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Title: Aerosols at the poles: an AeroCom Phase II multi-model evaluation

Atmospheric aerosols from anthropogenic and natural sources reach the polar regions through long-range transport and affect the local radiation balance. Such transport is, however, poorly constrained in present-day global climate models, and few multi-model evaluations of polar anthropogenic aerosol radiative forcing exist. Here we compare the aerosol optical depth (AOD) at 550 nm from simulations with 16 global aerosol models from the AeroCom Phase II model intercomparison project with available observations at both poles. We show that the annual mean multi-model median is representative of the observations in Arctic, but that the intermodel spread is large. We also document the geographical distribution and seasonal cycle of the AOD for the individual aerosol species: black carbon (BC) from fossil fuel and biomass burning, sulfate, organic aerosols (OAs), dust, and sea-salt. For a subset of models that represent nitrate and secondary organic aerosols (SOAs), we document the role of these aerosols at high latitudes. The seasonal dependence of natural and anthropogenic aerosols differs with natural aerosols peaking in winter (sea-salt) and spring (dust), whereas AOD from anthropogenic aerosols peaks in late spring and summer. The models produce a median annual mean AOD of 0.07 in the Arctic (defined here as north ofmore » 60° N). The models also predict a noteworthy aerosol transport to the Antarctic (south of 70° S) with a resulting AOD varying between 0.01 and 0.02. The models have estimated the shortwave anthropogenic radiative forcing contributions to the direct aerosol effect (DAE) associated with BC and OA from fossil fuel and biofuel (FF), sulfate, SOAs, nitrate, and biomass burning from BC and OA emissions combined. The Arctic modelled annual mean DAE is slightly negative (-0.12 W m -2), dominated by a positive BC FF DAE in spring and a negative sulfate DAE in summer. The Antarctic DAE is governed by BC FF. We perform sensitivity experiments with one of the AeroCom models (GISS modelE) to investigate how regional emissions of BC and sulfate and the lifetime of BC influence the Arctic and Antarctic AOD. A doubling of emissions in eastern Asia results in a 33 % increase in Arctic AOD of BC. A doubling of the BC lifetime results in a 39 % increase in Arctic AOD of BC. However, these radical changes still fall within the AeroCom model range.« less
Authors:
 [1] ;  [2] ; ORCiD logo [3] ;  [4] ;  [5] ;  [6] ;  [7] ;  [8] ;  [9] ;  [10] ;  [10] ;  [11] ;  [11] ; ORCiD logo [12] ;  [10] ;  [13] ;  [14] ;  [2] ;  [15] ;  [16] more »; ORCiD logo [11] ;  [11] ; ORCiD logo [2] ; ORCiD logo [17] ;  [18] ; ORCiD logo [4] ;  [14] ;  [19] ;  [20] « less
  1. Center for International Climate and Environmental Research – Oslo (CICERO) (Norway); NASA Goddard Inst. for Space Studies (GISS), New York, NY (United States). Columbia Earth Inst.
  2. Center for International Climate and Environmental Research – Oslo (CICERO) (Norway)
  3. Inst. Pierre Simon Laplace, Gif-sur-Yvette (France). Climate and Environment Sciences Lab. (LSCE)
  4. NASA Goddard Inst. for Space Studies (GISS), New York, NY (United States). Columbia Earth Inst.
  5. Univ. of Reading (United Kingdom). Dept. of Meteorology
  6. Center for International Climate and Environmental Research – Oslo (CICERO) (Norway); Univ. of Oslo (Norway). Dept. of Geosciences
  7. Univ. of Maryland, College Park, MD (United States). Earth System Science Interdisciplinary Center
  8. NASA Goddard Space Flight Center (GSFC), Greenbelt, MD (United States)
  9. European Commission, Ispra (Italy). Directorate for Sustainable Resources. Joint Research Centre
  10. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
  11. Norwegian Meteorological Inst., Oslo (Norway)
  12. National Center for Atmospheric Research, Boulder, CO (United States)
  13. Univ. of Wyoming, Laramie, WY (United States). Dept. of Atmospheric Science
  14. State Univ. of New York at Albany, NY (United States). Atmospheric Sciences Research Center
  15. Royal Netherlands Meteorological Inst., De Bilt (Netherlands)
  16. Univ. of Michigan, Ann Arbor, MI (United States). Climate and Space Sciences and Engineering
  17. Univ. of Oxford (United Kingdom). Dept. of Physics
  18. Kyushu Univ., Fukuoka (Japan). Research Inst. for Applied Mechanics
  19. Max Planck Inst. for Meteorology, Hamburg (Germany); Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
  20. China Meteorological Administration, Beijing (China). Lab. for Climate Studies. National Climate Center
Publication Date:
Report Number(s):
PNNL-SA-122987
Journal ID: ISSN 1680-7324
Grant/Contract Number:
AC05-76RL01830; FG02-01ER63248; SC0008486; NNX17AG35G; AGS-0946739; AGS-1550816; ARC-1023387; ns2345k; nn2345k; 207711/E10; 240921; 240372; 229771; FP7-280025; 608695; JP15H01728; JP15K12190; NE/J022624/1
Type:
Accepted Manuscript
Journal Name:
Atmospheric Chemistry and Physics (Online)
Additional Journal Information:
Journal Name: Atmospheric Chemistry and Physics (Online); Journal Volume: 17; Journal Issue: 19; Journal ID: ISSN 1680-7324
Publisher:
European Geosciences Union
Research Org:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Univ. of Michigan, Ann Arbor, MI (United States); NASA Goddard Inst. for Space Studies (GISS), New York, NY (United States); Center for International Climate and Environmental Research – Oslo (CICERO) (Norway); Norwegian Meteorological Inst., Oslo (Norway); Kyushu Univ., Fukuoka (Japan); Univ. of Oxford (United Kingdom)
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23); National Aeronautic and Space Administration (NASA); National Science Foundation (NSF); Research Council of Norway (RCN); European Research Council (ERC); Japan Society for the Promotion of Science (JSPS); Natural Environment Research Council (NERC) (United Kingdom)
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES
OSTI Identifier:
1430718