Air samples collected at Olympic Peninsula, USA.(48°N, 126°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 TTCM0034 11-JAN-88 1.77 -47.75 TTCM0035 29-MAR-88 1.76 -47.56 TTCM0036 3-APR-88 1.79 -47.69 TTCM0037 18-MAY-88 1.77 -47.64 TTCM0038 7-JUN-88 1.47 -47.41 TTCM0039 15-JUL-88 1.73 -47.51 TTCM0040 6-AUG-88 1.68 -47.60 TTCM0041 6-SEP-88 1.79 -47.85 TTCM0043 14-SEP-88 1.78 -47.83 TTCM0042 21-SEP-88 1.72 -47.71 TTCM0044 7-OCT-88 1.73 -47.37 TTCM0045 14-OCT-88 1.75 -47.61 TTCM0046 25-OCT-88 1.77 -47.61 TTCM0047 4-NOV-88 1.79 -47.76 TTCM0053 4-NOV-88 1.74 -47.75 TTCM0048 17-NOV-88 1.78 -47.67 TTCM0049 13-DEC-88 1.79 -47.60 TTCM0052 13-DEC-88 1.67 -47.56 TTCM0051 13-DEC-88 1.77 -47.63 TTCM0057 10-JAN-89 1.73 -47.59 TTCM0058 10-JAN-89 1.74 -47.51 TTCM0055 10-JAN-89 1.84 -47.68 TTCM0056 21-JAN-89 1.72 -47.54 TTCM0054 15-FEB-89 1.77 -47.65 TTCM0059 7-MAR-89 1.80 -47.60 TTCM0060 22-MAR-89 1.80 1.964 -47.51 TTCM0061 20-APR-89 1.79 1.758 -47.51 TTCM0063 6-JUN-89 1.75 1.734 -47.45 TTCM0064 7-JUN-89 1.74 1.745 -47.48 TTCMOO65 9-JUN-89 1.77 1.743 -47.38 TTCM0066 13-JUL-89 1.75 1.719 -47.31 TTCM0067 28-JUL-89 1.72 1.723 -47.44 TTCM0068 15-AUG-89 1.74 1.763 -47.27 TTCM0069 15-SEP-89 1.80 1.763 -47.78 TTCM0076 30-SEP-89 1.73 1.754 -47.74 TTCM0077 14-OCT-89 1.73 1.769 -47.81 TTCM0078 21-OCT-89 1.74 1.746 -47.61 TTCM0079 29-OCT-89 1.75 1.792 -47.59 TTCM0080 4-NOV-89 1.75 1.771 -47.67 TTCM0081 19-NOV-89 1.74 1.735 -47.57 TTCM0084 2-DEC-89 1.76 1.759 -47.48 TTCM0083 16-DEC-89 1.74 1.753 -47.40 TTCM0084A 13-JAN-90 1.77 1.776 -47.51 TTCM0085 27-JAN-90 1.76 1.759 -47.47 TTCM0089 3-MAR-90 1.73 1.764 -47.35 TTCM0093 22-MAR-90 1.75 1.782 -47.39 TTCM0092 22-MAR-90 1.77 1.782 -47.47 TTCM0088 23-MAR-90 1.78 1.784 -47.39 TTCM0091 7-APR-90 1.77 1.756 -47.40 TTCM0097 7-APR-90 1.79 1.756 -47.36 TTCM0096 7-APR-90 1.94 1.756 -47.42 TTCM0094 7-APR-90 1.80 1.756 -47.44 TTCM0098 7-APR-90 1.75 1.756 -47.38 TTCMO121 8-MAY-90 1.73 -47.39 TTCM0101 10-JUN-90 1.73 1.753 -47.52 TTCM0099 10-JUN-90 1.77 1.753 -47.35 TTCM0100 10-JUN-90 1.74 1.753 -47.48 TTCM0102 24-JUN-90 1.73 1.760 -47.55 TTCM0103 24-JUN-90 1.76 1.760 -47.47 TTCM0104 8-JUL-90 1.76 1.735 -47.32 TTCM0106 22-JUL-90 1.72 1.753 -47.52 TTCM0105 22-JUL-90 1.74 1.753 -47.56 TTCM0107 11-AUG-90 1.75 1.731 -47.48 TTCM0108 2-SEP-90 1.72 1.778 -47.94 TTCM0109 16-SEP-90 1.77 1.745 -47.77 TTCM0110 13-OCT-90 1.75 1.785 -47.74 TTCM0111 13-OCT-90 1.75 1.785 -47.86 TTCM0113 11-NOV-90 1.72 1.735 -47.39 TTCM0114 4-DEC-90 1.78 1.807 -47.74 TTCM0116 28-DEC-90 1.78 1.789 -47.67 TTCM0115 28-DEC-90 1.74 1.789 -47.64 TTCM0120 20-JAN-91 1.73 1.777 -47.63 TTCM0122 3-FEB-91 1.75 -47.67 TTCM0119 24-FEB-91 1.75 1.779 -47.24 TTCM0118 24-FEB-91 1.73 1.779 -47.54 TTCM0123 21-MAR-91 1.77 1.796 -47.73 TTCM0124 24-APR-91 1.74 1.765 -47.28 TTCM0125 15-MAY-91 1.76 1.779 -47.61 TTCM0127 31-MAY-91 1.74 1.783 -47.63 TTCM0128 26-JUN-91 1.72 1.760 -47.26 TTCM0129 21-JUL-91 1.72 1.709 -47.30 TTCM0130 13-AUG-91 1.80 -47.70 TTCM0132 9-SEP-91 1.75 1.782 -47.95 TTCM0133 11-OCT-91 1.70 1.741 -47.51 TTCM0134 31-OCT-91 1.80 1.823 -47.29 TTCM0136 31-OCT-91 1.79 1.882 -47.67 TTCM0137 31-OCT-91 1.85 1.823 -47.50 TTCM0139 2-DEC-91 1.79 1.790 -47.69 TTCM0138 2-DEC-91 1.80 1.790 -47.45 TTCM0142 18-JAN-92 1.79 1.795 -47.77 TTCM0141 18-JAN-92 1.78 1.795 -47.64 TTCM0140 18-JAN-92 1.78 1.795 -47.59 TTCM0144 5-FEB-92 1.76 1.794 -47.47 TTCM0145 5-FEB-92 1.83 1.794 -47.45 TTCM0146 5-FEB-92 1.84 1.794 -47.59 TTCM0151 5-MAR-92 1.85 1.786 -47.48 TTCM0150 5-MAR-92 1.83 1.786 -47.47 TTCM0148 11-APR-92 1.84 -47.25 TTCM0143 11-APR-92 1.97 -47.45 TTCM0149 11-APR-92 1.83 -47.25 TTCM0147 11-APR-92 1.83 -47.25 TTCM0153 15-MAY-92 1.82 1.782 -47.49 TTCM0152 15-MAY-92 1.79 1.782 -47.50 TTCM0155 14-JUN-92 1.77 1.732 -47.32 TTCM0154 14-JUN-92 1.67 1.732 -47.27 TTCM0156 12-JUL-92 1.80 1.743 -47.54 TTCM0157 12-JUL-92 1.80 1.743 -47.46 TTCM0159 30-JUL-92 1.77 -47.43 TTCM0158 30-JUL-92 1.80 -47.40 TTCM0162 2-SEP-92 1.80 1.766 -47.62 TTCM0164 4-OCT-92 1.79 -47.70 TTCM0163 4-OCT-92 1.84 -47.63 TTCM0165 4-OCT-92 1.81 -47.68 TTCM0166 8-NOV-92 1.81 1.778 -47.58 TTCM0170 28-NOV-92 1.82 1.782 -47.64 TTCM0169 28-NOV-92 1.81 1.782 -47.57 TTCM0172 20-DEC-92 1.83 1.785 -47.46 TTCM0171 20-DEC-92 1.81 1.785 -47.54 TTCM0173 6-FEB-93 1.84 1.787 -47.47 TTCM0174 6-FEB-93 1.80 1.787 -47.24 TTCM0175 27-FEB-93 1.86 1.793 -47.29 TTCM0176 27-FEB-93 1.81 1.793 -47.45 TTCM0177 13-MAR-93 1.78 1.780 -47.51 TTCM0178 13-MAR-93 1.82 1.780 -47.44 TTCM0179 28-MAR-93 1.83 1.790 -47.41 TTCM0182 1-MAY-93 1.82 1.783 -47.34 TTCM0180 1-MAY-93 1.84 1.783 -47.21 TTCM0183 1-MAY-93 1.82 1.783 -47.23 TTCM0184 1-MAY-93 1.87 1.783 -47.38 TTCM0181 1-MAY-93 1.81 1.783 -47.37 TTCM0187 14-MAY-93 1.77 1.779 -47.33 TTCM0188 14-MAY-93 1.79 1.779 -47.32 TTCM0186 13-JUN-93 1.83 1.782 -47.29 TTCM0189 8-JUL-93 1.79 -47.53 TTCM0192 17-AUG-93 1.75 1.732 -47.36 TTCM0191 17-AUG-93 1.76 1.732 -47.35 TTCM0190 31-AUG-93 1.83 1.787 -47.67 TTCM0194 29-OCT-93 1.79 1.796 -47.44 TTCM0193 29-OCT-93 1.85 1.796 -47.36 TTCM0211 6-NOV-93 1.88 -47.59 TTCM0210 6-NOV-93 1.86 -47.53 TTCM0209 6-NOV-93 1.86 -47.50 TTCM0195 20-NOV-93 1.81 1.789 -47.31 TTCM0196 20-NOV-93 1.82 1.789 -47.43 TTCM0199 1-DEC-93 1.86 1.800 -47.55 TTCM0197 1-DEC-93 1.81 1.800 -47.52 TTCM0198 1-DEC-93 1.82 1.800 -47.47 TTCM0200 11-DEC-93 1.71 -47.43 TTCM0201 11-DEC-93 1.79 -47.47 TTCM0206 11-DEC-93 1.81 -47.65 TTCM0205 11-DEC-93 1.77 -47.64 TTCM0202 31-DEC-93 1.79 -47.53 TTCM0203 31-DEC-93 1.81 -47.51 TTCM0204 31-DEC-93 1.83 -47.53 TTCM0207 10-JAN-94 1.79 1.775 -47.43 TTCM0212 9-FEB-94 1.80 1.803 -47.59 TTCM0213 9-FEB-94 1.83 1.803 -47.49 TTCM0216 22-FEB-94 1.78 -47.44 TTCM0215 22-FEB-94 1.76 -47.48 TTCM0214 22-FEB-94 1.97 -47.49 TTCM0218 17-MAR-94 1.72 -47.50 TTCM0232 28-MAR-94 1.82 -47.34 TTCM0219 31-MAR-94 1.73 -47.33 TTCM0220 31-MAR-94 1.71 -47.35 TTCM0221 19-APR-94 1.75 -47.47 TTCM0254 11-MAY-94 1.815 -47.29 TTCM0222 11-MAY-94 1.70 -47.27 TTCM0223 26-MAY-94 1.78 -47.45 TTCM0224 21-JUN-94 1.76 -47.44 TTCM0225 30-JUN-94 1.73 -47.41 TTCM0246 6-JUL-94 1.812 -47.33 TTCM0227 25-JUL-94 1.69 -47.41 TTCM0226 25-JUL-94 1.76 -47.39 TTCM0229 3-AUG-94 1.73 -47.24 TTCM0228 18-AUG-94 1.75 -47.37 TTCM0227A 18-AUG-94 1.81 -47.08 TTCM0231 13-SEP-94 1.71 -47.42 TTCM0230 13-SEP-94 1.80 -47.45 TTCM0234 30-SEP-94 1.84 -47.54 TTCM0233 30-SEP-94 1.79 -47.29 TTCM0237 20-OCT-94 1.75 -47.61 TTCM0236 20-OCT-94 1.82 -47.59 TTCM0235 4-NOV-94 1.81 -47.72 TTCM0238 16-NOV-94 1.77 -47.67 TTCM0252 31-JAN-95 1.793 -47.42 TTCM0250 15-FEB-95 1.821 -47.43 TTCMO248 15-FEB-95 1.855 -47.40 TTCM0249 15-FEB-95 1.843 -47.38 TTCM0256 14-MAR-95 1.775 -47.56 TTCM0257 1-APR-95 1.801 -47.47 TTCM0258 1-APR-95 1.773 -47.53 TTCM0263 26-MAY-95 1.775 -47.26 TTCM0262 13-JUN-95 1.787 -47.25 TTCM0264 23-JUN-95 1.830 -47.24 TTCM0266 3-JUL-95 1.780 -47.10 TTCM0267 3-JUL-95 1.707 -47.26 TTCM0268 3-JUL-95 1.687 -47.22 TTCM0269 21-JUL-95 1.743 -47.26 TTCM0270 21-JUL-95 1.752 -47.16 TTCM0271 8-AUG-95 -47.58 TTCM0272 5-SEP-95 1.763 -47.41 TTCM0273 5-SEP-95 1.757 -47.41 TTCM0279 27-SEP-95 1.935 -47.62 TTCM0281 12-OCT-95 1.785 -47.72 TTCM0282 12-OCT-95 1.777 -47.66 TTCM0283 25-OCT-95 1.899 -47.62 TTCM0284 25-OCT-95 1.903 -47.63 TTCM0285 7-NOV-95 1.742 -47.55 TTCM0286 7-NOV-95 1.781 -47.51 TTCM0287 30-NOV-95 1.922 -47.62 TTCM0288 30-NOV-95 1.873 -47.56 TTCM0289 18-DEC-95 1.896 -47.48 TTCM0290 18-DEC-95 1.871 -47.38 TTCM0291 2-JAN-96 1.750 -47.54 TTCM0292 2-JAN-96 1.731 -47.47 TTCM0293 23-JAN-96 1.886 -47.38 TTCM0294 23-JAN-96 1.878 -47.46 TTCM0296 3-MAR-96 1.862 -47.36 TTCM0297 19-MAR-96 1.818 -47.42 TTCM0298 19-MAR-96 1.833 -47.42 TTCM0299 1-MAY-96 1.824 -47.38 TTCM0300 24-APR-96 1.829 -47.41 TTCM0301 1-MAY-96 1.762 -47.42 TTCM0302 1-MAY-96 1.757 -47.38 TTCM0303 24-APR-96 1.777 -47.47 TTCM0304 24-APR-96 1.762 -47.47 (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).