Articles | Volume 14, issue 5
Atmos. Chem. Phys., 14, 2399–2417, 2014
Atmos. Chem. Phys., 14, 2399–2417, 2014
Research article
07 Mar 2014
Research article | 07 Mar 2014

An AeroCom assessment of black carbon in Arctic snow and sea ice

C. Jiao1, M. G. Flanner1, Y. Balkanski2, S. E. Bauer3,4, N. Bellouin5,*, T. K. Berntsen6, H. Bian7, K. S. Carslaw8, M. Chin9, N. De Luca10, T. Diehl9, S. J. Ghan11, T. Iversen12, A. Kirkevåg12, D. Koch13, X. Liu11,14, G. W. Mann8, J. E. Penner1, G. Pitari10, M. Schulz12, Ø. Seland12, R. B. Skeie15, S. D. Steenrod16, P. Stier17, T. Takemura18, K. Tsigaridis3,4, T. van Noije19, Y. Yun20, and K. Zhang11,21 C. Jiao et al.
  • 1Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, Ann Arbor, MI, USA
  • 2Laboratoire des Sciences du Climat et de l'Environnement, CEA-CNRS-UVSQ, Gif-sur-Yvette, France
  • 3Center for Climate Systems Research, Columbia University, New York, NY, USA
  • 4NASA Goddard Institute for Space Studies, New York, NY, USA
  • 5Met Office Hadley Centre, Exeter, UK
  • 6Department of Geosciences, University of Oslo, Oslo, Norway
  • 7University of Maryland, Baltimore County, MD, USA
  • 8Institute for Climate and Atmospheric Science, School of Earth and Environment, University of Leeds, Leeds, UK
  • 9NASA Goddard Space Flight Center, Greenbelt, MD, USA
  • 10Dipartimento di Scienze Fisiche e Chimiche, Università degli Studi L'Aquila, Coppito, L'Aquila, Italy
  • 11Pacific Northwest National Laboratory, Richland, WA, USA
  • 12Norwegian Meteorological Institute, Oslo, Norway
  • 13Department of Energy, Office of Biological and Environmental Research, USA
  • 14Department of Atmospheric Science, University of Wyoming, Laramie, WY, USA
  • 15Center for International Climate and Environmental Research-Oslo (CICERO), Oslo, Norway
  • 16University Space Research Association, MD, USA
  • 17Department of Physics, University of Oxford, Oxford, UK
  • 18Research Institute for Applied mechanics, Kyushu University, Fukuoka, Japan
  • 19Royal Netherlands Meteorological Institute, De Bilt, the Netherlands
  • 20Geophysical Fluid Dynamics Laboratory, NOAA, P.O. Box 308, Princeton, NJ, USA
  • 21Max Planck Institute for Meteorology, Hamburg, Germany
  • *now at: Department of Meteorology, University of Reading, Reading, UK

Abstract. Though many global aerosols models prognose surface deposition, only a few models have been used to directly simulate the radiative effect from black carbon (BC) deposition to snow and sea ice. Here, we apply aerosol deposition fields from 25 models contributing to two phases of the Aerosol Comparisons between Observations and Models (AeroCom) project to simulate and evaluate within-snow BC concentrations and radiative effect in the Arctic. We accomplish this by driving the offline land and sea ice components of the Community Earth System Model with different deposition fields and meteorological conditions from 2004 to 2009, during which an extensive field campaign of BC measurements in Arctic snow occurred. We find that models generally underestimate BC concentrations in snow in northern Russia and Norway, while overestimating BC amounts elsewhere in the Arctic. Although simulated BC distributions in snow are poorly correlated with measurements, mean values are reasonable. The multi-model mean (range) bias in BC concentrations, sampled over the same grid cells, snow depths, and months of measurements, are −4.4 (−13.2 to +10.7) ng g−1 for an earlier phase of AeroCom models (phase I), and +4.1 (−13.0 to +21.4) ng g−1 for a more recent phase of AeroCom models (phase II), compared to the observational mean of 19.2 ng g−1. Factors determining model BC concentrations in Arctic snow include Arctic BC emissions, transport of extra-Arctic aerosols, precipitation, deposition efficiency of aerosols within the Arctic, and meltwater removal of particles in snow. Sensitivity studies show that the model–measurement evaluation is only weakly affected by meltwater scavenging efficiency because most measurements were conducted in non-melting snow. The Arctic (60–90° N) atmospheric residence time for BC in phase II models ranges from 3.7 to 23.2 days, implying large inter-model variation in local BC deposition efficiency. Combined with the fact that most Arctic BC deposition originates from extra-Arctic emissions, these results suggest that aerosol removal processes are a leading source of variation in model performance. The multi-model mean (full range) of Arctic radiative effect from BC in snow is 0.15 (0.07–0.25) W m−2 and 0.18 (0.06–0.28) W m−2 in phase I and phase II models, respectively. After correcting for model biases relative to observed BC concentrations in different regions of the Arctic, we obtain a multi-model mean Arctic radiative effect of 0.17 W m−2 for the combined AeroCom ensembles. Finally, there is a high correlation between modeled BC concentrations sampled over the observational sites and the Arctic as a whole, indicating that the field campaign provided a reasonable sample of the Arctic.

Final-revised paper