ffm {firebehavioR}

Estimate fine fuel moisture

Description

Methods to estimate fine fuel moisture based on meteorological data.

Usage

ffm(method, rh, temp, month, hour, asp, slp, bla, shade)

Arguments

method

a character vector of specifying the method ("pech", "simard", "wagner", "anderson", "mcarthur", "fbo")

rh

a numeric vector of relative humidities (%)

temp

a numeric vector of dry bulb temperatures (deg. C)

month

a numeric vector of Gregorian month numbers (1-12)

hour

a numeric vector of hours (1-24)

asp

a character vector of aspects specified as cardinal directions, either "N", "S", "E", or "W"

slp

a numeric vector of topographic slopes (%)

bla

a character vector specifying the difference in elevation between the fine fuel's location and that of the meteorological data; either within 305 m ('l', the default), or the meteorological data are > 305m below ("b"), or above ("a") the fine fuel's location

shade

a character vector specifying whether fine fuels are shaded, "y" or "n"

Details

This function has six methods to estimate fine fuel moisture. If method = "fbo", all arguments must be specified, otherwise, only method, rh and temp are required.

Value

a data frame of litter, 1-hr, 10-hr, and 100-hr fuel moistures

Author(s)

Justin P Ziegler, [e-mail]

References

Viney, N.R. 1991. A review of fine fuel moisture modelling. International Journal of Wildland Fire. 1(4):215–234.

Examples

#Example using RAWS meteorological station data
data(rrRAWS)
wx = rrRAWS[2000:3000,]
ff = rbind(
data.frame(ffm = ffm('simard',wx$rh, wx$temp_c)$fm1hr,method='simard'),
data.frame(ffm = ffm('wagner',wx$rh, wx$temp_c)$fm1hr,method='wagner'),
data.frame(ffm = ffm('anderson',wx$rh, wx$temp_c)$fm1hr,method='anderson')
)
ff$dateTime = rep(wx$dateTime,3)
par(mfrow=c(3,1))
hist(ff$ffm[ff$method=="simard"])
hist(ff$ffm[ff$method=="wagner"])
hist(ff$ffm[ff$method=="anderson"])

#The FBO method requires more inputs
rh = wx$rh
temp =wx$temp_c
month = as.numeric(format(strptime(wx$dateTime,"%m/%d/%Y %H:%M"),'%m'))
hour = as.numeric(format(strptime(wx$dateTime,"%m/%d/%Y %H:%M"),'%H'))
ffm(method = 'fbo', rh, temp, month, hour, asp = 'N', slp = 10, bla = 'l', shade = 'n')