A global dataset of atmospheric aerosol optical depth and surface reflectance from AATSR
2012
Bevan, Suzanne L. | North, Peter R.J. | Los, Sietse O. | Grey, William M.F.
We present a new global dataset of aerosol properties and surface reflectance derived from the AATSR instrument for the period 2003–2009. The algorithm retrieves aerosol optical depth (AOD) and aerosol type over a wide variety of surfaces including ocean, vegetated land and desert. The AATSR dual-view allows retrieval without prior information about land surface reflectance. Results show global mean values of AOD at 550nm over land of 0.195, and over ocean of 0.137. The datasets are compared with sun photometer measurements from AERONET and the Maritime Aerosol Network (MAN), and with MODIS and MISR aerosol products. Agreement with AERONET (r=0.80; Δτ=±0.025±0.4τ) and MAN (r=0.97; Δτ=±0.04) was high. Estimates of aerosol coarse/fine mode classification where τ>0.2 show 71% correspondence over land and 81% over ocean. Monthly AOD from MODIS, MISR and AATSR showed close agreement over most regions. However, over deserts AATSR estimates were higher than MODIS or MISR, while over southern oceans both AATSR and MODIS were lower than MISR. Global composites show aerosol sources of desert dust, anthropogenic pollution, biomass burning, and their transport. Aerosol radiative forcing is a major source of uncertainty in climate modelling; this newly derived dataset gives spatially and temporally comprehensive fields of aerosol properties suitable to constrain global models and to analyse regional and global trends.
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