Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Atmos. Chem. Phys., 14, 2399-2417, 2014
http://www.atmos-chem-phys.net/14/2399/2014/
doi:10.5194/acp-14-2399-2014
© Author(s) 2014. This work is distributed
under the Creative Commons Attribution 3.0 License.
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 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.

Citation: Jiao, C., Flanner, M. G., Balkanski, Y., Bauer, S. E., Bellouin, N., Berntsen, T. K., Bian, H., Carslaw, K. S., Chin, M., De Luca, N., Diehl, T., Ghan, S. J., Iversen, T., Kirkevåg, A., Koch, D., Liu, X., Mann, G. W., Penner, J. E., Pitari, G., Schulz, M., Seland, Ø., Skeie, R. B., Steenrod, S. D., Stier, P., Takemura, T., Tsigaridis, K., van Noije, T., Yun, Y., and Zhang, K.: An AeroCom assessment of black carbon in Arctic snow and sea ice, Atmos. Chem. Phys., 14, 2399-2417, doi:10.5194/acp-14-2399-2014, 2014.
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