• Baldocchi, D. D., and B. A. Hutchison, 1987: Turbulence in an almond orchard: Vertical variation in turbulent statistics. Bound.-Layer Meteor., 40, 127146, https://doi.org/10.1007/BF00140072.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Baldocchi, D. D., and T. P. Meyers, 1988: Turbulence structure in a deciduous forest. Bound.-Layer Meteor., 43, 345364, https://doi.org/10.1007/BF00121712.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Banerjee, T., F. De Roo, and M. Mauder, 2017: Connecting the failure of K theory inside and above vegetation canopies and ejection–sweep cycles by a large-eddy simulation. J. Appl. Meteor. Climatol., 56, 31193131, https://doi.org/10.1175/JAMC-D-16-0363.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Beer, T., 1991: The interaction of wind and fire. Bound.-Layer Meteor., 54, 287308, https://doi.org/10.1007/BF00183958.

  • Bergström, H., and U. Högström, 1989: Turbulent exchange above a pine forest II: Organized structures. Bound.-Layer Meteor., 49, 231263, https://doi.org/10.1007/BF00120972.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Charney, J. J., and Coauthors, 2019: Assessing forest canopy impacts on smoke concentrations using a coupled numerical model. Atmosphere, 10, 273, https://doi.org/10.3390/atmos10050273.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Chen, F., 1990: Turbulent characteristics over a rough natural surface. Part I: Turbulent structures. Bound.-Layer Meteor., 52, 151175, https://doi.org/10.1007/BF00123182.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Clements, C. B., 2007: Experimental studies of fire-atmosphere interactions during grass fires. Ph.D. dissertation, University of Houston, 142 pp.

  • Clements, C. B., and Coauthors, 2007: Observing the dynamics of wildland grass fires. Bull. Amer. Meteor. Soc., 88, 13691382, https://doi.org/10.1175/BAMS-88-9-1369.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Clements, C. B., S. Zhong, X. Bian, W. E. Heilman, and D. W. Byun, 2008: First observations of turbulence generated by grass fires. J. Geophys. Res., 113, D22102, https://doi.org/10.1029/2008JD010014.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Coen, J. L., M. Cameron, J. Michalakes, E. G. Patton, P. J. Riggan, and K. M. Yedinak, 2013: WRF-Fire: Coupled weather–wildland fire modeling with the Weather Research and Forecasting model. J. Appl. Meteor. Climatol., 52, 1638, https://doi.org/10.1175/JAMC-D-12-023.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Cunningham, P., and R. R. Linn, 2007: Numerical simulations of grass fires using a coupled atmosphere-fire model: Dynamics of fire spread. J. Geophys. Res., 112, D05108, https://doi.org/10.1029/2006JD007638.

    • Search Google Scholar
    • Export Citation
  • Finnigan, J. J., 1979: Turbulence in waving wheat. Part II. Structure of momentum transfer. Bound.-Layer Meteor., 16, 213236, https://doi.org/10.1007/BF02350512.

    • Search Google Scholar
    • Export Citation
  • Finnigan, J. J., 2000: Turbulence in plant canopies. Annu. Rev. Fluid Mech., 32, 519571, https://doi.org/10.1146/annurev.fluid.32.1.519.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Forthofer, J. M., and S. L. Goodrick, 2011: Review of vortices in wildland fire. J. Combust., 2011, 114, https://doi.org/10.1155/2011/984363.

  • Heilman, W. E., S. Zhong, J. L. Hom, and J. J. Charney, 2013: Development of modeling tools for predicting smoke dispersion from low-intensity fires. U.S. Joint Fire Science Program Project 09-1-04-1 Final Rep., 65 pp., https://www.firescience.gov/projects/09-1-04-1/project/09-1-04-1_final_report.pdf.

  • 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. Atmos. Sci. Lett., 16, 453460, https://doi.org/10.1002/asl.581.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Heilman, W. E., X. Bian, K. L. Clark, N. S. Skowronski, J. L. Hom, and M. R. Gallagher, 2017: Atmospheric turbulence observations in the vicinity of surface fires in forested environments. J. Appl. Meteor. Climatol., 56, 31333150, https://doi.org/10.1175/JAMC-D-17-0146.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Heilman, W. E., X. Bian, K. L. Clark, and S. Zhong, 2019: Observations of turbulent heat and momentum fluxes during wildland fires in forested environments. J. Appl. Meteor. Climatol., 58, 813829, https://doi.org/10.1175/JAMC-D-18-0199.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Katul, G., and J. D. Albertson, 1998: An investigation of higher-order closure models for a forested canopy. Bound.-Layer Meteor., 89, 4774, https://doi.org/10.1023/A:1001509106381.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Katul, G., G. Kuhn, J. Schieldge, and C.-I. Hsieh, 1997: The ejection-sweep character of scalar fluxes in the unstable surface layer. Bound.-Layer Meteor., 83 (1), 126, https://doi.org/10.1023/A:1000293516830.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Katul, G., D. Poggi, D. Cava, and J. Finnigan, 2006: The relative importance of ejections and sweeps to momentum transfer in the atmospheric boundary layer. Bound.-Layer Meteor., 120, 367375, https://doi.org/10.1007/s10546-006-9064-6.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Kiefer, M. T., W. E. Heilman, S. Zhong, J. J. Charney, and X. Bian, 2015: Mean and turbulent flow downstream of a low-intensity fire: Influence of canopy and background atmospheric conditions. J. Appl. Meteor. Climatol., 54, 4257, https://doi.org/10.1175/JAMC-D-14-0058.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Linn, R. R., and P. Cunningham, 2005: Numerical simulations of grass fires using a coupled atmosphere–fire model: Basic fire behavior and dependence on wind speed. J. Geophys. Res., 110, D13107, https://doi.org/10.1029/2004JD005597.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Linn, R. R., J. Reisner, J. J. Colman, and J. Winterkamp, 2002: Studying wildfire behavior using FIRETEC. Int. J. Wildland Fire, 11, 233246, https://doi.org/10.1071/WF02007.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Maitani, T., and E. Ohtaki, 1987: Turbulent transport processes of momentum and sensible heat in the surface layer over a paddy field. Bound.-Layer Meteor., 40, 283293, https://doi.org/10.1007/BF00117452.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Maitani, T., and R. H. Shaw, 1990: Joint probability analysis of momentum and heat fluxes at a deciduous forest. Bound.-Layer Meteor., 52, 283300, https://doi.org/10.1007/BF00122091.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Mell, W., M. A. Jenkins, J. Gould, and P. Cheney, 2007: A physics-based approach to modelling grassland fires. Int. J. Wildland Fire, 16 (1), 122, https://doi.org/10.1071/WF06002.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Mell, W., A. Maranghides, R. McDermott, and S. Manzello, 2009: Numerical simulation and experiments of burning Douglas fir trees. Combust. Flame, 156, 20232041, https://doi.org/10.1016/j.combustflame.2009.06.015.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Mueller, E., W. Mell, and A. Simeoni, 2014: Large eddy simulation of forest canopy flow for wildland fire modeling. Can. J. For. Res., 44, 15341544, https://doi.org/10.1139/cjfr-2014-0184.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Pimont, F., J.-L. Dupuy, R. R. Linn, and S. Dupont, 2009: Validation of FIRETEC wind-flows over a canopy and fuel-break. Int. J. Wildland Fire, 18, 775790, https://doi.org/10.1071/WF07130.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Poggi, D., and G. Katul, 2007: The ejection-sweep cycle over bare and forested gentle hills: A laboratory experiment. Bound.-Layer Meteor., 122, 493515, https://doi.org/10.1007/s10546-006-9117-x.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Poggi, D., A. Porporato, L. Ridolfi, J. D. Albertson, and G. G. Katul, 2004: The effect of vegetation density on canopy sub-layer turbulence. Bound.-Layer Meteor., 111, 565587, https://doi.org/10.1023/B:BOUN.0000016576.05621.73.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Raupach, M. R., 1981: Conditional statistics of Reynolds stress in rough-wall and smooth-wall turbulent boundary layers. J. Fluid Mech., 108, 363382, https://doi.org/10.1017/S0022112081002164.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Seto, D., C. B. Clements, and W. E. Heilman, 2013: Turbulence spectra measured during fire front passage. Agric. For. Meteor., 169, 195210, https://doi.org/10.1016/j.agrformet.2012.09.015.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Shaw, R. H., J. Tavangar, and D. P. Ward, 1983: Structure of the Reynolds stress in a canopy layer. J. Climate Appl. Meteor., 22, 19221931, https://doi.org/10.1175/1520-0450(1983)022<1922:SOTRSI>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Skowronski, N. S., K. L. Clark, M. Duveneck, and J. Hom, 2011: Three-dimensional canopy fuel loading predicted using upward and downward sensing LiDAR systems. Remote Sens. Environ., 115, 703714, https://doi.org/10.1016/j.rse.2010.10.012.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Su, H.-B., R. H. Shaw, U. K. T. Paw, C.-H. Moeng, and P. P. Sullivan, 1998: Turbulent statistics of neutrally stratified flow within and above a sparse forest from large-eddy simulation and field observations. Bound.-Layer Meteor., 88, 363397, https://doi.org/10.1023/A:1001108411184.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Sun, R., S. K. Krueger, M. A. Jenkins, M. A. Zulauf, and J. J. Charney, 2009: The importance of fire–atmosphere coupling and boundary-layer turbulence to wildfire spread. Int. J. Wildland Fire, 18, 5060, https://doi.org/10.1071/WF07072.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Thomas, C., and T. Foken, 2007: Flux contribution of coherent structures and its implications for the exchange of energy and matter in a tall spruce canopy. Bound.-Layer Meteor., 123, 317337, https://doi.org/10.1007/s10546-006-9144-7.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wallace, J. M., 2016: Quadrant analysis in turbulence research: History and evolution. Annu. Rev. Fluid Mech., 48, 131158, https://doi.org/10.1146/annurev-fluid-122414-034550.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wallace, J. M., R. S. Brodkey, and H. Eckelmann, 1972: The wall region in turbulent shear flow. J. Fluid Mech., 54, 3948, https://doi.org/10.1017/S0022112072000515.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wilczak, J. M., S. P. Oncley, and S. A. Stage, 2001: Sonic anemometer tilt correction algorithms. Bound.-Layer Meteor., 99, 127150, https://doi.org/10.1023/A:1018966204465.

    • Crossref
    • Search Google Scholar
    • Export Citation
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Observations of Sweep–Ejection Dynamics for Heat and Momentum Fluxes during Wildland Fires in Forested and Grassland Environments

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  • 1 USDA Forest Service Northern Research Station, Lansing, Michigan
  • 2 Department of Civil and Environmental Engineering, University of California, Irvine, Irvine, California
  • 3 Department of Meteorology and Climate Science, San José State University, San Jose, California
  • 4 USDA Forest Service Northern Research Station, New Lisbon, New Jersey
  • 5 Department of Geography, Environment, and Spatial Sciences, Michigan State University, East Lansing, Michigan
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Abstract

The vertical turbulent transfer of heat and momentum in the lower atmospheric boundary layer is accomplished through intermittent sweep, ejection, outward interaction, and inward interaction events associated with turbulent updrafts and downdrafts. These events, collectively referred to as sweep–ejection dynamics, have been studied extensively in forested and nonforested environments and reported in the literature. However, little is known about the sweep–ejection dynamics that occur in response to turbulence regimes induced by wildland fires in forested and nonforested environments. This study attempts to fill some of that knowledge gap through analyses of turbulence data previously collected during three wildland (prescribed) fires that occurred in grassland and forested environments in Texas and New Jersey. Tower-based high-frequency (10 or 20 Hz) three-dimensional wind-velocity and temperature measurements are used to examine frequencies of occurrence of sweep, ejection, outward interaction, and inward interaction events and their actual contributions to the mean vertical turbulent fluxes of heat and momentum before, during, and after the passage of fire fronts. The observational results suggest that wildland fires in these environments can substantially change the sweep–ejection dynamics for turbulent heat and momentum fluxes that typically occur when no fires are present, especially the relative contributions of sweeps versus ejections in determining overall heat and momentum fluxes.

© 2021 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).

Corresponding author: Warren E. Heilman, warren.heilman@usda.gov

Abstract

The vertical turbulent transfer of heat and momentum in the lower atmospheric boundary layer is accomplished through intermittent sweep, ejection, outward interaction, and inward interaction events associated with turbulent updrafts and downdrafts. These events, collectively referred to as sweep–ejection dynamics, have been studied extensively in forested and nonforested environments and reported in the literature. However, little is known about the sweep–ejection dynamics that occur in response to turbulence regimes induced by wildland fires in forested and nonforested environments. This study attempts to fill some of that knowledge gap through analyses of turbulence data previously collected during three wildland (prescribed) fires that occurred in grassland and forested environments in Texas and New Jersey. Tower-based high-frequency (10 or 20 Hz) three-dimensional wind-velocity and temperature measurements are used to examine frequencies of occurrence of sweep, ejection, outward interaction, and inward interaction events and their actual contributions to the mean vertical turbulent fluxes of heat and momentum before, during, and after the passage of fire fronts. The observational results suggest that wildland fires in these environments can substantially change the sweep–ejection dynamics for turbulent heat and momentum fluxes that typically occur when no fires are present, especially the relative contributions of sweeps versus ejections in determining overall heat and momentum fluxes.

© 2021 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).

Corresponding author: Warren E. Heilman, warren.heilman@usda.gov
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