Atmospheric Boundary Layer Experiments (ABLE)

The Atmospheric Boundary Layer Experiments (ABLE) (http://www.atmos.anl.gov/ABLE/) facility was established in 1997 within the Walnut River Watershed in south-central Kansas (USA), east of the city of Wichita, to support studies in boundary layer meteorology, hydrology, ecology, and atmospheric chemistry. ABLE was developed by the Atmospheric Section of the U.S. Department of Energy (DOE), Argonne National Laboratory. The ABLE facility is located within the existing boundaries of DOE's Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) Clouds and Radiation Testbed (CART) and consists of 5 instrumented sites: Augusta (Central Site), Beaumont, Oxford, Smileyberg, and Whitewater.

ABLE was initially designed primarily for investigations of and within the planetary boundary layer (PBL) (the lower part of the troposphere) where the influence of the surface is felt directly through turbulent transport. Topics of interest include the dynamics of the mixed layer during both day and night; effects of varying land use and land form; the interactive roles of precipitation, runoff, and soil moisture; storm development; and energy budgets on scales of 1•100 km. ABLE was designed to augment insufficiently comprehensive PBL data sets— in a variety of synoptic conditions — and support testing of parameterization schemes representing PBL and surface processes in weather and climate models. Existing uncertainty includes whether the wind profiles produced by PBL models are realistic (LeMone et al. 2000; Coulter et al. 1998; Wesely et al. 1997).

The current emphasis (since 2000) of ABLE is evaluation of the carbon cycle at the surface. ABLE is participating in studies of the net air-surface exchange of carbon dioxide in support of AmeriFlux studies of the terrestrial carbon balance. The objectives of the measurement program are to quantify seasonal variations in carbon dioxide and water vapor fluxes, determine vegetative and climatic effects on the carbon dioxide budget, and investigate the carbon balance (through both measurements and modeling). (The AmeriFlux program is designed to provide long-term measurements of carbon dioxide, energy, and water vapor fluxes between terrestrial ecosystems and the atmosphere. See Metadata for Ameriflux registered in ORNL DAAC Mercury or visit the Ameriflux web site at http://public.ornl.gov/ameriflux/Participants/Sites/Map/index.cfm for more information.)

Since 2001, ABLE (DOE Argonne) has also been participating in the DOE Water Cycle Pilot Study (WCPS), along with DOE Lawrence Berkley, Oak Ridge, Brookhaven, and Los Alamos National Laboratories (Miller et al. 2003). The pilot study has produced an extensive database and evaluations of numerical predictions of components of the water budget for three nested domains, two of them within the ABLE area. Data assimilated include field results from a three-month intensive observing period within the ABLE area. The WCPS has also measured changes in leaf area index (LAI) for several vegetation types and groundwater variations at three wells. The study included water isotope sampling in rainwater, streams, soil moisture, lakes, and wells as a means of tracing sources and sinks within and outside the ABLE area.

During 1997 and 1999 ABLE hosted two field campaigns in connection with the Cooperative Atmosphere-Surface Exchange Study (CASES) and provided supplementary measurements and facilities for these shorter-term instrument deployments. CASES is a grassroots, multidisciplinary effort to study the interaction of the lower atmosphere with the land surface, the subsurface, and vegetation over time scales ranging from seconds to years. CASES-97, the first episodic field effort, was held during April•June 1997. CASES-97 studied the role of surface processes in the diurnal variation of the boundary layer, tested radar-based precipitation algorithms, and attempted to define relevant scaling for precipitation and soil properties (LeMone et al. 2000). A second, very successful field program (CASES-99) was conducted within the ABLE array during October 1999 to study the nocturnal boundary layer and the morning and evening boundary layer transitions (Poulos et al. 2002). (See Metadata for CASES registered in ORNL DAAC Mercury.)

The equipment which is available at the ABLE includes:

Three (3) Radar Wind Profilers with Radio Acoustic Sounding Systems (RASS) [measures wind profiles from (nominally) .1 km to 5 km and virtual temperature profiles from .1 km to 2.5 km.];

Three (3) Dopplar Acoustic Sounders (Minisodars) (measures wind profiles from about 10 m to 200 m above the surface, thus filling in the gap left below the minimum height of the wind profilers.);

Five (5) Automated Weather Stations (AWS Systems) (instrumented 10-m towers continuously measure wind direction, wind speed, temperature, humidity, precipitation, and barometric pressure, the latter only at surface characterization sites and the Central Site);

Two (2) Eddy-correlation Flux Measurement Systems (ECOR Stations) (measures surface fluxes of sensible heat, latent heat, momentum, and carbon dioxide);

One (1) Energy Balance Bowen Ratio Systems (EBBR Stations) (measures surface fluxes of sensible and latent heat); and

A network of twenty-eight (28) recording rain gauges.

Atmospheric radiation and soil temperature, moisture, and heat flow are measured continuously at 2 locations. Canopy reflectance and leaf area index are made approximately every two weeks during the growing season at 3 sites. Continuously collected data are available at the ABLE web site in near real-time and archived form (Klazura et al., 2003).

References:

Coulter, R.L., G.E. Klazura, B.M. Lesht, J.D. Shannon, D.L. Sisterson, and M.L Wesely. 1998. Using the ABLE facility to observe urbanization effects on planetary boundary layer processes, Preprints, 10th Joint Conference on the Applications of Air Pollution Meteorology, Phoenix, AZ, Air and Waste Management Assn. and Amer. Meteorol. Soc., pp. J76-J79.

Klazura, G.E., D.R. Cook, R.L. Coulter, R.L. Hart, D.J. Holdridge, B.M. Lesht, J.D. Lucas, T.J. Martin, M.S. Pekour, and M.L. Wesely. 2003. Atmospheric Boundary Layer Measurements in South-Central Kansas. Presented at the 30th International Symposium on Remote Sensing of Environment, 10-14 November 2003, Honolulu, Hawai'i.

LeMone, M.A., R.L. Grossman, R.L. Coulter, M.L. Wesely, G.E. Klazura, G.S. Poulos, W. Blumen, J.K. Lundquist, R.H. Cuenca, S.F. Kelly, E.A. Brandes, S.P. Oncley, R.T. McMillen, and B.B. Hicks. 2000. Land-atmosphere interaction research, early results, and opportunities in the Walnut River Watershed in southeast Kansas: CASES and ABLE, Bull. Amer. Meteorol. Soc., vol 81, pp. 757-779.

Miller, N.L., A.W. King, M.A. Miller, E.P. Springer, M.L. Wesely, K.E. Bashford, M.E. Conrad, K. Costigan, R.L. Coulter, P.N. Foster, H.K. Gibbs, J. Jin, G.E. Klazura, B.M. Lesht, M.V. Machavaram, F. Pan, J. Song, J. Stalker, D. Troyan, R.A. Washington-Allen. 2003. The DOE Water Cycle Pilot Study, Submitted to Bull. Amer. Meteorol. Soc.

Poulos, G.S., W. Blumen, D.C. Fritts, J.K. Lundquist, J. Sun, S.P. Burns, C. Nappo, R. Banta, R. Newsom, J. Cuxart, E. Terradellas, B. Balsley, and M. Jensen, 2002: CASES-99: A comprehensive investigation of the stable nocturnal boundary layer, Bull. Amer. Meteorol. Soc., vol 83, pp. 555-581.

Wesely, M.L., R.L. Coulter, G.E. Klazura, B.M. Lesht, D.L. Sisterson, and J.D. Shannon. 1997. A planetary boundary layer observational capability in Kansas, Preprints, First Symposium on Integrated Observing Systems, Long Beach, CA, Amer. Meteorol. Soc., pp. 169-171.