The values for 1850, 1950 and 1990 are shown in the following figure. The 1850 to 1990 and 1950 to 1990 changes in the optical thickness are shown in the bottom panel.
The sources for most of the aerosol data are discussed by Tegen et al. (2000) and Koch (2001). Industrial black carbon (BC) distributions were calculated at 10 year intervals using the GISS tracer transport model using the method described by Cooke and Wilson (1996) to derive BC emissions from a United Nations energy statistics data base. BC from biomass burning and natural organic carbon (OC) are from Liousse et al. (1996). Industrial OC emissions are assumed to be four times those of industrial BC, following Liousse et al. (1996). Soil dust is based on Tegen and Fung (1995) and Tegen and Lacis (1996). The sea salt distribution is based on Tegen et al. (1997), but the optical depths have been multiplied by four as suggested by Quinn and Coffman (1999) and Haywood et al. (1999).
|Tropospheric Aerosol Optical Thickness and Single Scattering Albedo for SI2002 and SI2004 Models|
|Optical Thickness × 100||Single Scattering Albedo|
The geographic distributions of these aerosols are shown in the maps below. (Some corrections were made by A. Lacis in September 2003.), The maps figure is also available as a PDF.
We have data for the geographic distributions of the aerosols at 1875, 1900, 1925, 1950, 1960, 1970, 1980 and 1990. Assuming there was no industrial aerosols in 1850, we interpolate between the data linearly for 1850 to 1950, and for 1950 to 1990 interpolate between the data using the annual emissions data as shown in parts (a) and (b) of the figure below, where the sulfate curve is applied to anthropogenic sulfate and the BC curve is used for industrial BC and industrial OC. And after 1990 the aerosols are assumed to be constant.
Color version of "Figure 3. Estimated fossil-fuel BC emissions" from Novakov et al. (2003); also available as a PDF.
The global-mean changes in optical thickness and forcing is given in the graphs below.
The geographic distributions for the forcing is shown in the maps below.
Download forcing data:
Download additional data:
Click for D. Koch's three-dimensional aerosol mass data.
Additional information is available on the soil dust aerosols datasets page.
Related figures (PDF) from Sato et al. (2003):
Cooke, W.F. and J.N. Wilson, 1996: A global black carbon aerosol model, J. Geophys. Res. 101, 19395-19409.
Haywood, J.M., V. Ramaswamy and B.J. Soden, 1999: Tropospheric aerosol forcing in clear-sky satellite observations over the oceans, Science 283, 1299-1303.
Koch, D., D. Jacob, I. Tegen, D. Rind and M. Chin, 1999: Tropospheric sulfur simulation and sulfate direct radiative forcing in the Goddard Institute for Space Studies general circulation model. J. Geophys. Res. 104, 23799-23822.
Koch, D., 2001: Transport and direct radiative forcing of carbonaceous and sulfate aerosols in the GISS GCM. J. Geophys. Res. 106, 20311-20332, doi:10.1029/2001JD900038.
Koch, D., S. Bauer, A. Del Genio, G. Faluvegi, J.R. McConnell, S. Menon, R.L. Miller, D. Rind, R. Ruedy, G.A. Schmidt, and D. Shindell, 2011: Coupled aerosol-chemistry-climate twentieth century transient model investigation: Trends in short-lived species and climate responses. J. Climate, 24, 2693-2714, doi:10.1175/2011JCLI3582.1.
Liousse, C. J.E. Penner, C. Chuang, J.J. Walton, H. Eddleman and H. Cachier, 1996: A global three-dimensional model study of carbonaceous aerosols, J. Geophys. Res. 101, 19411-19432.
Novakov, T., V. Ramanathan, J.E. Hansen, T.W. Kirchstetter, M. Sato, J.E. Sinton, and J.A. Satahye, 2003: Large historical changes of fossil-fuel black carbon aerosols, Geophys. Res. Lett. 30, 6, 1324-1327, doi:10.1029/2002GL016345.
Quinn, P.K. and D.J. Coffman, 1999: Comment on "Contribution of different aerosol species to the global aerosol extinction optical thickness: Estimates of model results" by Tegen et al., J. Geophys. Res. 104, 4241-4248.
Sato, M., J. Hansen, D. Koch, A. Lacis, R. Ruedy, O. Dubovik, B. Holben, M. Chin, and T. Novakov, 2003: Global atmospheric black carbon inferred from AERONET. Proc. Natl. Acad. Sci., 100, 6319-6324, doi:10.1073/pnas.0731897100.
Tegen, I. and I. Fung, 1995: Contribution to the mineral aerosol load from land surface modification. J. Geophys. Res. 100, 18707-18726, 1995.
Tegen, I. and A.A. Lacis, 1996: Modeling of particle size distribution and its influence on the radiative properties of mineral dust aerosol. J. Geophys. Res. 101, 19237-19244.
Tegen, I., P. Hollrigl, M. Chin, I. Fung, D. Jacob and J. Penner, 1997: Contribution of different aerosol species to the global aerosol extinction optical thickness: Estimates from model results. J. Geophys. Res. 102, 23895-23915.
Tegen, I., D. Koch, A.A. Lacis and M. Sato, 2000: Trends in tropospheric aerosol loads and corresponding impact on direct radiative forcing between 1950 and 1990: A model study. J. Geophys. Res. 105, 26971-26989.b