Abstract:

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.

Key words: since the 20th century, large volcanic eruption, temperature change, regional difference, China