# file: mhd_CCl4_MM.dat # # Atmospheric measurements of CCl4 (Carbon Tetrachloride, CT) # # Measurements are from the NOAA/ESRL/GMD/HATS flask program # (http://www.esrl.noaa.gov/gmd/hats/flask/flasks.html). # Instrument ID: Otto # # Location: MHD -- Mace Head, Ireland -- 53.33 N, 9.90 W, 25 m Elev. # See http://www.esrl.noaa.gov/gmd/dv/site/site_table.html#hats_flask for # more information about flask sampling sites. # # The data reported are from samples collected approximately once per week in # matching, concurrent, flask pairs and later analyzed on a gas chromatograph # with electron capture detection (GC-ECD) located in Boulder, Colorado, USA. # This system uses two standard reference gases for calibration and has been # in operation since very early in 1995. # # CCl4 loss during storage in stainless-steel canisters arises most commonly at # high-latitude and/or high-altitude sites where the air is dry (i.e. ALT, BRW, # MLO, NWR, and SPO -- especially in winter). Extra efforts have been made to # flag samples suspected of suffering from this known artifact, thereby barring # them from inclusion in monthly mean estimates. The user is cautioned, # however, that small biases to the low side may nevertheless remain. # # These data represent monthly mean estimates computed using those data marked # with a 0 in flag column 7 of the companion file named "mhd_CCl4_All.dat". With # flask samples collected only weekly on average, monthly sampling statistics # are poor at best. As a result, the error reported is either the standard # deviation of the mean or a floor single-sample precision estimate. # # PIs: Dr. James W. Elkins, Dr. Bradley D. Hall, # Debra J. Mondeel, J. David Nance # # National Oceanic and Atmospheric Administration (NOAA) # Earth System Research Laboratory (ESRL) # 325 Broadway, R/GMD1 # Boulder, CO 80305-3328 # # Email: James.W.Elkins@noaa.gov; Bradley.Hall@noaa.gov # Phone: (303) 497-6224 (303) 497-7011 # # Email: Debra.J.Mondeel@noaa.gov; David.Nance@noaa.gov # Phone: (303) 497-6013 (303) 497-7002 # # Fax: (303) 497-6290 # # Data use policy: # If you use this data in a publication or report, we would appreciate that you # contact the principal investigators (PIs) first and discuss your interests. # The PIs can discuss the quality of the data and any potential problems with # its analysis. Please contact the PIs for more information. The data should # be cited in presentations or publications along the following lines: Carbon Tetrachloride # data from the NOAA/ESRL halocarbons flask program. # # Calibration scale: NOAA 2008 # See http://www.esrl.noaa.gov/gmd/ccl/scales.html for more information about # calibration scales. # # Units: ppt # # Missing value: "nan" # # Data Columns: # yr Year # mon Month # m Monthly mean concentration of CCl4 in ppt # sd Standard deviation of the mean (or single-sample precision value) # n Number of samples # CCl4ottoMHDyr CCl4ottoMHDmon CCl4ottoMHDm CCl4ottoMHDsd CCl4ottoMHDn 1998 1 nan nan 0 1998 2 nan nan 0 1998 3 nan nan 0 1998 4 nan nan 0 1998 5 nan nan 0 1998 6 nan nan 0 1998 7 nan nan 0 1998 8 nan nan 0 1998 9 nan nan 0 1998 10 nan nan 0 1998 11 103.340 0.239 1 1998 12 102.900 0.220 1 1999 1 102.860 0.234 1 1999 2 102.300 0.153 1 1999 3 nan nan 0 1999 4 102.860 0.246 1 1999 5 nan nan 0 1999 6 102.060 0.324 1 1999 7 101.635 0.198 2 1999 8 nan nan 0 1999 9 nan nan 0 1999 10 nan nan 0 1999 11 nan nan 0 1999 12 nan nan 0 2000 1 nan nan 0 2000 2 nan nan 0 2000 3 nan nan 0 2000 4 nan nan 0 2000 5 nan nan 0 2000 6 nan nan 0 2000 7 nan nan 0 2000 8 nan nan 0 2000 9 nan nan 0 2000 10 nan nan 0 2000 11 nan nan 0 2000 12 nan nan 0 2001 1 nan nan 0 2001 2 nan nan 0 2001 3 nan nan 0 2001 4 nan nan 0 2001 5 100.350 0.628 1 2001 6 nan nan 0 2001 7 99.460 0.251 1 2001 8 99.626 0.368 2 2001 9 99.690 0.373 2 2001 10 nan nan 0 2001 11 nan nan 0 2001 12 nan nan 0 2002 1 nan nan 0 2002 2 99.038 0.115 2 2002 3 99.080 0.337 1 2002 4 98.862 0.187 2 2002 5 nan nan 0 2002 6 nan nan 0 2002 7 nan nan 0 2002 8 nan nan 0 2002 9 98.080 0.192 1 2002 10 98.170 0.204 1 2002 11 98.466 0.309 2 2002 12 98.560 0.266 1 2003 1 97.697 0.346 2 2003 2 97.527 0.175 2 2003 3 97.748 0.429 3 2003 4 97.240 0.240 1 2003 5 97.320 0.147 2 2003 6 97.283 0.223 2 2003 7 97.290 0.155 1 2003 8 97.090 0.229 1 2003 9 97.029 0.237 3 2003 10 97.000 0.633 1 2003 11 96.812 0.186 3 2003 12 97.050 0.244 1 2004 1 96.625 0.145 2 2004 2 96.605 0.277 2 2004 3 96.168 0.208 2 2004 4 96.270 0.157 2 2004 5 96.407 0.141 2 2004 6 96.442 0.173 2 2004 7 96.570 0.234 2 2004 8 96.151 0.194 2 2004 9 96.152 0.202 2 2004 10 95.890 0.244 1 2004 11 95.753 0.397 2 2004 12 95.744 0.186 2 2005 1 95.953 0.226 2 2005 2 95.568 0.163 2 2005 3 95.420 0.238 1 2005 4 95.838 0.332 2 2005 5 95.683 0.166 3 2005 6 95.370 0.238 1 2005 7 95.303 0.205 2 2005 8 94.910 0.162 2 2005 9 94.716 0.232 2 2005 10 94.882 0.175 3 2005 11 95.085 0.219 2 2005 12 94.750 0.250 1 2006 1 94.590 0.165 1 2006 2 94.120 0.375 1 2006 3 94.220 0.168 1 2006 4 94.173 0.168 3 2006 5 94.379 0.226 2 2006 6 94.034 0.276 2 2006 7 93.824 0.269 2 2006 8 93.790 0.269 2 2006 9 93.535 0.154 2 2006 10 93.451 0.193 2 2006 11 93.548 0.144 2 2006 12 93.262 0.208 2 2007 1 93.620 0.146 1 2007 2 92.921 0.337 2 2007 3 92.983 0.315 2 2007 4 92.718 0.205 2 2007 5 93.038 0.195 2 2007 6 92.737 0.443 2 2007 7 92.891 0.337 2 2007 8 92.790 0.352 1 2007 9 92.794 0.235 2 2007 10 92.186 0.297 2 2007 11 92.380 0.523 2 2007 12 92.104 0.286 2 2008 1 92.016 0.168 2 2008 2 91.744 0.283 2 2008 3 91.461 0.252 2 2008 4 91.590 0.277 1 2008 5 nan nan 0 2008 6 91.317 0.329 3 2008 7 90.780 0.254 3 2008 8 90.770 0.207 1 2008 9 90.360 0.266 1 2008 10 90.609 0.182 2 2008 11 90.614 0.416 2 2008 12 90.372 0.230 2 2009 1 90.205 0.395 2 2009 2 90.057 0.275 2 2009 3 90.081 0.232 2 2009 4 89.836 0.216 3 2009 5 89.868 0.332 2 2009 6 nan nan 0 2009 7 89.478 0.260 2 2009 8 89.826 0.297 2 2009 9 89.587 0.218 2 2009 10 nan nan 0 2009 11 89.809 0.318 2 2009 12 89.680 0.321 1 2010 1 89.611 0.229 2 2010 2 89.290 0.361 2 2010 3 89.118 0.353 2 2010 4 89.293 0.219 2 2010 5 89.213 0.211 2 2010 6 88.572 0.158 2 2010 7 88.841 0.162 2 2010 8 88.771 0.170 2 2010 9 88.695 0.110 2 2010 10 88.640 0.267 1 2010 11 88.478 0.271 2 2010 12 88.459 0.262 2 2011 1 88.478 0.242 2 2011 2 88.038 0.261 2 2011 3 88.145 0.369 2 2011 4 87.850 0.139 2 2011 5 87.722 0.127 2 2011 6 87.654 0.163 2 2011 7 87.329 0.156 2 2011 8 87.403 0.203 2 2011 9 87.185 0.220 2 2011 10 87.313 0.223 2 2011 11 87.439 0.148 2 2011 12 87.272 0.323 2 2012 1 86.670 0.151 1 2012 2 86.616 0.226 2 2012 3 nan nan 0 2012 4 86.380 0.291 1 2012 5 86.587 0.204 2 2012 6 nan nan 0 2012 7 86.240 0.283 1 2012 8 86.136 0.149 2 2012 9 86.190 0.135 1 2012 10 86.113 0.290 2 2012 11 85.700 0.375 1 2012 12 86.024 0.239 2 2013 1 85.820 0.203 2 2013 2 85.620 0.255 1 2013 3 85.590 0.131 1 2013 4 85.446 0.361 2 2013 5 85.626 0.530 2 2013 6 nan nan 0 2013 7 nan nan 0 2013 8 85.170 0.307 1 2013 9 nan nan 0 2013 10 nan nan 0 2013 11 84.670 1.818 2 2013 12 85.077 0.213 2 2014 1 nan nan 0 2014 2 nan nan 0 2014 3 84.710 0.600 1 2014 4 nan nan 0 2014 5 nan nan 0 2014 6 nan nan 0 2014 7 84.627 0.272 2 2014 8 84.536 0.153 2 2014 9 84.200 0.156 1 2014 10 84.233 0.368 2 2014 11 84.174 0.346 2 2014 12 83.706 0.186 2 2015 1 84.320 0.488 2 2015 2 84.174 0.252 2 2015 3 nan nan 0 2015 4 83.170 0.404 1 2015 5 82.936 0.241 2 2015 6 83.203 0.172 2 2015 7 83.201 0.247 2 2015 8 83.200 0.156 2 2015 9 83.210 0.302 1 2015 10 83.092 0.219 2 2015 11 82.772 0.202 2 2015 12 82.960 0.271 1 2016 1 82.219 0.370 2 2016 2 82.620 0.359 1 2016 3 82.070 0.315 1 2016 4 81.753 0.465 2 2016 5 82.410 0.568 2 2016 6 82.070 0.740 1 2016 7 81.882 0.324 2 2016 8 81.500 0.562 1 2016 9 81.779 0.225 2 2016 10 82.150 0.324 1 2016 11 81.942 0.326 2 2016 12 82.044 0.406 2 2017 1 81.671 0.820 2 2017 2 nan nan 0 2017 3 81.141 0.446 2 2017 4 80.730 0.512 1 2017 5 80.890 0.326 1 2017 6 81.280 0.375 1 2017 7 80.534 0.282 2 2017 8 81.030 0.448 1 2017 9 80.620 0.362 1 2017 10 81.138 0.232 2 2017 11 80.460 0.284 2 2017 12 81.020 0.643 2 2018 1 80.156 0.323 2 2018 2 79.937 0.384 2 2018 3 79.277 0.337 2 2018 4 79.841 0.250 3 2018 5 80.630 0.243 1 2018 6 nan nan 0 2018 7 nan nan 0 2018 8 78.850 0.348 1 2018 9 79.370 0.331 1 2018 10 79.902 0.566 2 2018 11 79.659 1.001 2 2018 12 79.711 0.325 2 2019 1 79.940 0.353 1 2019 2 79.440 0.453 2 2019 3 79.374 0.245 3 2019 4 79.430 0.398 1 2019 5 79.310 0.450 1 2019 6 79.250 0.426 1 2019 7 79.350 0.587 1 2019 8 79.120 0.219 2 2019 9 nan nan 0 2019 10 nan nan 0 2019 11 nan nan 0 2019 12 nan nan 0