Received: 26 Oct 2020 – Accepted for review: 19 Dec 2020 – Discussion started: 22 Dec 2020
Abstract. While the wind farm parameterization by Fitch et al. (2012) in Weather Research and Forecasting (WRF) model has been used and evaluated frequently, the Explicit Wake Parameterization (EWP) by Volker et al. (2015) is less well explored. The openly available high frequency flight measurements from Bärfuss et al. (2019) provide an opportunity to directly compare the simulation results from the EWP and Fitch scheme with in situ measurements. In doing so, this study aims to compliment the recent study by Siedersleben et al. (2020) by (1) comparing the EWP and Fitch schemes in terms of turbulent kinetic energy (TKE) and velocity deficit, together with FINO 1 measurements and Synthetic Aperture Radar (SAR) data and (2) exploring the interactions of the wind farm with Low Level Jets.
Both the Fitch and the EWP schemes can capture the mean wind field in the presence of the wind farm consistently and well. However, their skill is limited in capturing the flow acceleration along the farm edge. TKE in the EWP scheme is significantly underestimated, suggesting that an explicit turbine-induced TKE source should be included in addition to the implicit source from shear. The position of the LLJ nose and the shear beneath the jet nose are modified by the presence of wind farms.
For the first time, turbulence kinetic energy (TKE) calculated from the explicit wake parameterization (EWP) in WRF is examined using high frequency measurements over a wind farm, and compared with that calculated using scheme from Fitch et al. (2012). We examined the effect of farm-induced TKE advection in connection with the Fitch scheme. Through the case study with Low Level Jet (LLJ), we analyzed the key features of LLJ and raised the issue of interaction between wind farm and LLJ.
For the first time, turbulence kinetic energy (TKE) calculated from the explicit wake...