Attenuated backscatter profiles recorded by most automatic lidars and ceilometers (ALC) require absolute calibration during post-processing. Two methods utilising the probed atmosphere as a reference are available to derive absolute calibration coefficients: the Rayleigh method (e.g. Wiegner and Geiß, 2012) based on the molecular backscatter profile and the liquid cloud method (O’Connor et al., 2004) exploiting the attenuation by large droplets. Procedures for the implementation of these methods for diverse sensor networks have been developed in the framework of the previous EU COST action Toprof (e.g. Hopkin et al., 2019).
In this special working group meeting we are going to identify the necessary steps required to reach fully-automated calibration procedures. This includes a better understanding of the temporal variations identified in calibration coefficients for some ALC models.
The SWG is motivated by high demand for absolutely calibrated attenuated backscatter profiles across diverse sensor networks such as ACTRIS and E-PROFILE.
All meeting information can be found in the attachment :)
Hopkin, E., Illingworth, A.J., Charlton-Perez, C., Westbrook, C.D., Ballard, S., 2019. A robust automated technique for operational calibration of ceilometers using the integrated backscatter from totally attenuating liquid clouds. Atmos. Meas. Tech. 12, 4131–4147. doi:10.5194/amt-12-4131-2019
O’Connor, E.J., Illingworth, A.J., Hogan, R.J., 2004. A Technique for Autocalibration of Cloud Lidar. J. Atmos. Ocean. Technol. 21, 777–786. doi:10.1175/1520-0426(2004)021<0777:ATFAOC>2.0.CO;2
Wiegner, M., Geiß, A., 2012. Aerosol profiling with the Jenoptik ceilometer CHM15kx. Atmos. Meas. Tech. 5, 1953–1964. doi:10.5194/amt-5-1953-2012