Doppler Lidar Data Products Released for BNF Observatory

Published: 17 June 2025

Arrows indicate wind direction, and colors represent wind speeds from 0 to 30 m s^-1 at heights from 0.0 to 3.0 km. — Time-height displays of DLPROF-WIND data show wind speed and direction at the Bankhead National Forest (BNF) main site on March 13, 2025. Images are from Rob Newsom, Pacific Northwest National Laboratory.

Value-added products (VAPs) providing horizontal wind profiles and vertical velocity statistics from Doppler lidar data are now available for the Atmospheric Radiation Measurement (ARM) User Facility’s Bankhead National Forest (BNF) atmospheric observatory in northern Alabama.

The Doppler Lidar Wind (DLPROF-WIND) VAP produces daily files containing profiles of wind speed and direction. The Doppler Lidar Vertical Velocity Statistics (DLPROF-WSTATS) VAP produces daily files containing height- and time-resolved estimates of vertical velocity variance, skewness (asymmetry), and kurtosis from vertically pointing measurements. DLPROF-WSTATS also provides estimates of cloud base height and cloud base vertical velocity.

Currently, the BNF operates one Doppler lidar each at the main site and the Courtland and Double Springs supplemental sites. During standard operations, each Doppler lidar performs plan position indicator (PPI) scans once every 15 minutes and stares vertically the rest of the time. Radial velocity measurements from the lidar are used to derive profiles of horizontal winds from the PPI scans and vertical velocity statistics from the vertical staring data. Doppler lidar scan strategies may be temporarily changed during field campaigns to support the science objectives of the campaigns.

DLPROF-WIND processes each PPI scan acquired during a given day to produce time- and height-resolved measurements of the horizontal winds. The height resolution of the output is typically about 26 meters, and the time resolution depends on the frequency with which the PPI scans are performed. Each PPI scan takes approximately 30 seconds to complete, which means the resulting profiles represent 30-second snapshots of the atmosphere taken once every 15 minutes.

Time-height displays of DLPROF-WSTATS data show (a) vertical velocity variance from log( [m^2 s^-2]), (b) skewness from -3 to 3, and (c) kurtosis from 0 to 6 at the BNF main site on March 13, 2025. The heights of all plots range from 0 to 4 km. — Time-height displays of DLPROF-WSTATS data show (a) vertical velocity variance, (b) skewness, and (c) kurtosis at the BNF main site on March 13, 2025.

In addition to the wind measurements, the VAP provides estimates of the random uncertainty in wind speed and direction. These uncertainties provide a useful metric for quality control of the wind measurements.

DLPROF-WSTATS computes vertical velocity statistics from 1 Hz vertical staring data using a 30-minute averaging interval. The vertical resolution of the output is typically 30 meters, and the true time resolution is 30 minutes. The output is oversampled at 10-minute intervals.

More information about the VAPs can be found on the DLPROF-WIND and DLPROF-WSTATS web pages. Descriptions of algorithms used to generate the products, their input and output, and data quality control procedures are available in the DLPROF-WIND and DLPROF-WSTATS technical reports.

Access the DLPROF-WIND and DLPROF-WSTATS data in the ARM Data Center. (To download the data, first create an ARM account.)

For questions about these VAPs, please contact ARM translator Damao Zhang, Doppler lidar instrument mentor Rob Newsom, or VAP developer Gabriel Gibler.

To cite the DLPROF-WIND data, please use doi:10.5439/1178582. To cite the DLPROF-WSTATS data, please use doi:10.5439/1178583.

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ARM is a DOE Office of Science user facility operated by nine DOE national laboratories.