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

American Samoa Observatory Tour
Around the Grounds: Hudson Building

The Hudson Building was completed December 1996. It currently houses the GMD Chromatograph for Atmospheric Trace Species (CATS) and the cooperative Advanced Global Atmospheric Gases Experiment (AGAGE) instruments for halocarbons, the Pollak for aerosols, the Dasibi and TEI monitoring surface ozone. The building is divided into three rooms. One contains an air compressor, the other two instruments. To see inside the Hudson Building continue down the page. (Photo by P. Roberts)

The NOAA ESRL/GMD CATS instrument. A four channel automated GC that runs 24 hours a day, 7 days a week. The instrument is currently operated to detect 14 species of halocarbons targetted specifically as climate forcing agents. For more information see (INSERT HATS PAGE HERE)
The cooperative AGAGE instrument. This GC also operates 24 hours a day, 7 days a week targeting similar species. The two systems are part of a scientific comparison.
Along with the CATS instrument are the TEI, surface ozone instrument, seen in the rack next to the gas cylinders, and the Pollak, aerosol monitor, to the left of the TEI. The black unit seen against the left wall is the pumping unit for Scripps Institute of Oceanography.for O2 flask monitoring.

Areas to visit:
[Samoa Home] [Observatory] [Hudson Building] [Observatory Rooftop] [Bluesky Tower] [Stairway & Point]