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GMD Site Description: SMO


  • Country: American Samoa Country Flag
  • Latitude: 14.2474° South
  • Longitude: 170.5644° West
  • Elevation: 42.00 masl
  • Time Zone: Local Time + 11.0 hour(s) = UTC


  • Contact Name: Diane Perry
  • Address: NOAA Samoa Observatory
    P.O. Box 2568
    Pago Pago, Cape Matatula, 96799, American Samoa
  • Phone: 684-258-2848
  • Fax:


The Samoa Observatory is located on the northeastern tip of Tutuila island, American Samoa, on a ridge overlooking the South Pacific Ocean. Established in 1974 on a 26.7 acre site, the observatory is one of six GMD Baseline Observatories. Cape Matatula is approx. 1 km from the village of Tula. Prevailing winds are marine. Since it's construction, the Samoa Observatory has survived two major hurricanes with only minor damage. A staff of 2 operates the year around facility commuting to work. This Observatory has the distinction of obtaining 30% of its daytime power from solar panels.

GMD Projects at Tutuila

Carbon Cycle Surface Flasks

Parameter Formula First Sample Date Status
Carbon Dioxide CO2 1972-01-15 Ongoing
Methane CH4 1983-04-23 Ongoing
Carbon Monoxide CO 1988-09-22 Ongoing
Molecular Hydrogen H2 1989-01-05 Ongoing
Nitrous Oxide N2O 1997-05-07 Ongoing
Sulfur Hexafluoride SF6 1997-05-07 Ongoing
Carbon-13/Carbon-12 in Carbon Dioxide d13C (CO2) 1990-01-04 Ongoing
Oxygen-18/Oxygen-16 in Carbon Dioxide d18O (CO2) 1990-01-04 Ongoing
Carbon-13/Carbon-12 in Methane d13C (CH4) 1998-01-06 Ongoing
D/H in Methane dD (CH4) 2005-03-28 Terminated - 2009-09-11
Methyl Chloride CH3Cl 2005-05-12 Ongoing
Benzene C6H6 2007-01-16 Ongoing
toluene C7H8 2007-01-16 Ongoing
ethane C2H6 2005-05-12 Ongoing
ethene C2H4 2005-05-12 Ongoing
propane C3H8 2005-05-12 Ongoing
propene C3H6 2005-05-12 Ongoing
i-butane i-C4H10 2005-05-12 Ongoing
n-butane n-C4H10 2005-05-12 Ongoing
i-pentane i-C5H12 2005-05-12 Ongoing
n-pentane n-C5H12 2005-05-12 Ongoing
n-hexane n-C6H14 2005-05-12 Ongoing
Wind Speed ws 1992-07-06 Ongoing
Wind Direction wd 1992-07-06 Ongoing
Temperature temp 2004-08-10 Terminated - 2004-09-07
isoprene C5H8 2007-01-16 Ongoing
Acetylene C2H2 2007-05-25 Ongoing

Carbon Cycle In Situ Observatory

Parameter Formula First Sample Date Status
Carbon Dioxide CO2 1976-01-01 Ongoing

HATS Flask Sampling

Parameter Formula First Sample Date Status
HFC-134a CH2FCF3 1994-11-29 Ongoing
HCFC-22 CHF2Cl 1991-11-26 Ongoing
Methyl Chloride CH3Cl 1993-11-09 Ongoing
HCFC-142b CH3CF2Cl 1992-02-11 Ongoing
Halon-1211 CBrClF2 1991-12-30 Ongoing
methyl bromide CH3Br 1993-11-09 Ongoing
HCFC-141b CH3CCl2F 1993-01-14 Ongoing
CFC-113 CCl2FCClF2 1991-12-30 Ongoing
dichloromethane CH2Cl2 1994-01-12 Ongoing
tetrachloroethylene C2Cl4 1993-12-15 Ongoing
carbonyl sulfide COS 2000-03-07 Ongoing
HFC-152a CH3CHF2 2000-08-09 Ongoing
Halon 1301 CF3Br 2007-01-12 Ongoing
Halon 2402 CBrF2CBrF2 1995-02-13 Ongoing
HFC-143a CH3CF3 2007-01-12 Ongoing
HFC-227ea CF3CHFCF3 2011-04-06 Ongoing
HFC-365mfc CH3CF2CH2CF3 2009-07-02 Ongoing
HFC-125 CHF2CF3 2007-01-12 Ongoing
HFC-32 CH2F2 2009-03-12 Ongoing
Methyl Chloroform CH3CCl3 1991-11-26 Ongoing

HATS In Situ Observatory

Parameter Formula First Sample Date Status
Nitrous Oxide N2O 1998-12-08 Ongoing
Sulfur Hexafluoride SF6 1998-12-03 Ongoing
HCFC-22 CHF2Cl 1999-02-16 Ongoing
CFC-12 CCl2F2 1998-12-08 Ongoing
Methyl Chloride CH3Cl 1999-01-28 Ongoing
HCFC-142b CH3CF2Cl 1999-01-28 Ongoing
Halon-1211 CBrClF2 1999-03-02 Ongoing
CFC-113 CCl2FCClF2 1998-12-03 Ongoing
carbon tetrachloride CCl4 1998-12-08 Ongoing
Methyl Chloroform CH3CCl3 1998-12-08 Ongoing
CFC-11 CCl3F 1998-12-08 Ongoing

Aerosol Surface In-Situ

Parameter Formula First Sample Date Status
Light Scattering Coefficient σsp 1977-01-01 Ongoing
Light Absorption Coefficient σap 1977-01-01 Ongoing
Particle Number Concentration Nt 1977-01-01 Ongoing

Radiation In-Situ Observatory

Parameter Formula First Sample Date Status
Direct Beam 1976-01-01 Ongoing
Shortwave Global 1976-01-01 Ongoing
Diffuse 1995-08-21 Ongoing
Downward Longwave 1999-08-06 Ongoing

Surface Ozone

Parameter Formula First Sample Date Status
Ozone O3 1975-12-14 Ongoing

Dobson Total Ozone

Parameter Formula First Sample Date Status
Ozone O3 1975-12-18 Ongoing





Parameter Formula First Sample Date Status
Wind Speed ws 1976-01-21 Ongoing
Wind Direction wd 1976-01-21 Ongoing
Temperature temp 1976-01-05 Ongoing
Ambient Pressure press 1976-01-09 Ongoing
Relative Humidity rh 1976-01-06 Ongoing