Aerosol Optical Properties from MERRA-2 Reanalysis

Authors : Fabien Solmon (LAERO, OMP, [e-mail]) with the contribution of Virginie Buchard and Arlindo Moraes da Silva Jr (NASA, GMAO).

Global distribution of monthly aerosol optical properties (extinction, single scattering albedo and assymetry parameter) created from the NASA MERRA-2 3-hourly reanalysis profiles of aerosol mixing ratio and relative humidity, and MERRA-2 species level aerosol optical properties for different humidities and spectral bands. The data are meant to be used in climate model or for other applications requiring aerosol optical properties. Data are generated on the native MERRA2 vertical coordinate grid along with correponding MERRA2 surface pressure, pressure layer thickness and layer air density fields. Different spectral bands refering to the RRTMG spectral intervals are proposed in distinct directories, and monthly file names are also flagged according to wave band wb_X ( e.g. wb_10 refers to RRTMG band 10, visible),

Details of RRTMG short wave bands are provided hereafter (wavelenght interval and mean value in nm). Interpolation might be necessary to fit specific radiative transfer scheme
wb # 1 2 3 4 5 6 7 8 9 10 11 12 13 14
λav : 3462 2789 2325 2046 1784 1463 1271 1010.1 701.6 533.2 393.1 304.0 231.6 8021
λmin : 3077 2500 2150 1942 1626 1299 1242 778.2 625.0 441.5 344.8 263.2 200.0 3846
λmax : 3846 3077 2500 2150 1942 1626 1299 1242.0 778.2 625.0 441.5 344.8 263.2 12195
For longwave, only one wave band (#19) is provided. This band has been chosen to represent an average value regarding dust and sea salt extinction spectral dependency in the longwave spectrum.