicting the patterns of the 3~7 year prediction averages for Pacific SSTs showed that there was statistically significant skill for most years except for a dramatic drop in skill during the 1980s and 1990s. Decadal hindcast skill is reduced if the post-eruption model response deviates the internal El Niño variability in the observations. The simulations showed a post-eruption SST of a La Niña-like pattern in the third northern winter after the 1982 El Chichon eruption and a El Niño-like pattern after the 1991 Pinatubo eruption, which were opposite in sign to what was in the observations. This lead to the loss of hindcast skill for years in the 1980s and 1990s affected by the eruptions. Agung (1963) happened to have post-eruption Pacific SSTs more similar to the observations and thus did not degrade prediction skill in the hindcasts.