The NOAA Halocarbons and other Trace Gases ()

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Figure 5: HATS Stations. Circles=flask sites, boxes=in situ sites, planes=airborne sites. For more details: see http://www.esrl.noaa.gov/gmd/hats/network.php. Credit ESRL GMD.

The National Oceanic and Atmospheric Administration’s Earth System Research Laboratory (NOAA/ESRL) maintains a global in situ and flask network for the measurement and analysis of halocarbons and other atmospheric trace gases. The network started in 1977 with three trace gases (nitrous oxide, CFC-11, CFC-12) at five flask locations, and has grown to include over 40 trace gases at over 30 locations and airborne campaigns that include both flask and in situ monitoring. The purpose of this work is to study atmospheric trace gases that affect climate change, stratospheric ozone depletion, and air quality from observations at NOAA and cooperating stations. Some atmospheric trace gases (e.g., SF6) are used as atmospheric clocks to provide important information on atmospheric transport. Areas of common interest with NDACC include the (1) species measured by Fourier Transform Infrared Spectrometers (halocarbons, O3, HCl, HF, CO, N2O, CH4), water vapor, ozone, and Lidar instruments; and (2) collocated stations at Barrow, Boulder, Mauna Loa, Summit, American Samoa, Palmer, and South Pole.

The analyses of flask samples and in situ data are conducted within the Global Monitoring Division (GMD) in Boulder, Colorado, USA. Through collaborations with the National Aeronautics and Space Administration (NASA) and the National Science Foundation (NSF), III-10 NOAA/ESRL operates a number of in situ and flask collection instruments from NASA and NSF high-altitude, manned, and unmanned (UAS) aircraft up to 21 km, and balloon platforms up to 32 km. These measurements have been associated with high-altitude campaigns that have spanned the globe since 1991. HATS began vertical profiling of many trace gases from flask samples collected on NOAA-operated, small aircraft (<=25000 ft asl) in 2004. These measurements now include 25 sites.

The HATS Network measures over 40 trace gases in the atmosphere, including nitrous oxide (N2O); chlorofluorocarbons (CFCs, CFC-11, -12, -113, -115); hydrochlorofluorocarbons (HCFCs, HCFC-22, -141b, -142b); hydrofluorocarbons (HFCs, HFC-134a, 143a,152a, 125, 32, 227ea, 365mfc); methyl halides (CH3Cl, CH3Br, CH3I); chlorinated (CHCl3, CH3CCl3, CCl4, C2Cl4, CH2Cl2); and brominated (CHBr3, CH2Br2) solvents; sulfur gases (COS, SF6); and selected hydrocarbons (C2H2, C3H8, nC4H10, C5H12, nC5H12, C6H6, nC6H14). Water vapor (H2O) and ozone (O3) also have been measured on NASA airborne campaigns since 2005. In situ atmospheric H2, CO, and CH4 are measured at Summit, Greenland, and during most high-altitude airborne campaigns.

NOAA HATS provides data to calculate atmospheric indices, including the Annual Greenhouse Gas Index (AGGI), Ozone Depleting Gases Index (ODGI), equivalent effective chlorine, total bromine, and total fluorine in the atmosphere. This research has resulted in numerous peerreviewed publications, and has contributed to international assessments of climate and ozone depletion. Data are available via anonymous ftp, and discussions are available at the HATS website.

Dr. James W. Elkins, Group Chief, is responsible for the Network and airborne measurements within the HATS group. Dr. Stephen A. Montzka is the Principal Investigator responsible for the gas chromatograph and mass selection detection of flask samples collected from stations located globally, and also from regional aircraft that sample the troposphere. Dr. Bradley D. Hall is the Principal Investigator in charge of trace-gas standards research, and the preparation of most of the Group’s trace gas standards. Geoffrey S. Dutton is the Principal Investigator responsible for in situ measurements at stations located at Pt. Barrow, Alaska; Summit, Greenland; Niwot Ridge, Colorado; Mauna Loa, Hawaii; Cape Matatula, American Samoa; and South Pole, Antarctica. Drs. Fred L. Moore and Eric J. Hintsa are Co-P.I.s responsible for high-altitude airborne measurements on NASA aircraft.

Of the many sites noted on the HATS web page, the following are relevant to NDACC interests.