In March of 2017 the terrestrial instrument system (TIS) team identified that the 2D anemometers on the NEON towers were producing 2D wind data that did not correlate with 2D wind data collected at NEON meteorological stations nearby. At first this was assumed to only be an issue at a handful of sites. However, as time progressed it was evident that this was an issue at nearly all operational sites. The North Transducer head of the 2D anemometers at the TIS sites listed below were not oriented consistently and all 2D wind direction data were offset from 90 to 270 degrees from 'truth'. The deviation from truth is a function of site and measurement level. The TIS team is in the process of identifying site- and measurement-level--specific dates of incorrect anemometer orientation so that these data can be corrected. The process of identifying the orientation of each 2D anemometer, the corrective action, and reprocessing the data should be completed by Spring 2020. We will provide a more specific completion date in February 2020. Please use the data portal contact form for further inquiries; please select DP1.00001.001 in the Data Product dropdown list and include the term "INC0033824" in the body of your request.