Air samples collected at Baring Head, New Zealand.(41S,177E) SIL ID # Identification Number used at the Stable Isotope Lab, University of Washington. Date Date that this sample was collected. CH4-SIL Methane concentration (ppm) determined manometrically at SIL with precision of ± 2%, see Quay et al. (1). CH4-NIWAR Methane concentration (ppm) determined by gas chromatography by NIWAR, see Lowe et al. (2). Del 13C Measured 13C/12C in per mil (0/00) units, where del 13C(0/00) ={[(13C/12C)sample/(13C/12C)standard - 1]*1000} and the standard is VPDB, see Quay et al. (1). Del 13C (0/00) corrected for standard drift, see Quay et al. (1). SIL ID # Date CH4-SIL CH4-NIWAR Del 13C TTZM0001 25-FEB-91 1.58 1.660 -47.02 TTZM0003 25-FEB-91 1.59 1.660 -46.95 TTZM0002 25-FEB-91 1.57 1.660 -47.27 TTZM0005 4-MAR-91 1.62 1.669 -47.48 TTZM0004 4-MAR-91 1.63 1.669 -47.30 TTZM0007 20-JUN-91 1.63 1.683 -47.09 TTZM0010 26-AUG-91 1.65 1.707 -47.36 TTZM0009 26-AUG-91 1.64 1.707 -47.35 TTZM0012 7-SEP-91 1.69 1.704 -47.12 TTZM0011 7-SEP-91 1.66 1.704 -47.22 TTZM0013 24-OCT-91 1.65 1.697 -47.42 TTZM0015 24-OCT-91 1.72 1.697 -47.40 TTZM0016 24-OCT-91 1.65 1.697 -47.42 TTZM0014 24-OCT-91 1.63 1.697 -47.23 TTZM0023 29-NOV-91 1.74 1.691 -47.24 TTZM0021 29-NOV-91 1.73 1.691 -47.31 TTZM0020 29-NOV-91 1.74 1.691 -47.31 TTZM0022 29-NOV-91 1.69 1.691 -47.39 TTZM0018 28-FEB-92 1.69 1.678 -46.93 TTZM0017 28-FEB-92 1.68 1.678 -46.98 TTZM0024 7-MAY-92 1.73 1.684 -47.26 TTZM0026 7-MAY-92 1.71 1.684 -47.41 TTZM0027 7-MAY-92 1.68 1.684 -47.43 TTZM0028 22-MAY-92 1.69 1.689 -47.17 TTZM0030 22-MAY-92 1.69 1.689 -46.99 TTZM0029 22-MAY-92 1.69 1.689 -47.10 TTZM0033 15-JUL-92 1.66 1.705 -47.33 TTZM0031 15-JUL-92 1.70 1.705 -47.22 TTZM0034 29-AUG-92 1.75 1.707 -47.33 TTZM0035 29-AUG-92 1.70 1.707 -47.02 TTZM0036 29-AUG-92 1.69 1.707 -47.22 TTZM0037 29-AUG-92 1.69 1.707 -47.25 TTZM0039 16-SEP-92 1.69 1.704 -47.29 TTZM0040 16-SEP-92 1.72 1.704 -47.32 TTZM0038 16-SEP-92 1.73 1.704 -47.29 TTZM0042 10-DEC-92 1.66 1.694 -47.26 TTZM0041 10-DEC-92 1.70 1.694 -47.14 TTZM0044 10-DEC-92 1.68 1.694 -47.30 TTZM0043 10-DEC-92 1.68 1.694 -47.14 TTZM0047 13-JAN-93 1.70 1.684 -47.17 TTZM0045 13-JAN-93 1.72 1.684 -47.25 TTZM0046 13-JAN-93 1.67 1.684 -47.23 TTZM0049 15-FEB-93 1.66 1.676 -47.24 TTZM0047A 15-FEB-93 1.66 1.676 -47.07 TTZM0048 15-FEB-93 1.70 1.676 -47.26 TTZM0051 7-MAY-93 1.70 -47.24 TTZM0050 7-MAY-93 1.74 -47.28 TTZM0056 30-JUL-93 1.69 -47.33 TTZM0055 30-JUL-93 1.71 -47.30 TTZM0057 30-JUL-93 1.70 -47.34 TTZM0053 27-AUG-93 1.72 -47.21 TTZM0052 27-AUG-93 1.71 -47.30 TTZM0058 16-APR-94 1.72 1.688 -47.12 TTZM0060 7-JUL-94 1.74 1.702 -47.35 TTZM0059 15-NOV-94 1.72 1.711 -47.20 TTZM0061 15-NOV-94 1.73 1.711 -47.27 TTZM0060 15-NOV-94 1.73 1.711 -46.98 TTZM0065 13-FEB-95 1.68 1.688 -47.20 TTZM0064 13-FEB-95 1.70 1.688 -47.11 TTZM0068 28-APR-95 1.70 1.695 -47.05 TTZM0069 28-APR-95 1.70 1.695 -47.12 TTZM0066 23-MAY-95 1.70 1.715 -47.20 TTZM0070 2-AUG-95 1.76 1.689 -47.12 TTZM0071 2-AUG-95 1.71 1.689 -46.89 (1) Quay, P.D., J. Stutsman, D. Wilbur, A. Snover, E. Dlugokenky and T. Brown, (submitted), Isotopic Composition of Atmospheric Methane, Global Biogeochemical Cycles. (2) Lowe, D. C., Brenninkmeijer, C. A. M., Brailsford, G. W., Lassey, K. R., Gomez, A. J., and Nisbet, E. G., Concentration and 13C records of atmospheric methane in New Zealand and Antarctica: Evidence for changes in methane sources, J. Geophys. Res., 99, 16913-16925, 1994