0021620 San in which M2(t) is the value of the mass contour ratio for a surface detonation, a, is the ratio Ao/Ay, where A, is the crater mass scaling coefficient for surface detonations (see Eq. 10) and A, is the crater mass scaling coefficient for detonations at the scaled depth, A (A = . . . » ~ le depth of burst in ft/(yield in lbs of TNr)+/3); the ratio, a), is the mass correction factor to a surface detonation; for air bursts, has values that are greater than 1.00; and, for underground bursts, a, has values that are less than 1.00. Possible effects of the particle size and specific activity on the mass contour ratio were mentioned in Section 3.3. The ratio,.as defined, is concerned only with the total activity per unit area and the total particle mass per unit area at a given location. Thesé can be estimated by use of fallout model computations if both the activity and mass distributions are known as a function of particle size. The particles that carry the radioactive material back to earth are composed essentially of the environmental materials at the shot point. For near-surface bursts, the types of materials of most interest are native soils (to several hundred feet in depth), seawater, and mix- tures of material original example, the two for harbor detonations. If the mass of the original is scalable with weapon yield, then the equivalent mass of the material must be used in the contour scaling functions. For the fallout from detonations in seawater will consist origin- ally of seawater which, as drops or ice particles, will change in size during their fall time due to evaporation or condensation of the water. If they dry completely, the final residual mass would be about 3 4% of the original seawater mass. In this case the original composition may be determined on the basis of the seawater mass and, if the contour ratios are point functions, the value of the ratio at a location will depend on how the evaporation takes place in space and time. DOE/NW Meteorological factors are of major importance in the distribution of the fallout from the time that it is formed. Although the scaling functions discussed in this report are only concerned with the contaminated system after the fallout has been deposited, the discussion in Section 3.3 showed that the wind speed was involved when the activity was taken as varying with the square of the particle diameter. Thus the factors that influence the distribution of the fallout may indirectly influence the value of the contour ratios if the latter are point func- tions. The effect of the inclusion of nonscalable or extraneous debris in fallout on the mass contour ratio, as previously mentioned, would result in high apparent observed values of the mass contour ratio. Ze i> Hy 14 od te wn ” a, :