# file: itn_N2O_All.dat # # Atmospheric measurements of N2O (Nitrous Oxide) # # Measurements are from the NOAA/ESRL/GMD/HATS flask program # (http://www.esrl.noaa.gov/gmd/hats/flask/flasks.html). # Instrument ID: Otto # # Location: ITN -- Grifton, North Carolina -- 35.37 N, 77.39 W, 8 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. # # A known, systematic, low-side bias in the N2O measurements performed on Otto # has largely been eliminated since January of 2009. Prior to this date, # offsets are added to these flask data for the purpose of combining them with # baseline N2O data from other monitoring systems (see # http://www.esrl.noaa.gov/gmd/hats/ combined/N2O.html). The offsets -- 1.3 ppb # at Samoa and 0.6 ppb elsewhere -- were determined in reference to CATS data # (http://www.esrl.noaa.gov/gmd/hats/ insitu/cats) but have not been applied to # the Otto data reported here. # # 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 # "itn_N2O_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: Nitrous Oxide # data from the NOAA/ESRL halocarbons flask program. # # Calibration scale: NOAA 2006A # See http://www.esrl.noaa.gov/gmd/ccl/scales.html for more information about # calibration scales. # # Units: ppb # # 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 N2O in ppb # 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 ("itn_N2O_MM.dat") # N2OottoITNyr N2OottoITNmon N2OottoITNday N2OottoITNhour N2OottoITNmin N2OottoITNm N2OottoITNsd N2OottoITNpid N2OottoITNftype N2OottoITNflag1 N2OottoITNflag2 N2OottoITNflag3 N2OottoITNflag4 N2OottoITNflag5 N2OottoITNflag6 N2OottoITNflag7 1995 08 16 16 19 311.156 1.662 00239 S 0 0 0 0 0 0 0 1995 09 20 15 59 311.955 1.077 00269 S 0 0 0 0 0 0 0 1995 10 25 15 00 311.414 0.950 00295 S 0 0 0 0 0 0 0 1995 11 22 16 12 311.538 1.560 00344 S 0 0 0 0 0 0 0 1996 01 03 18 17 313.237 1.456 00372 S 0 0 0 0 0 0 0 1996 01 17 17 50 310.880 3.404 00384 S 0 0 0 0 0 0 0 1996 02 21 16 19 311.547 1.112 00413 S 0 0 0 0 0 0 0 1996 03 27 15 25 312.409 0.757 00451 S 0 0 0 0 1 0 1 1996 04 10 14 35 312.102 1.672 00462 S 0 0 0 0 0 0 0 1996 05 01 15 14 312.501 0.869 00478 S 0 0 0 0 0 0 0 1996 05 15 16 44 311.127 0.979 00494 S 0 0 0 0 0 0 0 1996 05 29 16 55 312.327 3.191 00502 S 0 0 0 0 0 0 0 1996 06 12 17 15 312.837 1.106 00521 S 0 0 0 0 0 0 0 1996 06 26 16 25 312.512 0.629 00537 S 0 0 0 0 0 0 0 1996 07 10 16 25 313.433 0.460 00552 S 0 0 0 0 0 0 0 1996 07 24 15 55 313.295 0.592 00563 S 0 0 0 0 0 0 0 1996 08 07 16 25 313.342 0.803 00567 S 0 0 0 0 0 0 0 1996 08 21 15 30 312.930 0.828 00592 S 0 0 0 0 0 0 0 1996 09 04 15 30 312.210 0.931 00606 S 0 0 0 0 0 0 0 1996 09 18 15 50 312.742 0.667 00618 S 0 0 0 0 0 0 0 1996 10 23 16 25 313.141 1.055 00648 S 0 0 0 0 0 0 0 1996 11 06 17 14 312.004 0.716 00658 S 0 0 0 0 0 0 0 1996 11 27 16 54 312.435 1.198 00689 S 0 0 0 0 0 0 0 1996 12 11 16 44 313.718 0.817 00698 S 0 0 0 0 0 0 0 1997 01 02 16 55 312.810 0.780 00728 S 0 0 0 0 0 0 0 1997 01 22 16 44 312.555 0.907 00738 S 0 0 0 0 0 0 0 1997 02 05 16 25 312.881 0.364 00759 S 0 0 0 0 0 0 0 1997 02 19 16 15 313.391 0.728 00770 S 0 0 0 0 0 0 0 1997 03 26 17 15 313.062 1.209 00802 S 0 0 0 0 0 0 0 1997 04 09 16 50 313.398 0.748 00815 S 0 0 0 0 0 0 0 1997 04 23 15 24 307.252 18.728 00822 S 0 0 1 1 0 0 1 1997 07 02 16 20 312.717 0.786 00884 S 0 0 0 0 0 0 0 1997 07 16 16 25 313.483 0.273 00897 S 0 0 0 0 0 0 0 1997 08 13 16 04 312.559 0.594 00935 S 0 0 0 0 0 0 0 1997 08 27 16 09 313.238 0.714 00940 S 0 0 0 0 0 0 0 1997 09 17 16 44 313.283 0.642 00954 S 0 0 0 0 0 0 0 1997 10 08 15 49 314.025 0.344 00971 S 0 0 0 0 0 0 0 1997 10 29 16 34 314.009 1.073 00984 S 0 0 0 0 0 0 0 1997 11 19 16 40 312.981 0.627 01005 S 0 0 0 0 0 0 0 1997 12 10 16 55 312.846 0.464 01047 S 0 0 0 0 0 0 0 1998 01 07 17 00 313.493 0.457 01061 S 0 0 0 0 0 0 0 1998 01 28 16 49 312.805 0.805 01079 S 0 0 0 0 0 0 0 1998 02 18 16 44 313.884 0.592 01103 S 0 0 0 0 0 0 0 1998 03 11 17 15 314.233 0.704 01118 S 0 0 0 0 0 0 0 1998 04 01 16 55 313.103 0.651 01136 S 0 0 0 0 0 0 0 1998 04 15 14 49 314.096 0.311 01153 S 0 0 0 0 0 0 0 1998 05 27 15 44 315.434 0.745 01191 S 0 0 0 0 0 0 0 1998 06 24 15 19 315.384 1.032 01221 S 0 0 0 0 0 0 0 1998 07 01 15 45 315.221 0.340 01224 S 0 0 0 0 0 0 0 1998 08 19 15 44 315.297 0.469 01284 S 0 0 0 0 0 0 0 1998 09 15 16 14 313.767 0.822 01308 S 0 0 0 0 0 0 0 1998 10 07 16 05 314.492 0.527 01334 S 0 0 0 0 0 0 0 1998 10 28 16 40 314.599 0.540 01358 S 0 0 0 0 0 0 0 1998 11 25 15 14 313.894 0.627 01397 S 0 0 0 0 0 0 0 1998 12 09 17 15 314.799 0.700 01428 S 0 0 0 0 0 0 0 1998 12 30 16 55 314.397 0.303 01436 S 0 0 0 0 0 0 0 1999 01 27 15 20 315.235 0.299 01459 S 0 0 0 0 0 0 0 1999 02 10 16 34 314.543 0.378 01483 S 0 0 0 0 0 0 0 1999 03 03 16 24 314.377 0.774 01522 S 0 0 0 0 0 0 0 1999 03 24 15 59 315.327 4.550 01529 S 0 0 0 0 0 0 0 1999 04 21 15 25 314.798 0.782 01553 S 0 0 0 0 0 0 0 1999 05 05 15 05 313.617 0.421 01575 S 0 0 0 1 0 0 1 1999 05 12 15 34 313.922 0.622 01587 S 0 0 0 0 0 0 0 1999 05 26 14 34 313.975 0.476 01599 S 0 0 0 0 0 0 0 1999 06 02 15 19 314.574 0.480 01608 S 0 0 0 0 0 0 0 1999 06 09 14 39 315.471 0.433 01618 S 0 0 0 0 0 0 0