Dual-Doppler Radar Characterization during the Krummendeich Field Experiment: A Campaign Overview and Performance Assessment

Abstract. The Krummendeich campaign in northern Germany was a field experiment designed to test dual-Doppler radar (DDR) technology for resolving flow fields. The campaign took place at the WiValdi research wind farm containing two operating turbines. Throughout the measurement period, a comprehensive observational network consisted of DDR, scanning and profiling lidars, a microwave radiometer, a meteorological mast, and laser disdrometers. Capitalizing on these datasets, the study herein offers an overview of the campaign while demonstrating the utility of the DDR method as a wind measurement tool for wind energy applications, specifically. This is done through validations against a co-located Doppler scanning lidar, assessments of data availability across meteorological conditions, and analyses of the method's capability to resolve flow features, i.e., turbine wake signatures. The site's temperate maritime climate, marked by frequent precipitation and wind direction-dependent stability regimes, provided a naturally diverse atmospheric environment for testing the method across conditions relevant to central European wind energy deployments. Validation showed great agreement with scanning lidar across most height levels, with discrepancies mainly occurring at near-surface levels. Hydrometeor presence strongly governed data availability, where precipitating periods sustained near-complete domain coverage. While radar returns were occasionally affected by artifacts even during otherwise well-covered scans, the method successfully captured both low-level jet and turbine wake within its flow field. Together, these results performance verification contribute to a continuously growing body of evidence supporting DDR as a viable and scalable tool for wind energy research and industry, with plans for deeper analysis and additional fieldwork to follow.