INPUT DATA Surface meteorological observations were avaltiaole from some atolls and from the U.S.S. Curtiss which cruised south of Bikini; however, since the larger particles fall rapicly from the debris cloud to tne surface and spend little time near the surface, not many surface reports were used. Of far greater importance are the upper air wind observations taken at four sites near Bikini atoll. Other significant input data consisted of a flat topography, cell sizes of 34 km (east-west) by 17 km ‘north-south}, and 1 km in the vertical, stem and cap debris cloud geometries at Stabilization time, source rates for both gross fission produets and selected individual nuclides, and particle size spectrum parameters. CALCULATIONS Geoss Fission Products Tne time-integrated external dose pattern (in rads} due to gross fission oroducts from detonation time to evacuation time of Rogelap atoll (51 hours) ure shown in Fig. 1. Tne numbers next to Ailinginae, Rongerix, and Utirik atolls are integrated values uo to the time people were evacuated from those atolls. For comparison, the value Strausst®! are given in Table 1. of total dose, Note that . estimated by . [3 Dunning. j and the agreement is very good for Rongelap and Ailinginae atolls. However, calculations for Rongertk and Utirik ave at odds with earlier estimates. The code calculations for Rongerik are higher, while those for Utirik are lower. This variation appears to be in part a prablem of "tuning"; also a possible variation in wind directions and speeds at late times when the only wind observations were from the U.S.S. Curtis, south of Bikini (some distance from the atolls of concern) may be an explanation.

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