Comparisons of airborne lidar measurements of ozone with airborne in situ measurements during the 1995 Southern Oxidants Study

As part of the 1995 Southern Oxidants Study (SOS), the National Oceanic and Atmospheric Administration airborne ozone lidar was deployed during June a nd July to provide detailed three-dimensional lower tropospheric ozone dist ribution information in the Nashville, Tennessee, area. The airborne portio n of the study included six aircraft instrumented with an assortment of in situ and remote sensors. Results of comparisons between the ozone values ob tained using the lidar and the values obtained using in situ instrumentatio n aboard other aircraft are presented. High resolution (90 m vertical and 5 20 m horizontal corresponding to 8 s at a flight speed of 65 m/s) was maint ained during the analysis of the lidar data which caused statistical variat ions in the calculated ozone concentrations from 3 ppbv (5% for typical ozo ne concentrations encountered during the study) at a range of 1500 m from t he lidar to 11 ppbv (17%) at a range of 2500 m from the lidar. However, the lidar ozone concentration measurements compare favorably with the in situ values, with the average offset less than 10 ppbv (16%) for each flight, an d the average magnitude of the offsets over all the flights at 4.3 ppbv (7% ).