Temperatures in Victoria

The size of the 2007 anom­aly prompts the ques­tion: ‘what (on earth) was going on in Vic­to­ria in 2007?’. The sec­ond chart (over the fold) shows some ‘out­liers’ that may account for the high mean in 2007. The ‘May’ out­lier is from that year. The out­liers in June (win­ter in Vic­to­ria) are from 1991 and 1957, while the July out­lier is from 1975. All were oth­er­wise rather cool years.click for larger image

R coode for the time-series plot

# Go to http://www.bom.gov.au/cgi-bin/silo/cli_var/area_timeseries.pl
# Using the instructions there, define a grid covering Victoria
# (Hint: start by clicking at Lat:142E and subsequently at Long:40S)
# Generate the time series and copy the table to a text editor
# (unfortunately this data set does not seem to be available via ftp)
# Save the table to a text file and move to R
# Read the text file ('file')
# file<-"/bom_data.txt"
# Table 'f' should have 14 Vectors of monthly mean anomalies and an annual anomaly mean
f<-read.table(file,skip=9,fill=FALSE, row.names=1, col.names=c("Year","Jan","Feb","Mar","Apr","May","Jun","Jul","Aug","Sep","Oct","Nov","Dec","Annual"))
# Create a time-series of the annual mean anomaly. Don't include the last (incomplete) 2008 series
anomalies<-ts(f["Annual"],start=c(1950,1), end=c(2007,1))
# plot them using a 'stair step' plot
plot(anomalies, type="S", col="darkorange", lwd=2, xlab="", ylab="degrees c", main="Mean Temp Anomalies (Victoria)", sub="Source:BOM, Grid=142.50: 150.50E, 35.50: 39.50S", cex.sub=0.8, font.sub=3, cex.axis=0.8)
# add a center-line for ease of reference
abline(h=0.0, lty=3, col="darkseagreen", lwd=2)
# add some tick marks -- assumes Hmisc library is loaded

R code for the box-plot (using the same data set)

boxplot(f[1:12], col="darkorange", pch=16, notch=TRUE, boxwex=0.6, cex.axis=0.8, ylab="anomaly, degrees c", main="Mean, quartiles and outliers of monthly records (1950-2007)")

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