Validation of Turner Workbook normalized air exposure predictions for surface level releases using Hanford dispersion data. [R]

In general, the methods used to determine atmospheric stability in assessment models depend upon the personal needs of the assessor. However, the results of this study indicate that for conditions similar to those prevailing during the Hanford tests and for the assumptions used with the Turner Workbook calculations, a method of atmospheric stability determination based on the vertical temperature gradient should be used if the assessor desires to insure some conservatism in his calculations of Eu/Q. On the other hand, a more realistic estimate of Eu/Q can be obtained using a method based on sigma/sub theta/, recognizing that a tendency still exists to overpredict Eu/Q. An additional approach to improve model predictions would be to apply the linear regression parameters shown in Table 4 to predictions based on the vertical temperature gradient methods. Application of the regression parameters to adjust the predictions is feasible because of the relatively high correlation between measured and predicted value exhibited by all three methods of stability determination.