Weather Bureau Research Station, Mauna Loa Observatory (MLO), at an elevation of 11,150 ft. on the north slope of Mauna Loa, Hawaii, was dedicated in July 1956 and assigned a permanent staff one year later, in preparation for the International Geophysical Year.

The historical background, physical setting, and facilities of the Observatory are described and the many and diverse scientific uses made of the site in the nearly six years of its existence reviewed. MLO's present effort lies principally in the continuous monitoring of solar radiation, carbon dioxide, total and surface ozone, and the meteorological elements, and in the analysis and interpretation of the data. Ice nucleus counts have been made during local volcanic eruptions and for other periods ranging from several weeks to a year or more. An extensive program in atmospheric electricity was recently completed. The motions and properties of the atmospheric envelope about Mauna Loa are being explored as a key to interpreting the observations made within it.

The Observatory's major advantages for a variety of studies in the geophysical and space sciences lie in its elevation, its freedom—due to the underlying trade inversion—from most of the water vapor and other turbidity of the lower troposphere, and the consequent exceptional transparency of the overlying atmosphere. It offers, in addition, an equable climate the year around and a base station for work done at the summit of Mauna Loa, 2500 ft. above.

More important than any of the foregoing, however, may be MLO's possession of an atmospheric environment that has little prospect of debasement through the encroachment of population or industry. This endowment makes the Observatory of inestimable value as a vantage point from which to maintain a careful surveillance of the significant indices of global atmospheric change.