Study on the Relationship between Large Volcanic Eruptions and Temperature Variation Based on Tree-Ring Data in the Eastern Tibetan Plateau during the Past Millennium
Volcanic eruptions can significantly cool the global troposphere on the time scales from several months up to a decade due to reflection of solar radiation by sulfate aerosols and feedback mechanisms in the climate system. The impact of volcanic eruptions on global climate are discussed in many studies. However,few studies have been done on the impact of volcanic eruption on climate change in China in the past millennium. The 1300-year and 600-year temperature series were reconstructed based on the six tree-ring temperature proxy data in northeastern and southeastern Tibetan Plateau,respectively. Three warm periods occurred in 670-920,1000-1310 and 1590-1930,and three cold periods happened at 920-1000, 1310-1590 and 1930-2000 in the northeastern Tibetan Plateau. There were two obviously warm periods ( 1385-1450 and 1570-1820) and two cold periods ( 1450-1570 and 1820-2000) in southeastern Tibetan Plateau. Contrasting with volcanic eruption chronology,we analyzed the relationship between volcanic activity and temperature variation in the eastern Tibetan plateau during the past millennium using Superposed Epoch Analysis ( SEA) method. The results indicated that the temperature decreased one year after large volcanic eruptions located beteen 10°S and 10°N in latitude in northeastern Tibetan Plateau and two years in southeastern Tibetan Plateau. The volcanic eruptions occurred at different latitudes have different impacts on the temperature variations,which may be caused by regional difference,the nature of the eruption,the magnitude of the resulting change in incoming solar radiation,prevailing background climate and internal variability,season, latitude,and other considerations.