Using Scanning Backscatter Lidar to Determine Planetary Boundary Layer Height
Information about the planetary boundary layer (PBL) height has a crucial importance, since it is the region of the lower troposphere where Earth’s surface strongly influences atmospheric parameters, such as temperature, moisture, and wind, through the turbulent transfer of air masses; therefore, it makes it a key parameter in air quality control and pollutant dispersion. Extensive lidar measurements to reveal tropospheric aerosol distribution and its microphysical properties have been realized between 2009 and 2015 at the Gebze station of TÜBITAK Marmara Research Centre (MRC) in Turkey. The lidar system is based on an Nd:YAG laser with its second and third harmonics to measure three backscatter and two extinction coefficients from which particle microphysical parameters such as number, area and volume densities, effective radius, complex refractive index and polarization can be retrieved. The addition of the scanning module to the existing system allowed us to determine the PBL height in larger areas by making scanning measurements with 20° to the horizontal. So, instead of the conventional single column measurements made by the synergistic measurements done by several measurement systems together with the coexistence of a lidar, a scanning lidar system was used to cover wider ranges.
Keywords: Nd:YAG laser, lidar, planetary boundary layer (PBL), scanning, height