Editorial Type:
Article
Article Type:
Research Article

The Role of Quantitative Infrared Imagery in Investigations of the Nocturnal Boundary Layer

Lawrence F. Radke Atmospheric Technology Division, National Center for Atmospheric Research, Boulder, Colorado

Search for other papers by Lawrence F. Radke in
Current site
Google Scholar
PubMed Close
and
Anthony C. Delany Atmospheric Technology Division, National Center for Atmospheric Research, Boulder, Colorado

Search for other papers by Anthony C. Delany in
Current site
Google Scholar
PubMed Close
Print Publication:
01 Nov 2002
DOI:
https://doi.org/10.1175/1520-0426(2002)019<1783:TROQII>2.0.CO;2
Page(s):
1783–1792
Restricted access

We are aware of a technical issue preventing figures and tables from showing in some newly published articles in the full-text HTML view.
While we are resolving the problem, please use the online PDF version of these articles to view figures and tables.

Abstract

During the Cooperative Atmospheric–Surface Exchange Study in 1999 (CASES99), an intensive investigation of the stable nocturnal boundary layer, a versatile and sensitive cryogenically cooled thermal imaging radiometer, the Inframetrics PM 380 Thermal Camera, was deployed. The 60-m-high instrumented tower at the central CASES99 site provided the perch from which to survey the instrumented research field. The field of view of 16° (0.28 sr) and an angular resolution of 1/16° (0.0011 sr) enabled a segment of landscape 500 m distant, of approximately 150-m width, to be viewed with a resolution of approximately 0.5 m. Or, looking down from the 50-m level of the tower, a section of the ground surface 15 m on a side could be viewed with a resolution of 5 cm. The surface brightness temperature of any area could be surveyed with a temperature resolution of 0.1°C and a time resolution of 30 Hz. The information obtained from analysis of these thermal images uniquely complemented the data acquired by the more conventional radiometric and meteorological instrumentation. The thermal imager provided valuable information on the landscape-scale changes of surface temperature after sunset and yielded insights into the development of surface drainage flow and its initiation. Also during periods of nocturnal stability the movement of thermal features across the standing vegetation could be traced, allowing the propagation of eddies to be investigated. The examination of apparently uniform land surfaces enabled a quantified analysis of the inhomogeneities of longwave emission. This information is critically important for the understanding of errors in the surface energy balance. The nocturnal thermal images of mature deciduous trees illustrated the extent to which trees modulate local airflow patterns. Finally, the tantalizing prospect of utilizing the thermal image of the 60-m tower itself to achieve a surrogate air temperature profile was examined.

Corresponding author address: Dr. Anthony C. Delany, Atmospheric Technology Division, NCAR, P.O. Box 3000, Boulder, CO 80302. Email: delany@ucar.edu

Abstract

During the Cooperative Atmospheric–Surface Exchange Study in 1999 (CASES99), an intensive investigation of the stable nocturnal boundary layer, a versatile and sensitive cryogenically cooled thermal imaging radiometer, the Inframetrics PM 380 Thermal Camera, was deployed. The 60-m-high instrumented tower at the central CASES99 site provided the perch from which to survey the instrumented research field. The field of view of 16° (0.28 sr) and an angular resolution of 1/16° (0.0011 sr) enabled a segment of landscape 500 m distant, of approximately 150-m width, to be viewed with a resolution of approximately 0.5 m. Or, looking down from the 50-m level of the tower, a section of the ground surface 15 m on a side could be viewed with a resolution of 5 cm. The surface brightness temperature of any area could be surveyed with a temperature resolution of 0.1°C and a time resolution of 30 Hz. The information obtained from analysis of these thermal images uniquely complemented the data acquired by the more conventional radiometric and meteorological instrumentation. The thermal imager provided valuable information on the landscape-scale changes of surface temperature after sunset and yielded insights into the development of surface drainage flow and its initiation. Also during periods of nocturnal stability the movement of thermal features across the standing vegetation could be traced, allowing the propagation of eddies to be investigated. The examination of apparently uniform land surfaces enabled a quantified analysis of the inhomogeneities of longwave emission. This information is critically important for the understanding of errors in the surface energy balance. The nocturnal thermal images of mature deciduous trees illustrated the extent to which trees modulate local airflow patterns. Finally, the tantalizing prospect of utilizing the thermal image of the 60-m tower itself to achieve a surrogate air temperature profile was examined.

Corresponding author address: Dr. Anthony C. Delany, Atmospheric Technology Division, NCAR, P.O. Box 3000, Boulder, CO 80302. Email: delany@ucar.edu

Save
Cover Journal of Atmospheric and Oceanic Technology
Journal of Atmospheric and Oceanic Technology

  • Anderson, J. M., and Wilson S. B. , 1984: The physical basis of current infrared remote-sensing techniques and the interpretation of data from aerial surveys. Int. J. Remote Sens., 5 , 1.

    • Crossref
    • Search Google Scholar
    • Export Citation

  • Clark, T. L., Radke L. , Coen J. , and Middleton D. , 1999: Analysis of small-scale convective dynamics in a crown fire using infrared video camera imagery. J. Appl. Meteor., 38 , 1401–1420.

    • Crossref
    • Search Google Scholar
    • Export Citation

  • Delany, A. C., and Semmer S. R. , 1998: An integrated surface radiation measurement system. J. Atmos. Oceanic Technol., 15 , 46–53.

    • Crossref
    • Search Google Scholar
    • Export Citation

  • Finnigan, J. J., 1979: Turbulence in waving wheat. Part 1: Mean statistics and honami. Bound.-Layer Meteor., 16 (2) 181–211.

  • Garratt, J. R., 1992: The Atmospheric Boundary Layer. Cambridge University Press, 316 pp.

  • LeMone, M. A., and Coauthors. 2000: Land–atmosphere interaction research and opportunities in the Walnut River Watershed in Southeast Kansas: CASES and ABLE. Bull. Amer. Meteor. Soc., 81 , 757–780.

    • Crossref
    • Search Google Scholar
    • Export Citation

  • Mahrt, L., Vickers D. , Sun J. , Burns S. , and Lenschow D. , 2001: Shallow drainage flows. Bound.-Layer Meteor.,101, 243–260.

  • Militzer, J. M., Michealis M. C. , Semmer S. R. , Norris K. S. , Horst T. W. , Oncley S. P. , Delany A. C. , and Brock F. M. , 1995: Development of the prototype PAM III/flux–PAM surface meteorological station. Preprints, Ninth Symp. Meteorological Observation and Instrumentation, Charlotte, NC, Amer. Meteor. Soc., 490–494.

    • Search Google Scholar
    • Export Citation

  • Radke, L. F., Clark T. L. , Coen J. L. , Walther C. , Lockwood R. , Riggan P. J. , Brass J. , and Higgins R. , 2000: The WildFire Experiment (WiFE): Observations with Airborne Remote Sensors. Can. J. Remote Sens.,26, 400–417.

    • Search Google Scholar
    • Export Citation

  • Rees, W. G., 1990: Topics in Remote Sensing 1: Physical Principles of Remote Sensing. Cambridge University Press, 247 pp.

  • Scorer, R. S., 1978: Environmental Aerodynamics. Halsted Press, 487 pp.

  • Sun, J., Burns S. P. , Delany A. C. , Horst T. W. , Oncley S. P. , and Lenschow D. H. , 2001: Energy balance in nocturnal boundary layers. Bound.-Layer Meteor., in press.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 286 129 54
PDF Downloads 51 12 0