# file: alt_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: ALT -- Alert, Canada -- 82.45 N, 62.51 W, 200 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 "alt_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 # CCl4ottoALTyr CCl4ottoALTmon CCl4ottoALTm CCl4ottoALTsd CCl4ottoALTn 1996 1 nan nan 0 1996 2 nan nan 0 1996 3 nan nan 0 1996 4 nan nan 0 1996 5 105.103 0.715 2 1996 6 105.172 0.410 2 1996 7 105.360 0.417 1 1996 8 104.184 0.324 2 1996 9 104.380 0.351 1 1996 10 nan nan 0 1996 11 105.100 0.877 1 1996 12 nan nan 0 1997 1 nan nan 0 1997 2 nan nan 0 1997 3 103.680 0.314 1 1997 4 nan nan 0 1997 5 104.030 0.413 1 1997 6 104.100 0.489 3 1997 7 104.180 0.710 1 1997 8 nan nan 0 1997 9 nan nan 0 1997 10 103.770 0.358 1 1997 11 nan nan 0 1997 12 nan nan 0 1998 1 nan nan 0 1998 2 nan nan 0 1998 3 nan nan 0 1998 4 102.380 1.252 1 1998 5 102.880 0.415 1 1998 6 103.170 0.314 1 1998 7 nan nan 0 1998 8 102.265 0.672 2 1998 9 102.702 0.440 4 1998 10 nan nan 0 1998 11 101.830 1.016 1 1998 12 nan nan 0 1999 1 nan nan 0 1999 2 nan nan 0 1999 3 101.750 0.273 1 1999 4 nan nan 0 1999 5 101.806 0.345 4 1999 6 101.475 0.361 2 1999 7 101.094 0.189 3 1999 8 101.057 0.290 3 1999 9 101.320 0.258 1 1999 10 101.181 0.239 2 1999 11 nan nan 0 1999 12 nan nan 0 2000 1 nan nan 0 2000 2 nan nan 0 2000 3 99.560 0.537 1 2000 4 100.230 1.000 1 2000 5 nan nan 0 2000 6 100.730 0.355 1 2000 7 100.797 0.325 4 2000 8 99.992 0.391 3 2000 9 nan nan 0 2000 10 nan nan 0 2000 11 99.803 0.290 2 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 99.882 0.302 5 2001 6 99.861 0.244 2 2001 7 99.540 0.212 4 2001 8 99.522 0.306 3 2001 9 99.190 0.290 2 2001 10 98.862 0.792 2 2001 11 nan nan 0 2001 12 99.289 0.281 3 2002 1 99.080 0.386 1 2002 2 nan nan 0 2002 3 98.960 0.235 1 2002 4 98.514 0.230 2 2002 5 98.497 0.209 3 2002 6 98.247 0.268 3 2002 7 98.250 0.286 5 2002 8 97.998 0.219 4 2002 9 98.119 0.179 4 2002 10 97.240 0.259 1 2002 11 96.740 0.608 1 2002 12 98.050 0.195 1 2003 1 97.280 0.663 1 2003 2 98.200 0.291 1 2003 3 nan nan 0 2003 4 97.514 0.202 2 2003 5 97.320 0.138 3 2003 6 97.237 0.219 4 2003 7 97.251 0.140 5 2003 8 96.844 0.125 4 2003 9 96.712 0.286 4 2003 10 96.331 0.172 4 2003 11 nan nan 0 2003 12 nan nan 0 2004 1 nan nan 0 2004 2 nan nan 0 2004 3 96.171 0.255 2 2004 4 nan nan 0 2004 5 96.365 0.257 3 2004 6 96.513 0.243 5 2004 7 96.322 0.161 3 2004 8 95.978 0.291 3 2004 9 95.311 0.296 4 2004 10 94.986 0.214 2 2004 11 94.975 0.247 2 2004 12 95.600 0.174 1 2005 1 95.489 0.371 3 2005 2 95.635 0.318 2 2005 3 95.276 0.288 3 2005 4 95.456 0.376 3 2005 5 95.945 0.820 2 2005 6 95.371 0.222 5 2005 7 95.347 0.180 4 2005 8 94.931 0.215 5 2005 9 94.809 0.250 3 2005 10 94.874 0.771 2 2005 11 94.270 0.389 1 2005 12 nan nan 0 2006 1 93.765 0.439 3 2006 2 93.840 0.369 1 2006 3 93.760 0.180 1 2006 4 94.163 0.176 2 2006 5 94.324 0.286 4 2006 6 94.011 0.216 4 2006 7 93.886 0.182 4 2006 8 93.560 0.308 4 2006 9 93.422 0.214 4 2006 10 93.642 0.155 4 2006 11 93.470 0.565 1 2006 12 93.062 0.239 3 2007 1 92.960 0.222 1 2007 2 92.864 0.380 2 2007 3 92.860 0.214 1 2007 4 93.120 0.239 1 2007 5 92.848 0.266 4 2007 6 93.058 0.293 4 2007 7 93.203 0.264 4 2007 8 92.592 0.510 5 2007 9 92.273 0.335 4 2007 10 91.984 0.262 4 2007 11 92.070 0.467 2 2007 12 91.980 0.266 1 2008 1 nan nan 0 2008 2 nan nan 0 2008 3 91.546 0.218 2 2008 4 nan nan 0 2008 5 91.282 0.288 3 2008 6 91.095 0.200 4 2008 7 90.884 0.197 5 2008 8 90.842 0.207 4 2008 9 90.695 0.376 3 2008 10 90.906 0.558 3 2008 11 90.639 0.622 2 2008 12 90.295 0.668 3 2009 1 90.390 0.248 1 2009 2 90.093 0.223 2 2009 3 89.589 0.244 2 2009 4 89.657 0.424 2 2009 5 89.853 0.279 4 2009 6 89.629 0.164 5 2009 7 89.911 0.185 4 2009 8 89.792 0.193 4 2009 9 89.532 0.247 4 2009 10 89.602 0.233 2 2009 11 89.620 0.281 1 2009 12 89.863 0.174 3 2010 1 88.570 0.454 1 2010 2 88.960 0.366 1 2010 3 89.079 0.265 3 2010 4 89.514 0.265 3 2010 5 89.294 0.206 4 2010 6 89.232 0.123 5 2010 7 88.953 0.236 4 2010 8 88.979 0.264 4 2010 9 88.497 0.244 4 2010 10 88.138 0.309 3 2010 11 88.620 0.151 2 2010 12 88.663 0.290 2 2011 1 88.480 0.256 2 2011 2 88.304 0.291 3 2011 3 88.320 1.253 3 2011 4 87.336 0.183 2 2011 5 87.852 0.369 3 2011 6 87.854 0.199 4 2011 7 nan nan 0 2011 8 87.570 0.189 1 2011 9 87.140 0.211 5 2011 10 87.149 0.262 4 2011 11 87.258 0.366 3 2011 12 87.323 0.240 3 2012 1 86.990 0.139 1 2012 2 87.260 0.163 1 2012 3 86.667 0.474 2 2012 4 86.680 0.133 1 2012 5 87.036 0.287 4 2012 6 86.958 0.163 4 2012 7 86.186 0.264 4 2012 8 86.153 0.365 5 2012 9 86.179 0.189 4 2012 10 85.785 0.385 3 2012 11 85.657 0.496 5 2012 12 85.420 0.322 1 2013 1 85.472 0.222 2 2013 2 nan nan 0 2013 3 85.848 0.498 3 2013 4 85.639 0.679 2 2013 5 85.683 0.257 4 2013 6 85.641 0.361 4 2013 7 85.577 0.427 3 2013 8 84.730 0.202 1 2013 9 84.390 1.873 1 2013 10 85.179 0.226 2 2013 11 84.850 0.216 1 2013 12 84.567 0.344 2 2014 1 nan nan 0 2014 2 83.840 0.393 1 2014 3 83.960 0.333 1 2014 4 nan nan 0 2014 5 nan nan 0 2014 6 84.520 0.266 3 2014 7 84.325 0.161 5 2014 8 84.359 0.402 4 2014 9 84.355 0.293 3 2014 10 84.081 0.422 3 2014 11 84.270 0.333 1 2014 12 84.090 0.202 1 2015 1 83.692 0.516 2 2015 2 nan nan 0 2015 3 nan nan 0 2015 4 82.780 0.842 1 2015 5 83.338 0.306 2 2015 6 83.474 0.213 4 2015 7 83.095 0.246 4 2015 8 82.841 0.181 4 2015 9 82.839 0.211 3 2015 10 82.939 0.691 3 2015 11 82.326 0.275 3 2015 12 nan nan 0 2016 1 81.910 0.347 1 2016 2 82.032 0.594 2 2016 3 82.270 0.429 1 2016 4 81.838 0.388 2 2016 5 82.284 0.282 5 2016 6 82.512 0.376 4 2016 7 82.280 1.032 1 2016 8 82.102 0.535 3 2016 9 81.506 0.336 4 2016 10 81.816 0.291 2 2016 11 nan nan 0 2016 12 80.988 0.573 2 2017 1 81.367 0.400 2 2017 2 81.580 0.337 1 2017 3 82.153 0.291 2 2017 4 81.269 0.523 2 2017 5 80.883 0.413 4 2017 6 80.885 0.237 3 2017 7 81.242 0.258 4 2017 8 81.395 0.231 2 2017 9 80.787 0.617 4 2017 10 80.772 0.780 3 2017 11 80.276 0.251 2 2017 12 80.260 0.302 1 2018 1 80.970 0.292 1 2018 2 79.835 0.241 3 2018 3 nan nan 0 2018 4 79.250 0.289 1 2018 5 79.892 0.318 3 2018 6 79.600 0.656 1 2018 7 nan nan 0 2018 8 79.446 0.531 4 2018 9 79.047 0.640 4 2018 10 79.530 0.543 4 2018 11 79.526 0.870 2 2018 12 79.730 0.639 1 2019 1 79.033 0.569 2 2019 2 78.780 0.594 2 2019 3 78.987 0.226 2 2019 4 78.740 0.707 2 2019 5 79.654 0.304 3 2019 6 79.379 0.660 3 2019 7 78.530 0.360 1 2019 8 nan nan 0 2019 9 nan nan 0 2019 10 nan nan 0 2019 11 nan nan 0 2019 12 nan nan 0