Parts of the U.S. Government are closed. This site will not be updated; however NOAA websites and social media channels necessary to protect lives and property will be maintained. See for critical weather information. To learn more, see
GMD Site Description: GMI


  • Country: Guam Country Flag
  • Latitude: 13.3860° North
  • Longitude: 144.6560° East
  • Elevation: 0.00 masl
  • Time Zone: Local Standard Time + -10.0 hour(s) = UTC


Cooperating Agencies

GMD Projects at Mariana Islands

Carbon Cycle Surface Flasks

Parameter Formula First Sample Date Status
Carbon Dioxide CO2 1978-09-24 Ongoing
Methane CH4 1983-05-02 Ongoing
Carbon Monoxide CO 1989-10-09 Ongoing
Molecular Hydrogen H2 1989-10-09 Ongoing
Nitrous Oxide N2O 1995-12-15 Ongoing
Sulfur Hexafluoride SF6 1995-12-15 Ongoing
Carbon-13/Carbon-12 in Carbon Dioxide d13C (CO2) 1990-01-16 Ongoing
Oxygen-18/Oxygen-16 in Carbon Dioxide d18O (CO2) 1990-01-16 Ongoing
Carbon-13/Carbon-12 in Methane d13C (CH4) 2016-01-20 Ongoing
Methyl Chloride CH3Cl 2005-06-01 Ongoing
Benzene C6H6 2007-01-01 Ongoing
toluene C7H8 2007-01-01 Ongoing
ethane C2H6 2005-06-01 Ongoing
ethene C2H4 2005-06-01 Ongoing
propane C3H8 2005-06-01 Ongoing
propene C3H6 2005-06-01 Ongoing
i-butane i-C4H10 2005-06-01 Ongoing
n-butane n-C4H10 2005-06-01 Ongoing
i-pentane i-C5H12 2005-06-01 Ongoing
n-pentane n-C5H12 2005-06-01 Ongoing
n-hexane n-C6H14 2005-06-01 Ongoing
isoprene C5H8 2007-01-01 Ongoing
Acetylene C2H2 2007-11-19 Ongoing