Lidar Banner

Field Project: CASES-99

Principal Investigators: Robert Banta and Rob Newsom
HRDL out in a flat field
HRDL at the CASES-99 field site outside Leon, Kansas

The Cooperative Atmosphere and Surface Exchange Study (CASES-99) field observation program was designed to investigate events in the nighttime stable boundary layer (SBL), and to study physical processes associated with the morning and evening transition periods. The overall effort encompassed observation, data analysis, and numerical modeling to achieve an understanding of episodic events that populate the SBL. The SBL, or the atmospheric boundary layer that forms over a cold surface, occurs at night over land. It thus occupies about half of the diurnal cycle, yet transport, fluxes, and other processes in the SBL are poorly understood and often assumed to be negligible.

The Cooperative Institute for Research in the Atmosphere (CIRA) at Colorado State University (CSU) in cooperation with the Environmental Technology Laboratory/NOAA (ETL/NOAA) deployed ETL's High Resolution Doppler Lidar (HRDL) to the CASES-99 field site near Leon, Kansas. The experimental period was October 1-31, 1999. During this time, HRDL recorded approximately 200 hours of data during 23 days of operation, including 12 intensive operation periods (IOPs). Funding for the deployment and follow-on data analysis was provided by the Army Research Office, the Center for Geosciences/Atmospheric Research (CG/AR) at Colorado State University, and the National Science Foundation (NSF) (Grant # ATM-9908453).

The objectives of the HRDL deployment were:

  1. To use the analysis of HRDL data in coordination with other measurements, including surface-flux stations, boundary-layer profilers, radars, high-resolution radiosondes, tethered balloons and kites, to understand the roles of
    1. gravity waves
    2. turbulence structures
    3. low-level jets
    4. local drainage currents
    in modulating or controlling transport and fluxes near the surface under stable conditions.
  2. To obtain 3-D lidar datasets to evaluate the potential of four-dimensional variational data assimilation (4DVAR) techniques for single-Doppler wind retrieval, LES initialization, and fundamental boundary-layer research.

The extensive array of in-situ and remote sensing instruments, including HRDL, provided unprecedented spatial and temporal resolution of SBL processes. On going analysis of the CASES-99 dataset will lead to better estimates of heat, momentum, and trace-species fluxes through the boundary layer, and to improved parameterizations of these fluxes in numerical models.

CASES-99 HRDL datasets

Raw radial velocity and intensity data acquired by HRDL during the CASES-99 IOPs are available through the Joint Office for Science Support (JOSS) site. These data are stored in netCDF, and have been subjected to minimal quality control.
Vertical profiles of mean horizontal winds have been computed from the HRDL dataset. These data are stored in ASCII format, and are available by clicking here. Click here to see a photo gallery of CASES-99 HRDL pictures.

To view selected samples of data, click on the desired day in the calendar below. Please note, all dates and times are given in Universal Coordinated Time (UTC). To convert UTC to central daylight time, subtract five (5) hours.


October 1999

S M T W R F S
  1 2 3 4 5 6
7 8 9 10 11 12 13
14 15 16 17 18 19 20
21 22 23 24 25 26 27
28 29 30 31      




Related publications:


Link to:

HRDL Lidar
CASES-99 Home Page
CASES-99 Field Catalog
CASES-99 Project Abstract
CIRA Home Page
Center for Geosciences/Atmospheric Research (CG/AR)
Last updated: April 5, 2002

Comments? Questions? Suggestions? E-mail at (Yelena.Pichugina@noaa.gov).