The Volcanic Signal in Surface Temperature Observations

Abstract

Climate records of the past 140 years are examined for the impact of major volcanic eruptions on surface temperature. After the low-frequency variations and El Niño/Southern Oscillation signal are removed, it is shown that for 2 years following great volcanic eruptions, the surface cools significantly by 0.1 °-0.2 oC in the global mean, in each hemisphere, and in the summer in the latitude bands 00_30 0 S and 00_30 0 N and by 0.3°C in the summer in the latitude band 30°-60 0 N. By contrast, in the first winter after major tropical eruptions and in the second winter after major high-latitude eruptions, North America and Eurasia warm by several degrees, while northern Africa and southwestern Asia cool by more than 0.5°C. Because several large eruptions occurred at the same time as ENSO events, the warming produced by the EN SO masked the volcanic cooling during the first year after the eruption. The timescale of the ENSO response is only 1 year while the volcanic response timescale is 2 years, so the cooling in the second year is evident whether the EN SO signal is removed or not. These results, both the global cooling and Northern Hemisphere continental winter warming, agree with general circulation model calculations.

Observations of volcanic SO<sub>2</sub> from MLS on Aura

“…These particles alter the albedo of the Earth, reflecting a fraction of sunlight back into space and thereby reducing the Earth's temperature. Based on six of the largest eruptions of between 1875 and 1991, Robock and Mao (1995) show that the cooling can be on the order of 0.1 to 0.2 • C.…”

Identification and separation of Mount Pinatubo and El Niño‐Southern Oscillation land surface temperature anomalies

“…The aerosol particles converted from the Pinatubo SO2 injection were suspended in the atmosphere for several years and caused the largest aerosol perturbation to the stratosphere in the twentieth century. The scattering and absorption of solar radiation and the absorption of terrestrial radiation by the Pinatubo aerosol largely disturbed the radiation balance of the atmosphere [Stenchikov et In previous studies [Angell, 1988;Mass and Portman, 1989;Robock and Mao, 1995], SOI and area-averaged SST over the eastern tropical Pacific were used to represent and measure the strength of ENSO events, and attention was paid to the area-averaged surface or atmospheric temperature changes following volcanic eruptions. Here we focus on the geographical distributions of the observed SAT and their seasonal characteristics over land during the 3 years •bllowing the Pinatubo eruption, together with the corresponding changes in SST over the eastern tropical Pacific.…”

An interdecadal climate cycle in the South Atlantic and its links to other ocean basins

“…Some have suggested that decadal to interdecadal variability can be phase locked by external signals such as variations in solar radiation [ White el al., 1997] and volcanic eruptions [Robock and Mao, 1995].…”