Supplement of Atmospheric constraints on the methane emissions ...

Supplement of Atmos. Chem. Phys., 16, 4147–4157, 2016http://www.atmos-chem-phys.net/16/4147/2016/doi:10.5194/acp-16-4147-2016-supplement© Author(s) 2016. CC Attribution 3.0 License.

Supplement of

Atmospheric constraints on the methane emissions from theEast Siberian Shelf

Antoine Berchet et al.

Correspondence to:Antoine Berchet ([email protected])

The copyright of individual parts of the supplement might differ from the CC-BY 3.0 licence.

Footprint analysis

The influence of every methane emission contribution (anthropogenic, wetlands, ESAS) is explicitlycomputed with the model CHIMERE at the observation sites for every hour of the year 2012. How-ever, as a visualisation tool, we show here some monthly footprints by observation site to display theregions influencing the most each observation site depending on meteorological conditions.

The footprints are computed with the Lagrangian dispersion model FLEXPART version 8.2.3(Stohl et al., 2005). We compute numerous back-trajectories of virtual particles from the observationsites for every hour of the period of interest. The footprints are computed on a 0.5◦×0.5◦ horizontalgrid, following the method of Lin et al. (2003). The model is forced by ECMWF ERA-Interim dataat an horizontal resolution of 1◦×1◦, with 60 vertical levels and 3 hours temporal resolution (Uppalaet al., 2005). Virtual particles with 10-day lifetime backwards in time are released in a 3D box (10 kmper side and 500 m high) centered around each observation site.

Figs. S1, S2, S3, S4 and S5 show these footprints for each observation site. TIK site is shown to beinfluenced mainly by ESAS and by regional wetlands (in the Lena delta and along the shores betweenLena and Indigirka rivers), but also by the Lena river basin and by emissions along the North Siberianshores. Depending on the wind regime, BRW can be either influenced by North American sources,or by ESAS emissions. ALT is shown to be mainly influenced by North American emissions, buttransport from ESAS across the Arctic ocean is also exhibited by the footprints (e.g., especially inFebruary and March).

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January February March

April May June

July August September

October November December

Figure S1. Footprint at TIK site by month of year 2012 (arbitrary unit).

2

January February March

April May June

July August September

October November December

Figure S2. Footprint at BRW site by month of year 2012 (arbitrary unit).

3

January February March

April May June

July August September

October November December

Figure S3. Footprint at ALT site by month of year 2012 (arbitrary unit).

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January February March

April May June

July August September

October November December

Figure S4. Footprint at PAL site by month of year 2012 (arbitrary unit).

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January February March

April May June

July August September

October November December

Figure S5. Footprint at ZEP site by month of year 2012 (arbitrary unit).

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References

Lin, J. C., Gerbig, C., Wofsy, S. C., Andrews, A. E., Daube, B. C., Davis, K. J., and Grainger, C. A.:A near-field tool for simulating the upstream influence of atmospheric observations: The StochasticTime-Inverted Lagrangian Transport (STILT) model, Journal of Geophysical Research: Atmospheres, 108,doi:10.1029/2002JD003161, http://onlinelibrary.wiley.com/doi/10.1029/2002JD003161/abstract, 2003.

Stohl, A., Forster, C., Frank, A., Seibert, P., Wotawa, G., et al.: Technical note: The Lagrangian particle disper-sion model FLEXPART version 6.2, Atmos. Chem. Phys., 5, 2461–2474, http://hal-insu.archives-ouvertes.fr/hal-00301615/, 2005.

Uppala, S. M., Kållberg, P. W., Simmons, A. J., Andrae, U., Bechtold, V. D. C., Fiorino, M., Gibson, J. K.,Haseler, J., Hernandez, A., Kelly, G. A., Li, X., Onogi, K., Saarinen, S., Sokka, N., Allan, R. P., Anders-son, E., Arpe, K., Balmaseda, M. A., Beljaars, A. C. M., Berg, L. V. D., Bidlot, J., Bormann, N., Caires,S., Chevallier, F., Dethof, A., Dragosavac, M., Fisher, M., Fuentes, M., Hagemann, S., Hólm, E., Hoskins,B. J., Isaksen, L., Janssen, P. a. E. M., Jenne, R., Mcnally, A. P., Mahfouf, J.-F., Morcrette, J.-J., Rayner,N. A., Saunders, R. W., Simon, P., Sterl, A., Trenberth, K. E., Untch, A., Vasiljevic, D., Viterbo, P., andWoollen, J.: The ERA-40 re-analysis, Quarterly Journal of the Royal Meteorological Society, 131, 2961–3012, doi:10.1256/qj.04.176, http://onlinelibrary.wiley.com/doi/10.1256/qj.04.176/abstract, 2005.

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