At the request of the Washington Department of Highways two studies have been conducted by a team of specialists at the University of Washington Air Resources Program to determine the applicability of the Acoustic Radar to air quality modeling of mobile sources. Following an exploratory investigation, a comprehensive study was undertaken in which the atmospheric structure was measured by a modified Monostatic Acoustic Radar and the derived stability conditions were compared with the commonly used Pasquill-Turner stability classes, which are based on empirical data. This comprehensive study was performed over a three month period in the fall of 1976, when an unusually persistent air stagnation existed in the study area caused by a stationary high pressure system over the entire Northwest. The Evergreen Point Floating Bridge Toll Plaza in Bellevue, Washington was selected for test location.
The carbon monoxide (CO) concentrations were measured at six strategically located sampling points and then compared with the computer model predictions utilizing atmospheric stability data derived by both the Pasquill-Turner and the Radar Echo methods. The results indicated that the Acoustic Radar method of determining D & E stability classes is a more realistic approach than that of the Pasquill-Turner Method. Furthermore, the Radar method can also provide continuous remote sensing and recordings of atmospheric parameters.
The variation of the inversion height, as measured by the Radar echoes has shown a reasonably good correlation with the variation of the measured CO concentration.