The Power Experiment: Impact of Assimilation of A Network of Coastal Wind Profiling Radars On Simulating Offshore Winds In and Above The Wind Turbine Layer

Abstract

During the summer of 2004 a network of 11 wind profiling radars (WPRs) was deployed in New England as part of the New England Air Quality Study (NEAQS). We utilize observations from this data set to determine their impact on Numerical Weather Prediction (NWP) model skill at simulating coastal and offshore winds through data-denial experiment. This study is a part of the Position of Offshore Wind Energy Resources experiment, or POWER, a DOE-sponsored project (Banta et al., 2014) that uses National Oceanic and Atmospheric Administration (NOAA) models for two one-week periods to measure the impact of the assimilation of observations from 11 inland WPRs. Model simulations with and without assimilation of the WPR data are compared at the locations of the inland WPRs, as well as against observations from an additional WPR and a High-Resolution Doppler Lidar (HRDL) located on the Ronald H. Brown Research Vessel (RHB) that cruised the Gulf of Maine during the NEAQS experiment. Model evaluation in the lowest two kilometers above the ground shows a positive impact of the WPR data assimilation from the initialization time through the next 5-6 forecast hours at the WPR locations for 12 of 15 days analyzed, when offshore winds prevailed. A smaller positive impact at the RHB ship track was also confirmed. For the remaining three days, during which time there was a cyclone event with strong onshore wind flow, the assimilation of additional observations had a negative impact on model skill. Explanations for the negative impact are offered.