Forest Disturbance Processes

Analyses of Fire-Induced Atmospheric Turbulence Regimes from Field Observations

[image:] Arttwork for the Eastern Area Modeling ConsortiumResearch Issue

Recent field experiments focused on in-situ monitoring of atmospheric turbulent conditions and fire-atmosphere feedbacks during wildland fire events have generated new observational data sets that provide new opportunities for analyzing fire-induced atmospheric turbulence regimes.  These turbulence regimes can play a significant role in the spread of wildland fires and the dispersion of smoke from those fires.  Thus far, monitoring studies and associated data analyses efforts have focused on general characteristics of the turbulent circulations, turbulent kinetic energy (TKE), and turbulent fluxes of heat and momentum that occur before, during, and after fire front passage.  New analyses are needed to further analyze properties of atmospheric turbulence in the vicinity of wildland fires and the mechanisms involved in the generation and dissipation of turbulence with and without the presence of forest overstory vegetation.  It is through these analyses that improved representations (i.e. parameterizations) of atmospheric turbulence effects on fire behavior and smoke dispersion in operational fire behavior and smoke prediction systems may be possible.

Our Research

[photo:] Prescribed grass fire with flux towerTo improve our understanding of atmospheric turbulence regimes that develop in the vicinity of wildland fires and how those regimes can affect fire behavior and smoke transport, Northern Research Station scientists in collaboration with researchers at San Jose State University are analyzing existing data collected during grass fire and sub-canopy fire experiments in order to better characterize atmospheric turbulent circulations during wildland fire events.  The research objectives for this study include

  • Investigating the properties of atmospheric turbulence spectra (and co-spectra) under different fuel, terrain, and forest overstory conditions before, during, and after fire-front passage in relation to various fire intensities and atmospheric conditions using existing and new observational data sets.
  • Determining fire-induced turbulent flow characteristics by analyzing turbulent kinetic energy budgets, turbulence anisotropy, and turbulent length scales derived from existing and new observational data sets.

Expected Outcomes

The analyses carried out in this study will increase our understanding of how wildland fires affect atmospheric turbulent circulations in the vicinity of those fires.  The results may lead to improved parameterizations of fire-atmosphere interactions and improved predictions of fire spread and smoke dispersion in fire-behavior and air-quality modeling systems.  Finally, the analyses and summary report resulting from this study will contribute to the Core Fire-Science Portfolio of the National Wildland Fire and Fuels Research and Development Strategic Plan.

Research Results

Heilman, W. E., C. B. Clements, D. Seto, X. Bian, K. L. Clark, N. S. Skowronski, and J. L. Hom.  2015. Observations of fire-induced turbulence regimes during low-intensity wildland fires in forested environments: Implications for smoke dispersion.  Atmospheric Science Letters 16:453-460.

Clements, C. B., B. Davis, D. Seto, J. Contezac, J.-B. Fillipi, N. Lareau, B. Barboni, B. Butler, S. Krueger, R. Ottmar, R. Vihnanek, W. E. Heilman, J. Flynn, M. A. Jenkins, J. Mandel, C. Teske, D. Jimenez, J. O’Brien, and B. Lefer.  2015.  Overview of the 2013 FireFlux-II grass fire field experiment.  In: D. X. Viegas, Ed., Advances in Forest Fire Research, Coimbra University Press, Coimbra, Portugal.  pp. 392-400.

Heilman, W. E., S. Zhong, J. L. Hom, J. J. Charney, M. T. Kiefer, K. L. Clark, N. Skowronski, G. Bohrer, W. Lu, Y. Liu, R. Kremens, X. Bian, M. Gallagher, M. Patterson, J. Nikolic, T. Chatziefstratiou, C. Stegall, and K. Forbus.  2013.  Development of modeling tools for predicting smoke dispersion from low-intensity fires.  Final Report, U.S. Joint Fire Science Program, Project 09-1-04-1.  [Online]. Available: <http://www.firescience.gov/projects/09-1-04-1/project/09-1-04-1_final_report.pdf>

Charland, A.M.; Clements, C.B.  2013.  Kinematic structure of a wildland fire plume observed by Doppler Lidar.  Journal of Geophysical Research – Atmospheres 118:3200-3212.

Seto, D.; Clements, C.; Heilman, W.E.  2013.  Turbulence spectra measured during fire front passage.  Agricultural and Forest Meteorology 169:195-210.

Seto, D.  2012.  Observations and analysis of fire-atmosphere interactions during fire front passage.  Thesis, Department of Meteorology and Climate Science, San Jose State University. 94 pp.

Research Participants

  • Craig Clements, Department of Meteorology and Climate Science, San Jose State University, San Jose, CA
  • Daisuke Seto, Department of Meteorology and Climate Science, San Jose State University, San Jose, CA
  • Warren E. Heilman, US Forest Service, Northern Research Station, Lansing, MI
  • Xindi Bian, US Forest Service, Northern Research Station, Lansing, MI
Last Modified: February 22, 2016