Daily fluctuations of radioactive fallout particles in ground-level air

Abstract

Long-range 500 mb and 300 mb air trajectories were computed in an attempt to interpret the daily variation of the number of fallout particles in the ground-level air observed at Fayetteville (3eoN, 94"W), Arkansas, after a nuclear weapon was tested at Lop Nor (40"N, 9O"E), China, December 24, 1967. The dates of occurrence of peak concentrations of fallout particles generally coincided with (a) the arrival times of air masses at 500 mb and/or 300 mb after completing a cycle around the world, and (a) the passage of 500 mb troughs at Fayetteville. A significant deviation from the above rule occurred on January 20, 1968, when the highest concentration of fallout particles in air was observed a t Fayetteville. According to the computed air trajectories, such a maximum should have occurred 3 days earlier on January 17, 1968. The discrepancy was explained as due to local meteorological conditions: the occurrence of positive vorticity transport at 500 mb followed by the formation of slow-moving cutoff low during January 17 through January 19, 1968.

Unusual Nuclide Concentrations in Air after the 1986 Chernobyl Event

“…It was determined in the 1960's that debris injected into the atmosphere by Chinese nuclear test explosions circled the world in 3 to 4 weeks [6 -9], Chen et al [10] computed long-range 500 mb and 300 mb air trajectories in an attempt to interpret the daily variation of the number of fallout particles in the ground-level air observed at Fayetteville (36°N, 94°W), Arkansas, after a nuclear weapon was tested at Lop Nor (40 °N, 90Έ), China, on December 24, 1967. Their results indicated that the nuclear debris were circling the world in about 10 days and 17 days at the 300 mblevel and 500 mb-level, respectively.…”