Journal article
Global budget and radiative forcing of black carbon aerosol: Constraints from pole‐to‐pole (HIPPO) observations across the Pacific
Journal of geophysical research. Atmospheres, Vol.119(1), pp.195-206
01/16/2014
DOI: 10.1002/2013JD020824
Abstract
We use a global chemical transport model (GEOS‐Chem) to interpret aircraft curtain observations of black carbon (BC) aerosol over the Pacific from 85°N to 67°S during the 2009–2011 HIAPER (High‐Performance Instrumented Airborne Platform for Environmental Research) Pole‐to‐Pole Observations (HIPPO) campaigns. Observed concentrations are very low, implying much more efficient scavenging than is usually implemented in models. Our simulation with a global source of 6.5 Tg a−1 and mean tropospheric lifetime of 4.2 days (versus 6.8 ± 1.8 days for the Aerosol Comparisons between Observations and Models (AeroCom) models) successfully simulates BC concentrations in source regions and continental outflow and captures the principal features of the HIPPO data but is still higher by a factor of 2 (1.48 for column loads) over the Pacific. It underestimates BC absorbing aerosol optical depths (AAODs) from the Aerosol Robotic Network by 32% on a global basis. Only 8.7% of global BC loading in GEOS‐Chem is above 5 km, versus 21 ± 11% for the AeroCom models, with important implications for radiative forcing estimates. Our simulation yields a global BC burden of 77 Gg, a global mean BC AAOD of 0.0017, and a top‐of‐atmosphere direct radiative forcing (TOA DRF) of 0.19 W m−2, with a range of 0.17–0.31 W m−2 based on uncertainties in the BC atmospheric distribution. Our TOA DRF is lower than previous estimates (0.27 ± 0.06 W m−2 in AeroCom, 0.65–0.9 W m−2 in more recent studies). We argue that these previous estimates are biased high because of excessive BC concentrations over the oceans and in the free troposphere.
Key Points
A global distribution of BC is simulated in GEOS‐Chem
Results imply more efficient BC removal than is usually included in models
Previous estimates of DRF from BC were biased high due to excessive remote BC
Details
- Title: Subtitle
- Global budget and radiative forcing of black carbon aerosol: Constraints from pole‐to‐pole (HIPPO) observations across the Pacific
- Creators
- Qiaoqiao Wang - Harvard UniversityDaniel J Jacob - Harvard UniversityJ. Ryan Spackman - National Oceanic and Atmospheric AdministrationAnne E Perring - University of Colorado BoulderJoshua P Schwarz - University of Colorado BoulderNobuhiro Moteki - University of TokyoEloïse A Marais - Harvard UniversityCui Ge - University of Nebraska‐LincolnJun Wang - University of Nebraska‐LincolnSteven R. H Barrett - Massachusetts Institute of Technology
- Resource Type
- Journal article
- Publication Details
- Journal of geophysical research. Atmospheres, Vol.119(1), pp.195-206
- DOI
- 10.1002/2013JD020824
- ISSN
- 2169-897X
- eISSN
- 2169-8996
- Number of pages
- 12
- Language
- English
- Date published
- 01/16/2014
- Academic Unit
- Iowa Technology Institute; Physics and Astronomy; Civil and Environmental Engineering; Chemical and Biochemical Engineering; Electrical and Computer Engineering
- Record Identifier
- 9984104812802771
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