Sensitivity of radiative forcing to global carbonaceous emissions

Abstract

Direct radiative forcing at top of the atmosphere for black carbon aerosols from two inventories comes out to be +0.33W m -2 for Global Emission Inventory Activity (GEIA) and +0.14W m -2 for BOND (Bond et al., 2004). However, for organic matter aerosols, it is simulated as -0.44W m -2 for GEIA and -0.11W m -2 with BOND inventory. Simulated annual global burden and aerosol optical depth of carbonaceous aerosols from GEIA and BOND are also compared. Normalised differences plots show that model simulates generally higher values of carbonaceous aerosols with GEIA, which are far superior in some parts of the globe as compared to those simulated with BOND emission inventory. An evaluation of these quantities with the median of the response of the AeroCom models is considered here as a benchmark -shows that while simulations with GEIA inventory have closer agreement, values of radiative forcing with BOND inventory are comparatively of smaller magnitudes over most parts of the globe. The reasons for this disparity in results for the latter may possibly be attributed to key differences between the two inventories. The main conclusion of this study is that the radiative forcing appears to be highly sensitive to carbonaceous content in aerosol compositions. © 2012 H. Fatima et al.