Multi‐LiDAR Observations of Coastal Atmospheric Duct Evolution in Hampton Roads

Abstract To better understand the influence of atmospheric ducts on radio frequency (RF) operations, continuous high‐resolution observations of temperature and water vapor are essential. Hampton University's (HU) 48‐inch Raman‐Mie LiDAR provides such measurements through rotational and vibrational Raman techniques, enabling detailed monitoring of refractivity gradients that drive duct formation. In this study, we analyze a strong coastal ducting event from the evening of 22 May to the morning of 23 May 2019 over Hampton, Virginia, using a multi‐LiDAR data set that combines Raman‐Mie thermodynamic profiles, US Army Combat Capabilities Development Command (DEVCOM)‐Army Research Laboratory (ARL) Doppler LiDAR wind fields, and NASA Langley micropulse LiDAR (MPL) aerosol and cloud observations. Results show that ducts developed between 200 and 330 m in association with the transition from a post‐frontal cold air mass to a warm front. Water vapor depletion, rather than temperature inversion alone, was the primary driver of negative refractivity gradients. Wind shear was found to contribute to the persistence of a dry layer above the boundary layer, which in turn supported the formation of the duct. Doppler LiDAR further revealed that low‐level jets (LLJs) elevated and weakened ducts through turbulent mixing, in some cases splitting them into two distinct layer processes rarely captured in previous studies. This case study demonstrates, for the first time in a coastal setting, how multi‐LiDAR synergy resolves the fine‐scale thermodynamic and dynamical processes that govern duct evolution. These findings highlight the importance of sustained, high‐resolution coastal monitoring for improving refractivity forecasts and mitigating radar propagation uncertainties in littoral environments.