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cffdrs (version 1.7.3)

fireSeason: Fire Season Start and End

Description

fireSeason calculates the start and end fire season dates for a given weather station. The current method used in the function is based on three consecutive daily maximum temperature thresholds (Wotton and Flannigan 1993, Lawson and Armitage 2008). This function process input from a single weather station.

Usage

fireSeason(input,fs.start=12,fs.end=5,method="WF93")

Arguments

input
A data.frame containing input variables of including the date/time and daily maximum temperature. Variable names have to be the same as in the following list, but they are case insensitive. The order in which the input variables are entered is not important either.
yr (required)
Year of the observations mon
(required) Month of the observations
day (required)
Day of the observations tmax
(required) Maximum Daily Temperature (degrees C)
fs.start
Temperature threshold (degrees C) to start the fire season (default=12)
fs.end
Temperature threshold (degrees C) to end the fire season (default=5)
method
Method of fire season calculation. Current option is "WF93". Additional methods will be added

Value

fireSeason returns a data frame of season and start and end dates. Columns in data frame are described below.Primary FBP output includes the following 8 variables:
yr
Year of the fire season start/end date
mon
Month of the fire season start/end date
day
Day of the fire season start/end date
fsdatetype
Fire season date type (values are either "start" or "end")

Details

An important aspect to consider when calculating Fire Weather Index (FWI) System variables is a definition of the fire season start and end dates (Lawson and Armitage 2008). If a user starts calculations on a fire season too late in the year, the FWI System variables may take too long to reach equilibrium, thus throwing off the resulting indices. This function presents one method of calculating these start and end dates, adapted from Wotton and Flannigan (1993). The approach taken in this function starts the fire season after three days of maximum temperature greater than 12 degrees Celsius. The end of the fire season is determined after three consecutive days of maximum temperature less than 5 degrees Celsius. The two temperature thresholds can be adjusted as parameters in the function call.

This fire season length definition can also feed in to the overwinter DC calculations (wDC). View the cffdrs package help files for an example of using the fireSeason, wDC, and fwi functions in conjunction.

References

Wotton, B.M. and Flannigan, M.D. (1993). Length of the fire season in a changing climate. Forestry Chronicle, 69, 187-192. http://www.ualberta.ca/~flanniga/publications/1993_Wotton_Flannigan.pdf

Lawson, B.D. and O.B. Armitage. 2008. Weather guide for the Canadian Forest Fire Danger Rating System. Nat. Resour. Can., Can. For. Serv., North. For. Cent., Edmonton, AB http://cfs.nrcan.gc.ca/pubwarehouse/pdfs/29152.pdf

See Also

fwi, wDC

Examples

Run this code
library(cffdrs)
#The standard test data:
data("test_wDC")
print(head(test_wDC))
## Sort the data:
input <- with(test_wDC, test_wDC[order(id,yr,mon,day),])

#Using the default fire season start and end temperature 
#thresholds:
a_fs <- fireSeason(input[input$id==1,])

#Check the result:
a_fs

#    yr mon day fsdatetype
#1 1999   5   4      start
#2 1999   5  12        end
#3 1999   5  18      start
#4 1999   5  25        end
#5 1999   5  30      start
#6 1999  10   6        end
#7 2000   6  27      start
#8 2000  10   7        end

#In the resulting data frame, the fire season starts 
#and ends multiple times in the first year. It is up to the user #for how to interpret this.

#modified fire season start and end temperature thresholds
a_fs <- fireSeason (input[input$id==1,],fs.start=10, fs.end=3)
a_fs
#    yr mon day fsdatetype
#1 1999   5   2      start
#2 1999  10  20        end
#3 2000   6  16      start
#4 2000  10   7        end
#select another id value, specify method explicitly
b_fs <- fireSeason(input[input$id==2,],method="WF93")
#print the calculated fireseason
b_fs
#   yr mon day fsdatetype
#1 1980   4  21      start
#2 1980   9  19        end
#3 1980  10   6      start
#4 1980  10  16        end
#5 1981   5  21      start
#6 1981  10  13        end

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