20世纪以来强火山喷发对中国温度变化区域差异的影响

本文根据1901年以来的62次强火山(VEI≥4)喷发年表和英国东安格利亚大学气候研究中心发布的格点气温资料(CRU TS v.3.22),采用时序叠加分析方法,辨识了不同纬度、不同季节强火山喷发对中国温度变化区域差异的影响。结果表明：不同纬度强火山喷发后的1~2年,中国温度基本以下降为主,但降温强度存在显著的区域与季节差异。高纬火山喷发后的显著降温区域发生在东北和东南地区,冬半年温度下降达1.2°C,夏半年温度下降2.0°C;中低纬火山喷发后,冬半年温度的显著下降区域发生在青藏、东南和东中部地区,幅度为1.3~2.2°C,夏半年温度下降幅度比冬半年小;赤道火山喷发后,冬半年温度显著下降区域发生在东北、东南和青藏地区,且降温幅度均大于1.2°C,夏半年西北和东中部地区降温幅度偏小。此外,强火山喷发后第3年,部分地区还出现二次降温现象,降幅甚至超过第一次;然而,同一纬度强火山喷发后,其所造成的降温幅度和降温区域差异与强火山喷发的季节关系不大。

Regional differences in temperature response in China to the large volcanic eruptions since the 20th century

Based on the chronology of 62 large volcanic eruption events (Volcanic Explosivity Index≥4) since 1901 and gridded CRU TS v.3.22 monthly dataset from the Climatic Research Unit at the University of East Anglia, we examined the effects of large volcanic eruptions by different eruptive latitude bands and seasons on regional difference of temperature in China, using superposed epoch analysis (SEA). The results show that temperature decreased in most regions in 1~2 years after large volcanic eruptions at all latitude bands, but there were clear differences in cooling intensity of different regions and seasons. After volcanic eruptions in high latitude areas, temperature decreased in Northeast and Southeast China by 1.2°C in the winter half-year and 2.0°C in the summer half-year. After middle- and lower-latitudes volcanic eruptions, the cooling regions of the winter half-year were Tibet, Southeast, and Central East China, where the temperature decreased by 1.3~2.2°C; the cooling effects in the summer half-year were less intense than in the winter half-year. After equatorial volcanic eruptions, the winter half-year temperature significantly decreased in Northeast, Southeast, and Tibet, and the cooling magnitudes were greater than 1.2°C; the post-volcanic summer half-year temperature decreased slightly in Northwest and Central East. In some regions secondary cooling occurred in the third year after large volcanic eruptions, and the cooling intensity was even stronger than the initial temperature drop. However, we did not find significant relationship between the cooling magnitude and region and the eruptive seasons of large volcanos of the same latitude bands.