------------------------------------------------------------------ Readme file to accompany NOAA continuous data: HATS, CH4, CO2 HATS version v20090703, CH4 v20090410, CO2 v20090410 ------------------------------------------------------------------ TERMS AND CONDITIONS (Adapted from NOAA and NACP data policy) ------------------------------------------------------------ Use of these data in any part implies an agreement on the part of the user that individuals and/or institutions responsible for contributing to data sets used must be specifically cited in addition to a general citation of the NACP greenhouse gas database. The NOAA HATS data should be cited as follows: http://www.esrl.noaa.gov/gmd/hats/insitu/cats/cats_conc.html Thompson, T. M. (ed.), J. H. Butler, B. C. Daube, G. S. Dutton, J.W. Elkins, B. D. Hall, D. F. Hurst, D. B. King, E. S. Kline, B. G. Lafleur, J. Lind, S. Lovitz, D.Mondeel, S. A. Montzka, F. L. Moore, J. D. Nance, J. L. New, P. A. Romashkin, A. Scheffer, and W. J. Snible, Halocarbons and Other Atmospheric Trace Species, Chapter 5 in CMDL Summary Report No. 27, 2002-2003, NOAA/US Department of Commerce, Boulder, USA,115-135, 2004. For N2O: Hall, B. D., G. S. Dutton, and J. W. Elkins (2007), The NOAA nitrous oxide standard scale for atmospheric observations, J. Geophys. Res., 112, D09305, doi:10.1029/2006JD007954. For SF6: Peters, W., M.C. Krol, E.J. Dlugokencky, F.J. Dentener, P. Bergamaschi, G. Dutton, P.V. Velthoven, J.B. Miller, L. Bruhwiler, P.P. Tans, Toward regional-scale modeling using the two-way nested global model TM5: Characterization of transport using SF6, J. Geophys. Res., Vol. 109, D19314, doi: 10.1029/2004JD005020, 2004. For CH3Cl: Yoshida, Y; Wang, YH; Shim, C; Cunnold, D; Blake, DR; Dutton, GS, 2006: Inverse modeling of the global methyl chloride sources. J. Geophys. Res.-Atmos.: Vol. 111 For CH4: Dlugokencky, E.J., P.M. Lang, and K.A. Masarie (2009), Atmospheric Methane Dry Air Mole Fractions from quasi-continuous measurements at Barrow, Alaska and Mauna Loa, Hawaii, 1986-2008, Version: 2009-04-10, Path: ftp://ftp.cmdl.noaa.gov/ccg/ch4/in-situ/. For CO2: Thoning, K.W., D.R. Kitzis, and A. Crotwell (2007), Atmospheric Carbon Dioxide Dry Air Mole Fractions from quasi-continuous measurements at Barrow, Alaska; Mauna Loa, Hawaii; American Samoa; and South Pole, 1973-2006, Version: 2009-04-10, Path: ftp://ftp.cmdl.noaa.gov/ccg/co2/in-situ/. NACP investigators will include an acknowledgement in each publication or presentation arising from participation in NACP. The wording shall be similar to the following: "This study was part of the North American Carbon Program." Data providers and funding agencies may request additional acknowledgements. Upon publication of results, investigators should send the NACP Office an electronic copy of the publication. USE OF DATA These data are made freely available to the public and the scientific community in the belief that their wide dissemination will lead to a greater understanding and new scientific insights. The availability of these data does not constitute publication of the data. We rely on the ethics and integrity of the user to assure that the source(s) receive fair credit for their work. If the data are obtained for potential use in a publication or presentation, the source(s) should be informed at the outset of the nature of this work. If the source's data are essential to the work, or if an important result or conclusion depends on their data, co-authorship may be appropriate. This should be discussed at an early stage in the work. Manuscripts using the source's data should be sent to the source(s) for review before they are submitted for publication so we can ensure that the quality and limitations of the data are accurately represented. RECIPROCITY AGREEMENT Use of these data implies an agreement to reciprocate. Laboratories making similar measurements agree to make their own data available to the general public and to the scientific community in an equally complete and easily accessible form. Modelers are encouraged to make available to the community, upon request, their own tools used in the interpretation of the source data, namely well documented model code, transport fields, and additional information necessary for other scientists to repeat the work and to run modified versions. Model availability includes collaborative support for new users of the models. NOAA CONTINUOUS DATA PROJECT PURPOSE & DESCRIPTION -------------------------------------------------- The PIs for the project are: Edward J. Dlugokencky, NOAA/ESRL Global Monitoring Division, ed.dlugokencky@noaa.gov James W. Elkins, NOAA/CMDL HATS group chief, James.W.Elkins@noaa.gov Pieter P. Tans, NOAA/ESRL Global Monitoring Division, pieter.tans@noaa.gov Bradley Hall, NOAA/CMDL HATS group, Bradley.Hall@noaa.gov Geoffrey S. Dutton, NOAA/CMDL HATS group, Geoff.Dutton@noaa.gov I. Introduction The general mission of the Halocarbons and other Atmospheric Trace Species (HATS) group is to quantify the distributions and magnitudes of sources and sinks for atmospheric nitrous oxide (N2O) and halogen containing compounds. HATS utilizes numerous types of platforms, including ground-based stations, towers, ocean vessels, aircraft, and balloons, to accomplish its mission. This data represents in-situ measurements from three of NOAA's ground-based stations, providing data that spans the North American continent and beyond. Stations used by the accompanying data sets: Pt. Barrow, AK, USA (BRW) (71.3230 N; 156.6114 W; 11.00 masl) Niwot Ridge, CO, USA (NWR) (40.0500 N; 105.58 W, 3523.00 masl) Mauna Loa, HI, USA (MLO) (19.5362 N; 155.5763 W; 3397.00 masl) The HATS and N2O data make use of all three of these sites, while CH4 and CO2 measurements represent only BRW and MLO. BRW is located so that it receives minimal influence from anthropogenic effects. It is about 8 km northeast of the village of Barrow and has a prevailing east-northeast wind off the Beaufort Sea. It is attended at least 5 days a week for routine inspection and maintenance of the instrumentation. In addition, the National Weather Service (NWS) maintains a weather observing facility in Barrow. Although the measurements at Barrow are made over open tundra, there are large lagoons and a number of lakes in the vicinity, and the Arctic Ocean is less than 3 km northwest of the site. Because of its proximity to these bodies of water and the fact that the prevailing winds are off the Beaufort Sea, BRW is perhaps best characterized as having an Arctic maritime climate affected by variations of weather and sea ice conditions in the Central Arctic. Established in 1957, Mauna Lao Observatory has grown to become the premier long-term atmospheric monitoring facility on earth and is the site where the ever-increasing concentrations of global atmospheric carbon dioxide were determined. The observatory consists of 10 buildings from which up to 250 different atmospheric parameters are measured by a complement of 12 NOAA/ESRL and other agency scientists and engineers. The in-situ stations employ gas chromatographs (GCs), which provide data beginning in 1998, with continuous operation since 1999. For more information on the NOAA HATS project, visit: http://www.esrl.noaa.gov/gmd/hats/ For data updates from the in-situ Chromatograph for Atmospheric Trace Species (CATS) program, visit: http://www.esrl.noaa.gov/gmd/hats/insitu/cats/cats_conc.html For CH4 data updates, visit: ftp://ftp.cmdl.noaa.gov/ccg/ch4/in-situ/. For CO2 data updates, visit: ftp://ftp.cmdl.noaa.gov/ccg/co2/in-situ/. II. Methods Parameter Method PIs a. CCl4 Gas Chromatograph (GC) J. Elkins, NOAA/CMDL, b. cfc11 for Atmospheric Trace James.W.Elkins@noaa.gov c. cfc113 Species (CATS). These JWE d. cfc12 GCs replaced the JWE e. CH3CCl3 Radiatively Important JWE f. CH3Cl Trace Species (RITS) JWE g. hcfc22 GCs, which were in JWE h. hcfc142b operation from 1986 JWE i. H1211 to 2000 JWE j. N2O JWE k. SF6 JWE l. CH4 Flame Ionization P. Tans, NOAA/ESRL, Detector (FID) pieter.tans@noaa.gov m. CO2 Non-dispersive E. Dlugokencky, NOAA/ESRL infrared analyzer ed.dlugokencky@noaa.gov (NDIR) VARIABLE NAMES -------------- YYYYMMDD : Year, month, and day of sampling doy : Absolute day of year UTC : Coordinated Universal time, in seconds from midnight station : NOAA three-letter code for in-situ measurement site latitude : Latitude of measuring site, in degrees longitude : Longitude of measuring site, in degrees altitude : Altitude of measuring site, in masl CCl4_HATS : Mixing ratio of CCl4 via CATS, in pptv SD.CCl4_HATS : Standard deviation error of CCl4 mixing ratio, in pptv CCl4_HATS.flag : 3-column flags as noted below, for CCl4 measurements cfc11_HATS : Mixing ratio of cfc11 via CATS, in pptv SD.cfc11_HATS : Standard deviation error of cfc11 mixing ratio, in pptv cfc11_HATS.flag : 3-column flags as noted below, for cfc11 measurements cfc113_HATS : Mixing ratio of cfc113 via CATS, in pptv SD.cfc113_HATS : Standard deviation error of cfc113 mixing ratio, in pptv cfc113_HATS.flag: 3-column flags as noted below, for cfc113 measurements cfc12_HATS : Mixing ratio of cfc12 via CATS, in pptv SD.cfc12_HATS : Standard deviation error of cfc12 mixing ratio, in pptv cfc12_HATS.flag : 3-column flags as noted below, for cfc12 measurements CH3Cl_HATS : Mixing ratio of CH3Cl via CATS, in pptv SD.CH3Cl_HATS : Standard deviation error of CH3Cl mixing ratio, in pptv CH3Cl_HATS.flag : 3-column flags as noted below, for CH3Cl measurements CH3CCl3_HATS : Mixing ratio of CH3CCl3 via CATS, in pptv SD.CH3CCl3_HATS : Standard deviation error of CH3CCl3 mixing ratio, in pptv CH3CCl3_HATS.flag: 3-column flags as noted below, for CH3CCl3 measurements CH4_FID : Mixing ratio of CH4 via GC/FID, in ppbv SD.CH4_FID : Standard deviation error of CH4 mixing ratio, in ppbv CH4_FID.flag : 3-column flags as noted below, for CH4 measurements CO2_NDIR : Mixing ratio of CO2 via NDIR, in ppmv SD.CO2_NDIR : Standard deviation error of CO2 mixing ratio, in ppmv CO2_NDIR.flag : 3-column flags as noted below, for CO2 measurements H1211_HATS : Mixing ratio of H1211 via CATS, in pptv SD.H1211_HATS : Standard deviation error of H1211 mixing ratio, in pptv H1211_HATS.flag : 3-column flags as noted below, for H1211 measurements hcfc22_HATS : Mixing ratio of hcfc22 via CATS mixing ratio, in pptv SD.hcfc22_HATS : Standard deviation error of hcfc22 mixing ratio, in pptv hcfc22_HATS.flag: 3-column flags as noted below, for hcfc22 measurements hcfc142b_HATS : Mixing ratio of hcfc142b via CATS, in pptv SD.hcfc142b_HATS: Standard deviation error of hcfc142b mixing ratio, in pptv hcfc142b_HATS.flag: 3-column flags as noted below, for hcfc142b measurements N2O_HATS : Mixing ratio of N2O via CATS, in ppbv SD.N2O_HATS : Standard deviation error of N2O mixing ratio, in ppbv N2O_HATS.flag : 3-column flags as noted below, for N2O SF6_HATS : Mixing ratio of SF6 via CATS, in pptv SD.SF6_HATS : Standard deviation error of SF6 mixing ratio, in pptv SF6_HATS.flag : 3-column flags as noted below, for SF6 measurements ----------------------------------------------------------------------------------- NOAA ESRL uses a 3-column quality control flag where each column is defined as follows: column 1 REJECTION flag. An alphanumeric other than a period (.) in the FIRST column indicates a sample with obvious problems during collection or analysis. This measurement should not be interpreted. column 2 SELECTION flag. An alphanumeric other than a period (.) in the SECOND column indicates a sample that is likely valid but does not meet selection criteria determined by the goals of a particular investigation. column 3 COMMENT flag. An alphanumeric other than a period (.) in the THIRD column provides additional information about the collection or analysis of the sample. WARNING: A "P" in the 3rd column of the QC flag indicates the measurement result is preliminary and has not yet been carefully examined by the PI. The "P" flag is removed once the quality of the measurement has been determined. NOTE: In this data set, REJECTION flag data has been REMOVED. SUMMARY OF SELECTION FLAGS -------------------------- CH4: .C. - data are non-background CO2: .V. - Large variability of CO2 mixing ratio within one hour .D. - Hour-to-hour difference in mixing ratio > 0.25 ppm .A. - Automatic selection based on residuals from a spline curve .U. - Rejected, diurnal variation (upslope) in CO2 (Mauna Loa only) MISSING VALUES ------------- For files in .RData format, missing values are represented by "NA". For files in .csv format, missing values are represented by "NaN".