Spatial and Temporal Variability of Brown Carbon in the United States: Implications for Direct Radiative Effects
Geophysical Research Letters
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© 2020. American Geophysical Union. All Rights Reserved. A newly developed data set from the Interagency Monitoring of PROtected Visual Environments (IMPROVE) observation network, combined with a 3-D chemical transport model, is used to evaluate the spatial and temporal variability of brown carbon (BrC) in the United States. The model with BrC emitted from biomass burning and biofuel emissions agrees with the seasonal and spatial variability of BrC planetary boundary layer (PBL) absorption aerosol optical depth (AAOD) observations within a factor of 2. The model without whitening, the tendency for absorption to decrease with aerosol aging, overestimates the observed BrC PBL AAOD and does not reflect the measured BrC PBL AAOD spatial variability. The model shows higher absorption direct radiative effects (DRE) from BrC at northern high latitudes than at midlatitudes in spring and summer, due to boreal fire emissions, long whitening lifetimes, and high surface albedos. These findings highlight the need to study BrC over the Arctic region.
Absorption aerosol optical depth; Arctic warming; Biomass burning; Brown carbon; Radiative effect; Whitening
Environmental Health | Radiochemistry
Spatial and Temporal Variability of Brown Carbon in the United States: Implications for Direct Radiative Effects.
Geophysical Research Letters, 47(23),