Quasi-Continuous Methane Measurements at Cherskii, Russia
M.J. Heller1, A.M. Crotwell1, S.A. Zimov2, N.S. Zimov2, M. Iliasov2, G. Pétron1, L. Bruhwiler3, J.B. Miller3, M.S. Bret-Harte4, C. Edgar4 and E.J. Dlugokencky3
1Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309; 303-497-4728, E-mail: Molly.Heller@noaa.gov
2Northeast Science Station, Russian Academy of Sciences, Cherskii, Russia
3NOAA Earth System Research Laboratory, Boulder, CO 80305
4Institute of Arctic Biology, University of Alaska, Fairbanks, AK 99775-7000
Atmospheric methane (CH4) mixing ratio has been measured quasi-continuously at Cherskii, Russia (68°30’N, 161°32’E) since September 2008. Samples are taken approximately every 5 minutes rotating between three different tower levels (2.6 m, 16.2 m, and 34.4 m). Measurements are made using an optical analyzer that uses off-axis, integrated cavity output spectroscopy, a robust measurement technique for remote sites. The uncertainty at 68% confidence limit is ± 2.4 ppb. The average seasonal cycle peak-to-peak amplitude at Cherskii is 33.4 ppb with a minimum in late spring and a maximum in late winter. A significant diurnal cycle is not observed throughout the year. Figure 1 shows CH4 data from Cherskii plotted with a marine boundary layer reference for 72.8° N and ~ weekly discreet samples from five arctic sites. CH4 data at Cherskii are highly variable with large enhancements especially after periods of low wind speed in the summer, when wetland emissions are greatest.
Figure 1. CH4 mole fraction (ppb = nmol mol-1) from Cherskii, Russia (CHS) plotted with the marine boundary layer reference (MBL reference) for 72.8° N and discreet samples from Summit, Greenland (SUM); Alert, Canada (ALT); Pallas-Sammaltunturi, Finland (PAL); Ny-Ålesund, Svalbard, Norway and Sweden (ZEP), and Barrow, Alaska, United States (BRW).