The long term stability of lidar calibrations

Wind lidars are now used extensively for wind resource measurements. One of the requirements for the data to be accepted in support of project financing (so-called ‘banka-bility’) is to demonstrate the long-term stability of lidar cali-brations. Calibration results for six Leosphere WindCube li-dars are used examine this stability.

Calibration results be-fore and after periods of field service are examined. No evi-dence of systematic drift is observed but some significant statistical variation is seen. We believe that much of the cal-ibration variation is due to differing environmental parame-ters pertaining in the different calibration periods.

This is supported by sliding-window analyses of one lidar at one location where the same order of variation is observed as between pre-service and post-service calibrations.