Observational constraints on ambient brown carbon with IMPROVE network observations
Abstract
The light-absorbing component of organic aerosols, often referred to as brown carbon (BrC), represents a major uncertainty in current estimates of aerosol radiative forcing. The fate of BrC remains largely uncertain, due to lack of extensive evaluation with field observations. Recently, the Interagency Monitoring of Protected Visual Environments (IMPROVE) network starts to provide measurements of aerosol absorption at multiple wavelengths, allowing quantification of brown carbon in a regional scale. Here we use IMPROVE network observations, combined with a global chemical transport model (GEOS-Chem), to examine the magnitude, seasonality and spatial distribution of BrC in the United States. Our model shows reasonable agreement with observations on the magnitude and spatial distribution of organic carbon mass and brown carbon absorption aerosol optical depth (AAOD). We also find that model without photobleaching tends to overestimate BrC AAOD, suggesting an important role of photobleaching on the fate of BrC.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.A14D..06M
- Keywords:
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- 0305 Aerosols and particles;
- ATMOSPHERIC COMPOSITION AND STRUCTURE;
- 0322 Constituent sources and sinks;
- ATMOSPHERIC COMPOSITION AND STRUCTURE;
- 0345 Pollution: urban and regional;
- ATMOSPHERIC COMPOSITION AND STRUCTURE;
- 0365 Troposphere: composition and chemistry;
- ATMOSPHERIC COMPOSITION AND STRUCTURE