AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
Abstract View
Influence of Brown Carbon Aerosol Deposition on Snow Surface Reflection Spectra
NICHOLAS D BERES, Deep Sengupta, Vera Samburova, Andrey Khlystov, Hans Moosmuller, Desert Research Institute
Abstract Number: 658 Working Group: Carbonaceous Aerosols in the Atmosphere
Abstract Brown carbon (BrC) is form of light-absorbing organic carbon with a brownish or yellowish visual appearance caused by an imaginary part of the refractive index that increases strongly towards shorter visible and ultraviolet wavelengths, resulting in an absorption Ångström exponent much larger than one. Recently, optical properties of BrC aerosols have become the topic of intense research. However, very little is known about how BrC deposition onto snow surfaces affects the spectrum of their albedo and their radiative forcing.
We generated BrC aerosols through small-scale, smoldering biomass combustion and deposited them onto natural snow surfaces in the Carson Range of the Sierra Nevada, USA. After deposition, we monitored the spectral reflectivity of these disturbed snow surfaces and of adjacent undisturbed snow surfaces with a field spectroradiometer (ASD FieldSpec 3). We observed a strong reduction of snow surface reflectivity in the blue and ultraviolet spectral regions. We also will discuss (1) the temporal evolution of the snow surface reflectivity after BrC deposition, (2) modeling results for the influence of deposited BrC on snow surface albedo, and (3) BrC-on-snow radiative forcing.