This work provides a signal-processing and statistical-error analysis methodology to assess key performance indicators for a floating Doppler wind lidar. The study introduces the raw-to-clean data processing chain, error assessment indicators and key performance indicators, as well as two filtering methods at post-processing level to alleviate the impact of angular motion and spatial variability of the wind flow on the performance indicators. Towards this aim, the study mainly revisits horizontal wind speed (HWS) and turbulence intensity measurements with a floating ZephIR 300 lidar buoy during a 38 day nearshore test campaign in Pont del Petroli (Barcelona). Typical day cases along with overall statistics for the whole campaign are discussed to illustrate the methodology and processing tools developed.
Tiana, J.; Gutierrez, M.A.; Würth, I.; Puigdefabregas, J.; Rocadenbosch, F. IEEE International Geoscience and Remote Sensing Symposium p. 5379-5382 DOI: 10.1109/IGARSS.2015.7327051 Data de presentació: 2015-07-31 Presentació treball a congrés
This paper addresses a cardanic frame as mechanical-compensation device for a Doppler-wind lidar installed on a floating sea buoy as the “moving” lidar. From the methodological point of view, the horizontal wind speed (HWS) measured by both a reference lidar (i.e., “fixed”) and a floating lidar (i.e., “moving”) with and without a cardarnic frame is cross-examined by using standard statistical indicators and a compound pendulum model. Performance results are analysed both at laboratory level using a pitch/roll motion-simulation platform and at a sea-test measurement-campaign level some 250-m offshore Barcelona coast. Finally, simulations of the proposed pendulum-based model enables to tune-in and optimize cardanic-frame design parameters.
Gutierrez, M.A.; Tiana, J.; Bischoff, O.; Cateura, J.; Rocadenbosch, F. IEEE International Geoscience and Remote Sensing Symposium p. 2147-2150 DOI: 10.1109/IGARSS.2015.7326228 Data de presentació: 2015-07-28 Presentació treball a congrés
This paper departs from a preliminary near-shore measurement test campaign hold at El Pont del Petroli (PdP), Barcelona (Spain) where measurements from a Doppler wind-lidar buoy (the ”floating” lidar) are cross-examined against an on-shore reference lidar. From this framework the methodological analysis to intercompare two such lidars in terms of the retrieved Horizontal Wind Speed (HWS) - as key variable - is presented along with an overview of the signal-processing block diagram. Central to this work is to introduce the main error indicators (e.g., bias, RMSE, determination coefficient, absolute error and scatter plots) used to assess the performance of the floating lidar in the campaign. Finally, it is shown that even a basic smoothing procedure on the retrieved 1-s HWS time series is enough to enhance the determination coefficient against the reference lidar Turbulence Intensity (TI).