Curating the TD6405 database of 1-min interval wind observations across the USA for use in Wind Engineering studies

Abstract

The TD6405 online database of wind observations at 1-min intervals from 2000 onwards at almost 1000 stations across the USA is a highly valuable on-demand resource for Wind Engineering studies, but it contains numerous defects. Many defects are common to other observational databases, for which detection and repair methods already exist. Others are unique to TD6405 for various operational reasons, including the requirement for real time quality control and the adoption of sonic anemometers. Having no moving parts, sonic anemometers provide ideal perches for birds which interrupt the observations and create spurious large gusts on landing and take-off. The real time quality control test added in 2013 to excise bird-generated gusts is shown to miss many of them and to generate four false positives for each one it does find. Each false positive also removes the following 5-min period of valid observations. Consequently, after 2013, the incidence of calms is suppressed, and thunderstorm downbursts are disproportionally censored in light winds. An efficient retrospective test is proposed and validated using observations prior to 2013, but the data missing after 2013 is permanently lost and cannot be recovered. Urgent action is required to correct this ongoing situation.