RAINOUT RELATIONS ON SAMPLING NETWORKS o21 made for eight storms. These included cases of (1) thunderstorms, rainshowers, and steady rain and (2) storms of various rainfall volume, intensity, and duration. Results were similar to those obtained in 1963. In all storms a relatively strong association was indicated between the patterns of beta deposition and storm rainfall with high and low centers of deposition lying near corresponding high and low centers of rainfall. The association between patterns of beta concentration and storm rainfall was relatively strong in six of the eight storms but was similar to the association observed ‘n 1963; the association between high and low centers was not consistent. Generally, high beta concentrations corresponded with light rainfall amounts, but exceptions were even more frequent than in 1963; that is, it was not uncommonto find high beta concentrations located near areas of high rainfall amounts. In summary, pattern comparisons among beta concentration, beta deposition, and storm rainfall on several networks in 1962-1964 indicate a generally strong association between patterns of deposition and rainfall if allowance is made for small displacement in the location of corresponding high and low centers. The causes of these displacements can be only hypothesized at this time. The correspondence between beta concentration and rainfall patterns is better than correlation of these two factors at a given point indicates, but the relation is not strong enough to permit the use of storm rainfall as a single predictor of beta-concentration patterns. Close association was found frequently enough, however, to indicate that rainfall volume has a strong influence on the beta-concentration pattern and that it should be studied further in conjunction with other meteorological factors that may help define the rainout patterns. REFERENCES 1, F. A. Huff, Study of Rainout of Radioactivity in Wlinois, Second Progress Report to Atomic Energy Commission, Contract AT(11-1)-1199, Illinois State Water Survey, January 1964. 2. R. L. Weatherford, Preparation of Samples for Radioactivity Counting, in Proceedings of the Second Sanitary Engineering Conference, Radiological Aspects of Water Supplies, University of Illinois Engineering Experiment Station Circular No. 69, January 1960. 3. A. Walton and Ralph E. Fried, Studies of Nuclear Debris in Precipitation, Seventh Progress Report to Atomic Energy Commission, Contract AT(30-1)2415, Isotopes, Inc., August 1961. 4, A, Walton, Micah W. M. Leo, and Colin Sanderson, Study of Rainout of Radioactivity in Illinois, Annual Report to Illinois State Water Survey, Contract AT(11-1)-1199, Isotopes, Inc., February 1963. 5. V. Conrad and L. W. Pollak, Methods in Climatology, pp. 54-55, Harvard University Press, Cambridge, Mass., 1950. 6. F. A. Huff and J. C. Neill, Rainfall Relations on Small Areas in Llinois, Illinois State Water Surv. Bull:, 44, 1957. 7. U. S. Weather Bureau, Thunderstorm Rainfall, Hydrometeorological Report No. 5, Washington, D. C., 1947. CDK

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