# Can LiDARs Replace Meteorological Masts in Wind Energy?
## 1 Introduction
Wind energy applications also require that the measured wind data is further processed to produce distributions of wind speed and power output so that the wind energy potential of the site can be evaluated. Neither the above studies nor other related literature reported any such analyses. The current study employed a long-term measurement campaign and has not filtered out data based on wind direction or wind speed range etc., which allow for a more realistic evaluation of the LiDAR technology. Furthermore, the accuracy of LiDAR in estimating the power potential of the site is also discussed. It should also be noted that both the VAD and DBS techniques employed in the above measurement campaigns assume horizontal homogeneity over the area at the measurement heights. Such an assumption is not valid for complex terrains and thus results in higher uncertainty in the measurements [11]. Considering the large wind energy potential of coastal and offshore sites, more recent investigations focused on the assessment and analysis of coastal and offshore wind resources. The readers are referred to [PERSON] et al. [12] for existing research and recommended practices for offshore wind speed measurements using in situ and remote sensing technologies. In this regard, [PERSON] et al. [13] conducted a LiDAR-based measurement campaign in a coastline area to investigate changes in wind speed and turbulence level when the wind transitions from onshore to offshore wind or vice versa. LiDARs have also been employed for measurements of atmospheric turbulence. [PERSON] and [PERSON] [14] and [PERSON] et al. [15] have presented extensive reviews on the application of LiDARs for turbulence measurements. While turbulence estimation using wind radar was performed as early as 1970 [16], most studies on LiDAR-based turbulence measurement were conducted in the past 10-15 years [14]. [PERSON] [16] was the first to employ the VAD technique to measure the components of the Reynolds stress tensor in snow conditions. Later on, other researchers further improved this method to get better estimates of the error in the measured data [17; 18]. More recently, [PERSON] et al. [19] investigated the influence of spatial volume averaging on LiDAR-based turbulence measurements. [PERSON] et al. [20] investigated a method to measure the vertical flux of horizontal momentum in and above the atmospheric surface layer. [PERSON] [21] used the DBS mode to measure wind speed and compared it against sonic and cup anemometer measurements. They showed that LiDAR-measured turbulence intensity was higher than that measured with a cup anemometer but lower than the sonic anemometer measurement. The above studies used a single LiDAR to estimate turbulence, which means they have to assume that the flow is horizontally homogeneous at each height. It is believed that this assumption would lead to turbulence measurements with high errors. Therefore, multiple studies employed triple LiDARs to measure the 3D turbulence at a point in space [22; 23]. These results agreed well with reference measurements from tower-mounted sonic anemometers. The method is gaining popularity among wind energy researchers and was employed in other studies as well [24]. While the triple LiDAR scan method will be more reliable compared to VAD and DBS techniques, deploying three LiDARs can significantly increase the cost, thus making this approach less attractive for the wind energy developer. Furthermore, suitably positioning three LiDARs in complex terrains or sites with natural or man-made obstacles can pose a major challenge. If LiDARs are to replace meteorological masts, they should be able to measure wind speed and turbulence with a sufficient degree of accuracy for long periods of time. Therefore, the objective of this study is to answer the question of whether a single profiling LiDAR can replace the meteorological mast in a moderately complex terrain, without having to make major compromises in terms of accuracy or data availability.