# file: ush_CCl4_All.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: USH -- Ushuaia, Argentina -- 54.82 S, 68.33 W, 20 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 mean estimates from pairs of concurrently-collected # flask samples based on several injections from each flask. Mean estimates # are derived for each individual flask, then the flask estimates are combined # into a single estimate for the pair. Ideally, each concentration is estimated # three different ways using three simple calibration curves. A two-point # calibration is derived from nearby responses to both reference gases # considered in unison, and separate one-point calibrations are derived from # nearby responses to each reference gas considered in isolation from the # other. These estimates are then reconciled in accordance with the method # outlined at # # ftp://aftp.cmdl.noaa.gov/data/hats/doc/HATSflaskECDanalysis.docx # # A series of seven binary QC flag fields is included with each entry. In order # from left to right, a 1 signifies that 1) a single reference gas was used for # calibration, 2) one or more sample injections occurred at subambient flask # pressure (raising the risk of contamination), 3) the precision of the # estimate is worse than 2.5% of the mean, 4) the estimate has been flagged -- # either by a loess-based statistical outlier algorithm, or, on occasion, # selectively -- as "suspect", 5) the estimate is based on a single flask # sample with a missing paired partner, 6) the estimates from the individual # flask partners disagree by more than twice their summed precisions. The # seventh and final flag is turned on whenever one of flags 4, 5 or 6 is # thrown. This is to conveniently mark samples that are excluded from the # computation of monthly mean values presented in the companion file named # "ush_CCl4_MM.dat". Flags 1, 2 and 3 are considered purely descriptive in # nature, serving only to raise suspicion of a sample. Flag 4 promotes any # suspicion to exclusionary status. The algorithm used for setting flag 4 is # applied only to baseline (i.e. coastal, high-altitude, or otherwise remote) # sites. Samples from continental sites known to have nearby urban influences # (e.g. HFM, ITN, and LEF) are flagged as suspect only when obvious # chromatography issues were present during the analysis. This elevates the # risk of sample over-exclusion (i.e. false positives occurring in flag 4 and # hence also in flag 7) among the baseline sites, while for the continental, # urban-influenced sites there is a greater risk of sample under-exclusion. # # 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 # day Day of the Month # hour Hour of the Day # min Minute of the Hour # m Mean flask-pair concentration of CCl4 in ppt # sd Standard deviation # pid Flask-pair ID # ftype Type of flasks in pair # U: unknown # S: stainless steel # G: glass # B: both (i.e. one of each) # flag1 0: normal (this also applies to all flags that follow) # 1: a single reference gas was used for calibration # flag2 1: one or more sample injections occurred at subambient pressure # flag3 1: precision > 2.5% of estimated concentration # flag4 1: marked suspect by a loess-based statistical outlier algorithm # flag5 1: single flask with missing paired partner # flag6 1: paired partners disagree by more than twice their summed # precisions # flag7 1: sample excluded from monthly mean computations ("ush_CCl4_MM.dat") # CCl4ottoUSHyr CCl4ottoUSHmon CCl4ottoUSHday CCl4ottoUSHhour CCl4ottoUSHmin CCl4ottoUSHm CCl4ottoUSHsd CCl4ottoUSHpid CCl4ottoUSHftype CCl4ottoUSHflag1 CCl4ottoUSHflag2 CCl4ottoUSHflag3 CCl4ottoUSHflag4 CCl4ottoUSHflag5 CCl4ottoUSHflag6 CCl4ottoUSHflag7 2004 05 28 16 00 94.484 0.247 04130 S 0 0 0 0 0 0 0 2004 06 11 16 30 94.478 0.175 04131 S 0 0 0 0 0 0 0 2004 07 06 15 05 93.992 0.184 04319 S 0 0 0 1 0 0 1 2004 07 26 14 54 94.453 0.276 04322 S 0 0 0 0 0 0 0 2004 08 11 13 35 94.031 0.386 04320 S 0 0 0 1 0 0 1 2005 04 05 13 35 93.566 0.278 04772 S 0 0 0 0 0 0 0 2005 05 18 14 50 94.237 0.270 04901 S 0 0 0 0 0 0 0 2005 06 15 14 19 93.367 0.192 04889 S 0 0 0 0 0 0 0 2005 07 10 15 14 93.600 0.227 04918 S 0 0 0 0 0 0 0 2005 08 28 14 30 92.964 0.319 04917 S 0 0 0 1 0 0 1 2005 09 19 14 19 93.281 0.228 04933 S 0 0 0 0 0 0 0 2006 01 04 13 54 93.432 0.215 05236 S 0 0 0 0 0 0 0 2006 01 25 14 14 92.087 0.218 05221 S 0 1 0 1 0 0 1 2006 02 23 13 54 93.071 0.352 05220 S 0 0 0 0 0 0 0 2006 03 15 14 24 92.957 0.183 05345 S 0 0 0 0 0 0 0 2006 03 31 13 04 93.051 0.172 05346 S 0 0 0 0 0 0 0 2006 06 07 13 14 92.388 0.208 05482 S 0 0 0 0 0 0 0 2006 07 27 10 18 92.481 0.224 05483 S 0 0 0 0 0 0 0 2006 08 16 13 04 92.145 0.154 05484 S 0 0 0 0 0 0 0 2006 09 26 14 10 92.048 0.130 05670 S 0 0 0 0 0 0 0 2006 10 24 14 00 92.092 0.237 05671 S 0 0 0 0 0 0 0 2006 12 28 13 44 92.023 0.341 05797 S 0 0 0 0 0 0 0 2007 02 19 14 10 91.785 0.311 05796 S 0 0 0 0 0 0 0 2007 04 02 14 15 91.161 0.251 05943 S 0 0 0 0 0 0 0 2007 05 12 14 14 91.818 0.362 06062 S 0 0 0 0 0 0 0 2007 06 06 13 54 91.400 0.160 06063 S 0 0 0 0 1 0 1 2007 06 27 14 30 91.685 0.331 06064 S 0 0 0 0 0 0 0 2007 08 07 13 54 90.892 0.286 06113 S 0 0 0 0 0 0 0 2007 08 31 13 49 90.430 0.196 06114 S 0 0 0 0 0 0 0 2007 11 02 13 29 90.753 0.227 06230 S 0 0 0 0 1 0 1 2007 11 26 12 57 90.671 0.223 06361 S 0 0 0 0 0 0 0 2008 01 14 13 40 90.661 0.217 06362 S 0 0 0 0 0 0 0 2008 03 04 13 10 90.573 0.311 06530 S 0 0 0 0 0 0 0 2008 03 18 12 30 90.328 0.382 06531 S 0 0 0 0 0 0 0 2008 04 22 12 44 90.022 0.285 06532 S 0 0 0 0 0 0 0 2008 06 11 12 45 89.421 0.283 06634 S 0 0 0 0 0 0 0 2008 08 22 13 50 89.215 0.287 06912 S 0 0 0 0 0 0 0 2008 09 12 12 55 89.248 0.256 06913 S 0 0 0 0 0 0 0 2008 10 09 13 49 89.198 0.441 06914 S 0 0 0 0 0 0 0 2008 12 26 13 25 89.261 0.391 06995 S 0 0 0 0 0 0 0 2009 01 09 13 34 89.047 0.178 06994 S 0 0 0 0 0 0 0 2009 04 06 13 00 88.604 0.249 07119 S 0 0 0 0 0 0 0 2009 04 27 13 24 88.966 0.145 07311 S 0 0 0 0 0 0 0 2009 05 30 15 35 88.901 0.191 07312 S 0 0 0 0 0 0 0 2009 07 15 13 30 88.463 0.194 07313 S 0 0 0 0 0 0 0 2009 08 07 14 40 88.400 0.229 07314 S 0 0 0 0 0 0 0 2009 09 25 14 39 88.568 0.194 07393 S 0 0 0 0 0 0 0 2009 11 06 17 11 88.350 0.205 07535 S 0 0 0 0 0 0 0 2009 11 23 20 53 88.495 0.125 07536 S 0 0 0 0 0 0 0 2009 12 11 13 59 88.371 0.213 07568 S 0 0 0 0 0 0 0 2010 01 15 15 54 88.340 0.204 07663 S 0 0 0 0 0 0 0 2010 01 29 16 05 88.533 0.207 07664 S 0 0 0 0 0 0 0 2010 04 18 16 19 87.847 0.312 07828 S 1 0 0 0 0 0 0 2010 05 14 16 45 87.778 0.312 07829 S 1 0 0 0 0 0 0 2010 05 28 16 34 87.248 0.219 07824 S 1 0 0 0 0 0 0