Download and install R.
Tip: Only the base directory is needed.
Click on the icon to start R. With Linux/Unix, type the letter R from a command window.
Read the data into R by typing on the command line:
_StormMax=read.csv - "http://garnet.fsu.edu/jelsner/extspace/extremedatasince1899.csv":http://garnet.fsu.edu/jelsner/extspace/extremedatasince1899.csv
Caution: The quotes must be bidirectional. With a copy/paste directly from this document, the quotes will most likely be unidirectional causing an error message.
Subset the cyclones by basin (cyclones away from the U.S. coastline) and by year after 1977 (satellite era) by typing:
StormMaxBasin=subset(StormMax,Region=="Basin"); StormMaxBasin=subset(StormMaxBasin,Yr>1977)
Make the columns of the data set available by name by typing:
attach(StormMaxBasin)
Create an exploratory plot of the annual lifetime maximum wind speed (intensity) as a function of year by typing:
x=boxplot(Wmax~as.factor(Yr),plot=F)
boxplot(Wmax~as.factor(Yr),ylim=c(35,175),xlab="Year",ylab="Intensity (kt)")
xx=1:29
abline(lm(x$stats[5,]~xx),col="red")
abline(lm(x$stats[4,]~xx),col="blue")
abline(lm(x$stats[3,]~xx),col="green")
- Install and load the quantreg package developed by Roger Koenker2. Then print the reference citation.
install.packages("quantreg")
library(quantreg)
citation("quantreg")
- Summarize the results of a quantile regression at the upper quantiles 0.75, 0.9, and 0.95.
summary(rq(Wmax~Yr,tau=c(0.75,0.9,0.95)),se="iid")
Tip: The standard errors (se= argument) can be estimated using other methods, type: ?summary.rq
- Plot the model results.
model=rq(Wmax~Yr,tau=seq(0.2,0.8,0.1))
plot(summary(model,alpha=.05,se="iid"),parm=2,pch=19,cex=1.2,mar=c(5,5,4,2)+0.1,ylab="Trend (kt/yr)",xlab="Quantile")