A ZephIR continuous wave (CW) lidar has completed 40 months of continuous operation during which time no maintenance or servicing has been conducted on the ZephIR.
A 91m IEC compliant mast at the UK’s Remote Sensing Test Site (Pershore, UK) was used to compare pre and post deployment validations from the ZephIR which demonstrated that there was also no need for re-calibration on ‘return-to-base’. Analysis of the results concluded that any changes in accuracy over the period are insignificant and much less than 1%; well within the industry IEC standard requirement for accuracy which is of the order of 1.5% to 2.0% depending on wind speed for a first class, calibrated, well-mounted cup anemometer. ZephIR does not require re-calibration and this latest deployment demonstrates the system’s performance stability over time. As per IEA Wind recommendations for ground-based vertically profiling remote sensing for wind resource assessment, a periodic verification or validation for Remote Sensing Devices (RSDs) should be performed after every two years or more frequently if specified by the manufacturer. Following initial deployment in September 2010 the ZephIR in this case continuously acquired wind profile data until February 2014. Due to operational constraints associated with the specific deployment, it was not possible to recover the device for inspection and service within the recommended service interval.
