soil: Soil heating

In pzylstra/frame_r: Fire Research and Modelling Environment

Soil heating

Description

Calculates the dynamic heating of a soil at 1cm increments, to 5cm depth

Usage

soil(
  Surf,
  Plant,
  step = 0.01,
  diameter = 6,
  surface = 677,
  RH = 0.2,
  moisture = 0.1,
  distance = 50,
  trail = 600,
  var = 10,
  Pressure = 1013.25,
  Altitude = 0,
  texture = "sand",
  peat = 0,
  grain = "fine",
  unfrozen = 1,
  startTemp = 25,
  updateProgress = NULL
)

Arguments

Surf	The dataframe 'runs' exported from Monte Carlos as 'Summary.csv'
Plant	The dataframe 'IP' exported from Monte Carlos as 'IP.csv'.
step	The increment of soil depth at which each calculation will be modelled (m)
diameter	Diameter of the surface fuels burning (mm)
surface	Temperature at the surface of the soil, under burning fuels
RH	The relative humidity (0-1)
moisture	The proportion oven-dry weight of moisture in the bark and wood
distance	The furthest horizontal distance between the flame origin and the point (m)
trail	Number of seconds to continue modelling after the front has passed
var	The angle in degrees that the plume spreads above/below a central vector;defaults to 10
Pressure	Sea level atmospheric pressure (hPa)
Altitude	Height above sea level (m)
texture	Soil texture. Allowable values are: "sand", "loamy sand", "sandy loam", "sandy clay loam", "sand clay", "loam", "clay loam", "silt loam", "clay", "silty clay", "silty clay loam", "silt"
peat	Organic proportion of the soil
grain	Allowable values are "fine" or "coarse"
unfrozen	Proportion of soil unfrozen, between 0 and 1
updateProgress	Progress bar for use in the dashboard
soilTemp	The starting temperature under the ground (deg C)

Details

Assumes all to be A horizon, with constant, uncompacted density

Utilises the output tables from 'threat' and adds to these the Reynolds Number, heat transfer coefficients, Newton's convective energy transfer coefficient, and the temperature of the object each second.

Reynolds Number utilises a standard formulation (e.g. Gordon, N. T., McMahon, T. A. & Finlayson, B. L. Stream hydrology: an introduction for ecologists. (Wiley, 1992))

Convective heat transfer coefficients use the widely adopted formulations of Williams, F. A. Urban and wildland fire phenomenology. Prog. Energy Combust. Sci. 8, 317–354 (1982), and Drysdale, D. An introduction to fire dynamics. (John Wiley and Sons, 1985) utilising a Prandtl number of 0.7.

Heat is transferred into the earth using Fourier's Law. Spread continues for a period after the passage of the fire front, equal to the duration of the surface flame, as determined using Burrows, N. D. Flame residence times and rates of weight loss of eucalypt forest fuel particles. Int. J. Wildl. Fire 10, 137–143 (2001).

Default temperature of the resident flame is the average of the surface maximums in Cawson, J. G., Nyman, P., Smith, H. G., Lane, P. N. J. & Sheridan, G. J. How soil temperatures during prescribed burning affect soil water repellency, infiltration and erosion. Geoderma 278, 12–22 (2016).

Heating area is set to 1m2, flat, with a characteristic length of 1m

Broad germination and seed death temperatures are based on Auld, T. D. & O’Connel, M. A. Predicting patterns of post‐fire germination in 35 eastern Australian Fabaceae. Aust. J. Ecol. 16, 53–70 (1991).

Predicts death of fine roots at 60C, but does not yet include a time component.

Value

dataframe

pzylstra/frame_r documentation built on Nov. 12, 2023, 1:55 a.m.