EGU2020-5934
https://doi.org/10.5194/egusphere-egu2020-5934
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Role of horizontal eddy diffusivity within the canopy on fire spread

Yana Bebieva and Kevin Speer
Yana Bebieva and Kevin Speer
  • Florida State University, Geophysical Fluid Dynamics Institute, United States of America (ybebieva@fsu.edu)

Wind profile observations are used to estimate turbulent properties in the atmospheric boundary layer from 1 m up to 300 m height above north Florida pine woods. Basic turbulence characteristics of the lower boundary layer are presented. Together with theoretical models for the mean horizontal velocity we derive the lateral diffusivity using Taylor's frozen turbulence hypothesis in the surface fuel layer (tens of centimeters). This parameter is used to predict the spread of surface fires in a simple 1D model. Initial assessments of sensitivity of the fire spread rates to the lateral diffusivity are made. Estimated lateral diffusivity with and without fire are made and associated fire spread rates are explored. Our results support the conceptual framework that eddy dynamics in the fuel layer is set by larger eddies developed in the canopy layer aloft. The presence of fire modifies the eddy structure depending on the fire intensity.

How to cite: Bebieva, Y. and Speer, K.: Role of horizontal eddy diffusivity within the canopy on fire spread, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-5934, https://doi.org/10.5194/egusphere-egu2020-5934, 2020

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