Mobile Lidar Technology for the Environmental Studies

The development of Micropulsed Doppler Lidars and deployment of these compact systems on mobile airborne, shipborne, and truck-borne platforms allows NOAA researchers to study dynamic processes in the atmospheric boundary layer in all regions, from urban areas to remote/inaccessible locations in complex terrain. Traditional in situ or stationary profiling observations cannot provide the flexible combination of spatial and temporal coverage that a fully capable mobile lidar allows. The analysis of the vertical, spatial, and temporal variability of wind flow variables (wind speed, wind direction, and turbulence) obtained during several recent experiments have been used for various air quality and weather applications including measuring the dynamics of wildfire plumes, understanding seabreezes, air-sea interaction processes, and study of upslope/downslope flows and urban heat islands.

Doppler lidar operations from a mobile platform requires addressing many challenges, such as an accelerating reference frame and vibration while in motion, that require thoughtful hardware design and data processing methods. A major obstacle to obtaining accurate wind profiles from the high-precision lidar measurements using these techniques is compensating for the pointing error and along-beam platform velocity that are due to ship motions, including those induced by wave action. To accomplish this, the lidar is equipped with a system that determines the orientation and motion of the platform and then actively stabilizes the pointing of the scanner and corrects the lidar velocity measurement by estimating and removing the platform motion component along the lidar pointing direction.

During the last 5 years, the NOAA/CSL mobile Doppler lidars successfully operated from various platforms providing unique measurements to characterize ocean and atmospheric processes, to study the complex flow of winds around wildland fires, and to better understand effect of a large wind farm on wind flows under different atmospheric conditions.