Stratospheric Aerosol Optical Thickness

Data source: Updates of M. Sato, J.E. Hansen, M.P. McCormick and J.B. Pollack (1993) "Stratospheric Aerosol Optocal Depth, 1850-1990", JGR, 98, 22,987-22,994. We thank Dr. Larry Thomason of NASA Langley Research Center for providing us 1991-2007 data. Data source for 2008-2010 is J.M. Haywood et al. (2010) "Observations of the eruption of the Sarychev volcano and simulations using the HadGEM2 climate model", JGR, 115, D21212.

The relation between the optical thickness and the forcings are roughly.

• instantaneous forcing Fi (W/m²) = -27 τ
• adjusted forcing Fa (W/m²) = -25 τ
• SST-fixed forcing Fs (W/m²) = -26 τ
• effective forcing Fe (W/m²) = -23 τ

Source: J. Hansen, et al. (2005), "Efficacy of climate forcings", JGR, 110, D1104.

See a NASA/GISS page for more information.

(Last modified: 2011/06/29)