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CELiS (Compact Eyesafe Lidar System) is an elastic backscatter light detection and ranging (lidar) system developed for monitoring air quality environmental compliance regarding particulate matter (PMk) generated from off-road use of wheeled and tracked vehicles as part of the SERDP (Strategic Environmental Research and Development Program) Measurement and Modeling of Fugitive Dust Emission from Off-Road DoD Activities program. CELiS is small, lightweight and easily transportable for quick setup and measurement of PMk concentration and emissions. CELiS operates in a biaxial configuration at the 1.5μm eyesafe wavelength with a working range of better than 6 km and range resolution of 5 m. In this paper, we describe an algorithm that allows for semi-quantitative PMk determination under a set of guiding assumptions using a single wavelength lidar. Meteorological and particle measurements are used to estimate the total extinction (α) and backscatter (β) at a calibration point located at the end range of the lidar. These α and β values are used in conjunction with the Klett inversion to estimate α and β over the lidar beam path. A relationship between β, α and PMk mass concentrations at calibration points is developed, which then allows the β and α values derived to be converted to PMk at each lidar bin over the lidar beam path. CELiS can be used to investigate PMk concentrations and emissions over a large volume, a task that is very difficult to accomplish with typical PMk sensors. |
