# file: hfm_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: HFM -- Harvard Forest, Massachusetts -- 42.54 N, 72.17 W, 340 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 "hfm_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 # CCl4ottoHFMyr CCl4ottoHFMmon CCl4ottoHFMm CCl4ottoHFMsd CCl4ottoHFMn 1995 1 nan nan 0 1995 2 nan nan 0 1995 3 nan nan 0 1995 4 nan nan 0 1995 5 nan nan 0 1995 6 nan nan 0 1995 7 nan nan 0 1995 8 nan nan 0 1995 9 105.270 2.485 1 1995 10 nan nan 0 1995 11 105.789 0.325 2 1995 12 nan nan 0 1996 1 nan nan 0 1996 2 105.280 3.444 1 1996 3 nan nan 0 1996 4 105.256 0.445 2 1996 5 nan nan 0 1996 6 104.648 0.549 2 1996 7 nan nan 0 1996 8 105.350 0.400 1 1996 9 105.414 0.975 3 1996 10 104.230 0.719 1 1996 11 105.045 0.545 2 1996 12 nan nan 0 1997 1 104.476 0.371 2 1997 2 nan nan 0 1997 3 104.450 0.433 1 1997 4 nan nan 0 1997 5 105.082 0.735 2 1997 6 104.790 0.372 1 1997 7 104.360 0.396 1 1997 8 104.077 0.650 2 1997 9 103.400 0.623 1 1997 10 104.640 0.969 2 1997 11 nan nan 0 1997 12 103.493 0.551 2 1998 1 103.750 0.523 1 1998 2 103.740 1.075 2 1998 3 nan nan 0 1998 4 nan nan 0 1998 5 104.830 0.973 1 1998 6 103.640 0.174 1 1998 7 105.364 1.944 3 1998 8 105.373 1.542 2 1998 9 103.385 0.357 3 1998 10 103.022 0.551 2 1998 11 102.610 0.340 1 1998 12 103.980 0.418 1 1999 1 103.006 0.255 2 1999 2 102.785 0.339 3 1999 3 nan nan 0 1999 4 nan nan 0 1999 5 102.013 0.196 3 1999 6 102.070 0.206 1 1999 7 101.960 0.249 1 1999 8 nan nan 0 1999 9 101.830 0.248 1 1999 10 nan nan 0 1999 11 102.132 0.304 2 1999 12 101.573 0.320 3 2000 1 101.100 0.213 1 2000 2 101.197 0.613 3 2000 3 101.141 0.191 2 2000 4 100.600 0.553 1 2000 5 101.124 0.348 3 2000 6 100.591 0.375 2 2000 7 100.124 0.504 2 2000 8 100.110 0.355 1 2000 9 100.212 1.718 2 2000 10 100.470 0.270 1 2000 11 101.445 0.544 2 2000 12 100.470 0.260 1 2001 1 100.293 0.714 2 2001 2 99.764 0.637 2 2001 3 99.820 0.312 1 2001 4 99.916 0.238 2 2001 5 99.892 0.502 2 2001 6 99.799 0.585 3 2001 7 99.400 0.201 2 2001 8 98.900 0.625 1 2001 9 99.250 0.418 1 2001 10 99.946 0.279 3 2001 11 99.597 0.891 2 2001 12 nan nan 0 2002 1 99.285 0.259 2 2002 2 98.953 0.785 2 2002 3 99.383 0.375 2 2002 4 99.638 0.577 4 2002 5 98.720 0.231 2 2002 6 98.809 0.346 2 2002 7 98.354 0.226 3 2002 8 98.275 0.237 2 2002 9 98.305 0.175 2 2002 10 98.376 0.262 3 2002 11 99.030 0.298 1 2002 12 98.795 0.877 2 2003 1 97.955 0.403 2 2003 2 97.707 0.198 2 2003 3 98.032 0.178 2 2003 4 97.636 0.168 2 2003 5 97.471 0.297 4 2003 6 97.610 0.217 6 2003 7 96.890 0.257 1 2003 8 97.453 0.353 2 2003 9 96.910 0.250 1 2003 10 96.975 0.648 3 2003 11 97.057 0.311 2 2003 12 96.930 0.212 1 2004 1 96.600 0.236 1 2004 2 96.468 0.304 2 2004 3 96.764 0.636 2 2004 4 96.655 0.170 2 2004 5 96.623 0.225 2 2004 6 96.150 0.228 1 2004 7 96.370 0.189 1 2004 8 96.220 0.180 1 2004 9 96.069 0.530 2 2004 10 96.027 0.217 3 2004 11 96.123 0.332 2 2004 12 nan nan 0 2005 1 95.762 0.096 2 2005 2 95.793 0.159 3 2005 3 95.445 0.247 2 2005 4 95.662 0.265 4 2005 5 95.777 0.337 5 2005 6 95.365 0.312 3 2005 7 95.360 0.334 2 2005 8 95.078 0.345 3 2005 9 95.053 0.246 3 2005 10 95.930 0.247 1 2005 11 97.280 0.542 1 2005 12 nan nan 0 2006 1 94.783 0.495 2 2006 2 nan nan 0 2006 3 94.600 0.276 2 2006 4 94.550 0.224 1 2006 5 94.405 0.381 5 2006 6 94.150 0.230 4 2006 7 93.680 0.345 4 2006 8 93.533 0.183 4 2006 9 93.731 0.334 4 2006 10 93.631 0.217 5 2006 11 93.704 0.182 4 2006 12 94.379 1.489 4 2007 1 93.437 0.166 4 2007 2 93.399 0.962 5 2007 3 92.635 0.417 2 2007 4 92.969 0.328 5 2007 5 93.111 0.163 4 2007 6 93.187 0.160 4 2007 7 92.923 0.279 4 2007 8 93.019 0.226 3 2007 9 92.993 0.172 3 2007 10 92.520 0.415 4 2007 11 92.436 0.203 3 2007 12 92.061 0.170 2 2008 1 92.201 0.222 4 2008 2 92.017 0.275 3 2008 3 91.929 0.361 2 2008 4 91.448 0.233 5 2008 5 91.729 0.203 4 2008 6 91.575 0.276 3 2008 7 91.007 0.207 4 2008 8 90.631 0.237 3 2008 9 90.415 0.220 4 2008 10 90.706 0.211 5 2008 11 90.686 0.203 3 2008 12 90.920 0.232 1 2009 1 90.665 0.332 3 2009 2 89.976 0.172 4 2009 3 90.113 0.172 4 2009 4 89.938 0.231 4 2009 5 89.862 0.216 4 2009 6 89.952 0.179 4 2009 7 89.685 0.182 5 2009 8 89.654 0.164 4 2009 9 89.704 0.233 5 2009 10 89.816 0.188 4 2009 11 89.781 0.226 3 2009 12 89.916 0.206 3 2010 1 89.724 0.167 3 2010 2 89.680 0.152 4 2010 3 89.666 0.308 4 2010 4 89.727 0.394 3 2010 5 89.362 0.174 4 2010 6 89.224 0.334 4 2010 7 89.039 0.657 4 2010 8 88.745 0.169 3 2010 9 89.317 0.565 3 2010 10 88.375 0.160 4 2010 11 88.588 0.247 4 2010 12 88.585 0.168 3 2011 1 88.357 0.241 3 2011 2 88.239 0.178 4 2011 3 88.438 0.391 3 2011 4 88.059 0.286 3 2011 5 87.630 0.143 3 2011 6 87.597 0.121 4 2011 7 87.561 0.311 3 2011 8 87.162 0.163 4 2011 9 87.346 0.141 5 2011 10 87.546 0.342 4 2011 11 87.547 0.188 5 2011 12 87.782 0.587 2 2012 1 87.201 0.283 2 2012 2 86.959 0.301 3 2012 3 87.156 0.242 2 2012 4 86.507 0.351 5 2012 5 86.665 0.347 4 2012 6 86.982 0.318 2 2012 7 86.475 0.269 4 2012 8 86.004 0.222 3 2012 9 86.085 0.199 3 2012 10 86.183 0.544 3 2012 11 85.760 0.250 2 2012 12 86.120 0.279 2 2013 1 85.970 0.410 2 2013 2 85.803 0.651 4 2013 3 nan nan 0 2013 4 85.742 0.270 3 2013 5 nan nan 0 2013 6 85.660 0.278 1 2013 7 85.640 0.425 4 2013 8 85.000 0.353 1 2013 9 nan nan 0 2013 10 nan nan 0 2013 11 85.310 0.260 1 2013 12 84.945 0.339 3 2014 1 84.550 0.272 1 2014 2 84.709 0.173 2 2014 3 84.994 0.495 4 2014 4 84.761 0.262 2 2014 5 nan nan 0 2014 6 85.010 0.256 1 2014 7 84.516 0.381 4 2014 8 84.376 0.211 4 2014 9 84.268 0.272 4 2014 10 84.221 0.189 4 2014 11 84.483 0.597 3 2014 12 84.119 0.278 3 2015 1 83.750 0.217 1 2015 2 83.140 0.702 1 2015 3 nan nan 0 2015 4 82.950 0.302 1 2015 5 83.309 0.241 2 2015 6 83.167 0.321 4 2015 7 83.276 0.261 3 2015 8 83.028 0.317 4 2015 9 82.997 0.232 4 2015 10 82.802 0.325 2 2015 11 83.051 0.328 4 2015 12 82.913 0.395 3 2016 1 nan nan 0 2016 2 82.280 0.515 1 2016 3 82.422 0.463 3 2016 4 82.438 0.658 2 2016 5 82.327 0.309 3 2016 6 82.523 0.328 2 2016 7 82.490 0.405 1 2016 8 82.286 0.430 4 2016 9 82.496 0.474 2 2016 10 nan nan 0 2016 11 81.915 0.246 2 2016 12 82.118 0.707 2 2017 1 81.754 0.174 2 2017 2 81.371 0.204 3 2017 3 81.642 0.274 2 2017 4 81.240 0.386 1 2017 5 81.545 0.512 4 2017 6 81.013 0.329 3 2017 7 81.615 0.226 3 2017 8 81.033 0.976 3 2017 9 80.749 0.370 4 2017 10 81.375 1.046 2 2017 11 80.534 0.395 3 2017 12 81.392 0.724 3 2018 1 80.865 0.728 3 2018 2 80.385 1.112 3 2018 3 80.091 0.433 2 2018 4 80.390 0.240 1 2018 5 80.970 0.242 1 2018 6 79.888 0.778 2 2018 7 nan nan 0 2018 8 78.900 0.185 1 2018 9 79.590 0.267 1 2018 10 79.493 0.403 2 2018 11 80.332 0.881 3 2018 12 79.579 0.629 3 2019 1 79.490 0.266 3 2019 2 nan nan 0 2019 3 80.860 0.557 1 2019 4 79.800 0.383 4 2019 5 79.453 0.423 4 2019 6 79.102 0.273 3 2019 7 79.131 0.273 3 2019 8 78.870 0.498 1 2019 9 nan nan 0 2019 10 nan nan 0 2019 11 nan nan 0 2019 12 nan nan 0