Abstract:
[from NOAA/NCDC/WDC Paleoclimatology]
A new compilation of annually resolved time series of atmospheric
trace gas concentrations, solar irradiance, tropospheric aerosol
optical depth, and stratospheric (volcanic) aerosol optical depth is
presented for use in climate modeling studies of the period 1500 to
1999 A.D. Atmospheric CO2, CH4, and N2O concentrations
... over this
period are well established on the basis of fossil air trapped in ice
cores and instrumental measurements over the last few
decades. Estimates of solar irradiance, ranging between 1364.2 and
1368.2 W/m2, are presented using calibrated historical observations of
the Sun back to 1610, along with cosmogenic isotope variations
extending back to 1500. Tropospheric aerosol distributions are
calculated by scaling the modern distribution of sulfate and
carbonaceous aerosol optical depths back to 1860 using reconstructed
regional CO2 emissions; prior to 1860 the anthropogenic tropospheric
aerosol optical depths are assumed to be zero. Finally, the first
continuous, annually dated record of zonally averaged stratospheric
(volcanic) optical depths back to 1500 is constructed using sulfate
flux data from multiple ice cores from both Greenland and Antarctica,
in conjunction with historical and instrumental (satellite and
pyrheliometric) observations. The climate forcings generated here are
currently being used as input to a suite of transient (time dependent)
paleoclimate model simulations of the past 500 years. These forcings
are also available for comparison with instrumental and proxy
paleoclimate data of the same period. 
