Measurements of the vertical column abundance of atmospheric hydroxyl (OH) have been made during the period 1987--1989 at the National Weather Service (NWS) station at Moen, Truk, Federated States of Micronesia (7 ¿N, 152 ¿E). A total of 384 independent data sets was obtained. Tropical OH abundance levels average about 22% above corresponding mid-latitude values, with OH levels during late winter and early spring up to 50% above those observed at 40 ¿N. Stratospheric wind and temperature data obtained from the daily NWS radiosonde data are examined for correlations with the OH results. ¿ American Geophysical Union 1990