T. Hibino, and M. Fujiwara (presenting)

Global temperature response to the large-scale volcanic eruptions in 9 reanalysis data sets

Global temperature response to the eruptions of El Chichon in 1982 and Pinatubo in 1991 is investigated using 9 reanalysis data sets (i.e., ERA-40, ERA-Interim, JRA-25/JCDAS, JRA-55, MERRA, NCEP/NCAR, NCEP/DOE, NCEP-CFSR, and 20CR) during the period from 1979 to 2009 (2001 for ERA-40; 2004 for JRA-55). The multiple linear regression is applied to the zonal and monthly mean temperature time series by considering the components of seasonal variations, linear trends, Quasi-Biennial Oscillation (QBO), solar activity, El Nino Southern Oscillation (ENSO), and Indian Ocean Dipole Mode. The residuals are used to define the volcanic signals. Latitude-altitude distributions of the volcanic signals and of the regression coefficients are compared and discussed among the different reanalyses. Most reanalyses show statistically significant negative and positive temperature anomalies in the tropical troposphere and in the tropical lower stratosphere, respectively, in response to the Pinatubo eruption. The signals are similar for the El Chichon eruption, with the tropospheric response statistically insignificant.
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