Air samples collected at Cape Matatula, American Samoa.(14°S, 171°W) 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-CMDL Methane concentration (ppm) determined by gas chromatography by NOAA/CMDL laboratory with precsion of ±0.2%, see Dlugokencky 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-CMDL Del 13C TTOM0001 15-DEC-89 1.66 1.964 -47.34 TTOM0002 28-DEC-89 1.64 1.634 -47.24 TTOM0003 11-JAN-90 1.70 1.642 -47.21 TTOM0004 27-JAN-90 1.66 1.626 -47.22 TTOM0005 2-MAR-90 1.70 -47.15 TTOM0008 29-MAR-90 1.65 -47.18 TTOM0012 27-APR-90 1.63 1.638 -47.32 TTOM0011 27-APR-90 1.66 1.638 -47.05 TTOM0016 11-MAY-90 1.67 1.633 -47.30 TTOM0015 11-MAY-90 1.70 1.633 -47.33 TTOM0018 11-MAY-90 1.68 1.633 -47.29 TTOM0013 25-MAY-90 1.64 1.640 -47.30 TTOM0014 25-MAY-90 1.66 1.640 -47.16 TTOM0017 7-JUN-90 1.64 1.646 -47.27 TTOM0020 7-JUN-90 1.65 1.646 -47.24 TTOM0019 7-JUN-90 1.63 1.646 -47.29 TTOM0022 22-JUN-90 1.68 1.652 -47.18 TTOM0021 22-JUN-90 1.61 1.652 -47.18 TTOM0025 6-JUL-90 1.66 1.650 -47.41 TTOM0023 6-JUL-90 1.66 1.650 -47.32 TTOM0024 20-JUL-90 1.68 1.657 -47.28 TTOM0027 2-AUG-90 1.67 1.665 -47.20 TTOM0026 2-AUG-90 1.64 1.665 -47.06 TTOM0029 16-AUG-90 1.69 1.656 -47.31 TTOM0028 16-AUG-90 1.68 1.656 -47.27 TTOM0033 30-AUG-90 1.68 1.664 -47.33 TTOM0030 13-SEP-90 1.72 1.649 -47.25 TTOM0031 28-SEP-90 1.66 1.662 -47.30 TTOM0034 11-OCT-90 1.68 1.648 -47.24 TTOM0035 30-OCT-90 1.66 1.647 -47.29 TTOM0037 9-NOV-90 1.66 1.653 -47.20 TTOM0036 9-NOV-90 1.65 1.653 -47.26 TTOM0039 23-NOV-90 1.69 1.662 -47.25 TTOM0038 23-NOV-90 1.68 1.662 -47.35 TTOM0042 6-DEC-90 1.67 1.644 -47.32 TTOM0041 6-DEC-90 1.67 1.644 -47.20 TTOM0040 24-DEC-90 1.67 1.681 -47.48 TTOM0043 4-JAN-91 1.67 1.680 -47.33 TTOM0045 18-JAN-91 1.67 1.664 -47.60 TTOM0046 12-FEB-91 1.64 1.651 -47.36 TTOM0047 28-FEB-91 1.67 1.690 -47.33 TTOM0048 14-MAR-91 1.64 1.650 -47.37 TTOM0049 26-MAR-91 1.64 1.654 -47.32 TTOM0050 9-APR-91 1.64 1.639 -47.41 TTOM0053 4-JUN-91 1.70 1.654 -47.37 TTOM0058 19-JUN-91 1.68 1.705 -47.37 TTOM0056 10-JUL-91 1.68 1.685 -47.05 TTOM0057 21-AUG-91 1.66 -47.23 TTOM0060 23-SEP-91 1.68 1.679 -47.25 TTOM0063 22-OCT-91 1.67 1.666 -47.03 TTOM0066 19-NOV-91 1.69 1.664 -47.25 TTOM0065 3-DEC-91 1.71 1.663 -47.30 TTOM0064 3-DEC-91 1.68 1.663 -47.13 TTOM0069 23-JAN-92 1.65 1.657 -47.35 TTOM0072 10-MAR-92 1.79 1.697 -47.18 TTOM0078 6-APR-92 1.67 1.651 -46.91 TTOM0079 6-APR-92 1.72 1.651 -47.17 TTOM0073 27-MAY-92 1.73 1.669 -47.36 TTOM0072A 27-MAY-92 1.69 1.669 -47.52 TTOM0075 6-JUL-92 1.72 1.674 -47.30 TTOM0074 6-JUL-92 1.72 1.674 -47.29 TTOM0076 27-JUL-92 1.77 1.674 -47.31 TTOM0077 27-JUL-92 1.74 1.674 -47.38 TTOM0081 25-AUG-92 1.68 1.675 -47.09 TTOM0083 8-SEP-92 1.72 1.670 -47.44 TTOM0082 8-SEP-92 1.60 1.670 -47.13 TTOM0086 28-SEP-92 1.68 1.672 -47.24 TTOM0085 28-SEP-92 1.73 1.672 -47.19 TTOM0084 28-SEP-92 1.78 1.672 -47.10 TTOM0087 16-NOV-92 1.72 1.665 -47.25 TTOM0089 16-NOV-92 1.68 1.665 -46.95 TTOM0088 16-NOV-92 1.75 1.665 -47.30 TTOM0095 2-DEC-92 1.78 1.667 -47.27 TTOM0094 2-DEC-92 1.71 1.667 -47.15 TTOM0091 14-DEC-92 1.75 1.659 -47.15 TTOM0090 14-DEC-92 1.70 1.659 -47.19 TTOM0093 31-DEC-92 1.73 1.659 -47.12 TTOM0099 14-JAN-93 1.70 1.668 -47.46 TTOM0098 14-JAN-93 1.77 1.668 -47.29 TTOM0100 4-FEB-93 1.71 1.683 -47.22 TTOM0102 25-MAR-93 1.71 1.668 -47.29 TTOM0101 25-MAR-93 1.78 1.668 -47.15 TTOM0107 20-APR-93 1.72 1.671 -47.29 TTOM0108 20-APR-93 1.76 1.671 -47.23 TTOM0103 5-MAY-93 1.75 1.666 -47.17 TTOM0106 31-MAY-93 1.72 1.666 -47.15 TTOM0105 31-MAY-93 1.74 1.666 -47.11 TTOM0109 21-JUN-93 1.74 -47.25 TTOM0113 27-JUL-93 1.74 1.689 -47.39 TTOM0112 27-JUL-93 1.73 1.689 -47.40 TTOM0110 9-AUG-93 1.74 1.677 -47.29 TTOM0111 9-AUG-93 1.75 1.677 -47.19 TTOM0110A 18-AUG-93 1.72 -47.47 TTOM0114 30-AUG-93 1.72 1.684 -47.39 TTOM0118 26-OCT-93 1.77 1.673 -47.18 TTOM0117 26-OCT-93 1.74 1.673 -47.12 TTOM0126 9-NOV-93 1.77 -47.11 TTOM0119 15-DEC-93 1.75 -47.11 TTOM0120 15-DEC-93 1.75 -47.20 TTOM0122 27-DEC-93 1.72 1.684 -46.94 TTOM0121 27-DEC-93 1.76 1.684 -47.04 TTOM0123 20-JAN-94 1.72 1.664 -47.29 TTOM0124 20-JAN-94 1.76 1.664 -46.93 TTOM0129 1-APR-94 1.73 -47.30 TTOM0128 5-APR-94 1.78 -47.23 TTOM0127 5-APR-94 1.77 -47.31 TTOM0133 5-MAY-94 1.71 -47.15 TTOM0132 5-MAY-94 1.72 -47.23 TTOM0131 17-MAY-94 1.75 -47.19 TTOM0130 17-MAY-94 1.76 -47.06 TTOM0135 1-JUN-94 1.75 -47.25 TTOM0134 1-JUN-94 1.79 -47.22 TTOM0136 21-JUN-94 1.77 -47.28 TTOM0149 27-JUL-94 1.79 -47.26 TTOM0141 23-AUG-94 1.80 -47.33 TTOM0142 15-SEP-94 1.71 -47.19 TTOM0145 20-OCT-94 1.76 -47.18 TTOM0146 20-OCT-94 1.77 -47.11 TTOM0147 2-NOV-94 1.74 -47.17 TTOM0148 23-NOV-94 1.78 -47.23 TTOM0151 12-DEC-94 1.80 -47.14 TTOM0155 22-FEB-95 1.75 -47.13 TTOM0154 2-MAR-95 1.76 -47.06 TTOM0157 22-MAR-95 1.79 -47.09 TTOM0163 8-MAY-95 1.73 -47.11 TTOM0162 8-MAY-95 1.84 -47.21 TTOM0160 23-MAY-95 1.70 -47.29 TTOM0159 23-MAY-95 1.73 -47.25 TTOM0161 7-JUN-95 1.24 -47.17 TTOM0165 5-JUL-95 1.74 -47.20 TTOM0164 5-JUL-95 1.81 -47.26 TTOM0167 21-JUL-95 1.53 -47.13 TTOM0166 2-AUG-95 1.72 -47.14 TTOM0169 29-AUG-95 1.64 -47.14 TTOM0170 11-SEP-95 1.75 -47.01 TTOM0171 8-NOV-95 1.74 -47.14 TTOM0172 22-NOV-95 1.76 -47.42 TTOM0173 26-DEC-95 1.72 -47.14 TTOM0174 26-DEC-95 1.54 -47.12 TTOM0175 8-JAN-96 1.73 -47.12 TTOM0176 8-JAN-96 1.70 -47.10 TTOM0177 24-JAN-96 1.71 -47.16 TTOM0178 21-FEB-96 1.74 -47.36 TTOM0179 21-FEB-96 1.68 -47.38 TTOM0181 21-MAR-96 1.73 -47.40 TTOM0182 21-MAR-96 1.70 -47.53 TTOM0183 15-APR-96 1.71 -46.94 (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) DLUGOKENCKY, E.J., K.A. MASARIE, P.M. LANG, P.P. TANS, L.P. Steele, and E.G. Nisbet. A dramatic decrease in the growth rate of atmospheric methane in the northern hemisphere during 1992. Geophysical Research Letters 20(1):45-48 (1994).