A Note on Fallout Prediction

This paper outlines a study made to determine the requirements of the Army in the field for fallout prediction. A series of operations analyses that depict graphically the fallout event for various yields and wind fields as it develops on tactically deployed Army forces have been performed to (1) confirm countermeasures that minimize the influence of fallout on tactical operations, (2) indicate the predicted information required by tactical commanders to allow effective application of these countermeasures, and (3) determine the accuracy requirements associated with this predicted information. The principal analysis tools used are overlay representations of tactically deployed Army forces, and template representations of the U.S. Naval Radiological Defense Laboratory's Dynamic Fallout Model. The results of application of countermeasures to fallout by tactical commanders have been determined and compared for two conditions (1) No Predicted Information (knowledge only of time and location of burst, and readings from radiac instruments) and (2) Perfect Predicted Information (knowledge of the predicted development of the fallout field in time and space as derived from the USNRDL D-Model). From this comparison, areas are identified where prediction offers a distinct advantage to the tactical commander, the most important elements of the predicted information are deduced, and then prediction accuracy requirements are defined. Finally, an operationally useful prediction concept is suggested.