1 aCA PREFACE Although weather observations have for many years been obtained on various oceanic islands, many fundamental questions concerning the local climates and microscale weather on such islands remain unanswerede In particular, the problem of to what extent an oceanic atoll creates its own local weather and microclimates has not been satisfactorily resolved. Is there signifi- cantly more rainfall upon an atoll] than there would be were the atoll replaced by open ccean? Are there significant differences in air temperature between the windward and leeward sides? With a large deep lagoon like that at Eniwetok, is the heat exchange between lagoon water and air essentially the same as the exchange between water and air over the ocean nearby? and other questions have long given rise to considerable controversy. These The present study was undertaken to provide at least somewhat better answers to such questions than have heretofore been possible. Initial impetus for this study was provided by Professor Maxwell S. Doty of the Department of Botany, University of Hawaii. Professor Doty had been conducting phytoplankton productivity Studies at Eniwetok and wished to know whether there were significant differences in mean rainfall from one to another part of the atoll. He suggested to the authors that it might be worthwhile to establish raingages at several different sites and obtain comparative rainfall readings over a period of at least a years After Several discussions among Professor Doty and the authors, it was decided to carry this suggestion still further and to obtain observations of several different kinds on a micro-scale. Accordingly, a field plan was worked out and the Eniwetok Microclimatic Project was formally established under the joint auspices of the University of Hawaii ((under AEC Contract No. AT-(O04-3)-15)), Us. Ss Weather Bureau, and Joint Task Force SEVEN. The period of investigation was chosen so as to derive maximum possible support from Task Force operations planned for the spring and Summer of 1958. Operation HARDTACK was conducted during this period; The nuclear test series known as and during the build-up for these tests as well as during the test period itself it was possible to draw on logistic and meteorological Support not usually available at Eniwetok. SERS Swear comers geo 4 “" 7 ene = Sree or one “gee