— UNCLASSIFIED ad to date as reports came in and an iso—intensity line of 0,1 r per day in the lagoon watéi“was also plotted on this chart, The surface and air radexes were plotted daily from weather data obtained from Aerology, Utilizing a vector analysis of the wind velocities, fall-out patterns for the surface, 15,000, 20,000, 25,000 and 30,000 feet were determined, These patterns were plotted on charts with a superimposed polar gria. From the fall-out patterns, the surface radex, given as two bearings from zero point, and also recommendations as to the direction of the third pass for each drone plane mother were determined. . Definite criteria were used to determine whether or not the day was operational from a radiolovical safety viewpoint. If the fall-out from 45,000 feet or below, did not extend between 90°T or 170°T fron zero point, the day was considered operational, If the fall-out from 45,000 feet fell on the bearing of Eniwetok-Parry islands (150°-160°) the day was considered questionable with moderate hazard, If the fall- out from 35,000 feet or below fell on these islands, the day was con- sidered non-operational, Three days preceding the test a forecast for a test day was made, and on the day before the test day the latest weather forecast was Pe data was prepared for the briefing. ae presented at 1800, Actual wind data was plotted at intervals from this time to 0300 at which time the last baleon sounding was made and the o “ A-RAY Plus Two — YORE Test Considerable radioactivity was found on the islands west of the test island, indicating extensive fall-out. Evidences of fall-out elsewhere were slight. A consolidated report was prepared and all the evidences of fall-out noted during the days following the test. On X-RAY-plus 5, Commander Task Group 7.6 sent a report to Conmander Joint Task Force 7 stating that the survey of all the perimeter islands had been completed, and recommended that long term closure of the islands from Yeirl westward to the southwest passage inclusive be instituted because of the radioactivity discovered along the beaches and the evidences of fall-out. The temporary clearance of the other islands and ‘of the™ lagoon beaches on these islands for swimming was recommended, Dust collectors had been set up on each of the principal ships of the Task Force, and were examined daily, together with a careful check of the evaporators, Several surveys were made on the test island and the gradual re~ treat of the iso-ihtensity lines was plotted in Radop. -he 50014920 UNCLASSIFIED "