Cape Matatula

The American Samoa Observatory is located on the northeastern tip of Tutuila island, American Samoa, on a ridge overlooking the South Pacific Ocean. The observatory was established in 1974 on a 26.7 acre site as one of the NOAA/ESRL GMD Baseline Observatories.

The ALE/GAGE/AGAGE started measuring atmospheric CFC-11, CFC-12, CH3CCl3, CCl4, N2O in 1978, CFC-113 and CH4 in late 1985/early 1986, and CHCl3 in 1996 by using a GC-multidetector (GC-MD) system. A new Medusa GC-MS instrument was installed in May 2006. Both instruments are housed in the NOAA "Hudson" laboratory building adjacent to a 24-meter sampling and cellular telephone tower on the crest of edge. This station is especially important because it is the only in situ field measurement site where both the AGAGE and GMD networks overlap.

NOAA’s Global Monitoring Division also measures a range of ozone depleting substances and greenhouse gases at the American Samoa Observatory.

Station designation: 



14.2474º S, 170.5644º W

Station elevation: 

42 meters above sea level

Air intake elevation: 

35 meters above ground level

Station PI: 

Prof Ray Weiss (; Dr. Jens Mühle (

Station manager: 

NOAA SMO Station Chief/NOAA Corps Officer-in-Charge

Station team: 

Jooil Kim, Chris Harth, Roland Schmidt, Jen Gonzalez

Station email: 

Postal address: 

NOAA Samoa Observatory
P.O. Box 2568
Pago Pago, Cape Matatula, 96799, American Samoa

Station funding: 

Operation of the American Samoa observatory (SMO) is funded by the National Oceanic and Atmospheric Administration (NOAA) in the USA. AGAGE operations at SMO are funded by the National Aeronautics and Space Administration (NASA) in the USA.