The publication documents the effort made to develop and evaluate a new methodology for estimating stability category using on-site meteorological data that can be automatically collected and logged, e.g., wind speed and solar radiation during daytime and temperature difference (Delta-T) at night. The new method (Solar Radiation/Delta-T, SRDT) uses 5 wind speed classes and 4 insolation classes during daytime, and 3 wind speed classes and 2 Delta-T classes during nighttime. To fulfill the objectives of the evaluation three on-site meteorological data bases were obtained: Kincaid, IL (4/80 - 8/80), Longview, WA (1/91 - 12/91), and Bloomington, IN (7/91 - 7/92). The data were pooled to yield 19,540 valid hours. Using the composite data, stability classification criteria were determined iteratively for the SRDT method. Stability categories via both methods were rigorously compared for all valid hours. Overall, stability categories coincided for 62% of the hours examined, and were + or - 1 class for 89% of the hours. The same criteria were then applied to each of the three sites individually to assess site to site variability. This variability was seen to be of the order of that seen within an individual site.

Author: C. Thomas Coulter. "October 1993." "EPA/454-R-93-055." Includes bibliographical references (pages 28-29).