® @ A111 Greenhouse-Dog Shot. The rise time on KING was, however, much faster than for MIKE. As in the case of MIKE, this reduction in peak pressure appears to be a refraction effect; the measurement is of little or no value for : 2 - determining a yield quickly. : Surface Kffects : Qf the several laboratories particppating in blast measurements on ie KTaO, only preliminary data from Sandia Corporation are available at the : present time. Nonetheless, their results seem clear enough to justify ‘ ecae conclusions. BEST AYAILASLE COPY In caver to compare the blast wave over relatively ideal and a rela- ; tively poor surface, two blast lines were instrumented by Sandia, one Lins s over water on the subwirged reef, the other line through the center of Aunit. | : It was expected that the rise tines would de fast over water, ani pressures : close to ideal; the rise times would be alow over land, and the "therml” . a curves of LA-1406 be applicadle. :. a time recorés amply confiraed this prediction. On water stations spproxi- 3 - mmtely 5500 feet and 6500 feet fron sero, the pressures are. nearly ideal, 4 Preliminary readings of Sandia's pressure- ‘ i: with fast rise tines) on the other hand, an even more distent land station, 3 about 7450 feet, had @ very long rise time, and peek pressure cocsiderably | Duster-Tusbler-Ivy series, al) of which amply confirm the theory of surface : = below ideal values”. ‘he Ivy test is then the logical ecupletion of the x7 effects proposed in bbwWh06 and other payers during the past year’. aa * Meanwhile, these records have been more carefully exmmined by Sendia. i7 ee Cox xeparts the seme general conclusion, “the rise times are faster, and a6 the pressures higher over vater than over land", ’ :