bomregions {DAAGxtras}R Documentation

Southern Oscillation Index Data

Description

The Southern Oscillation Index (SOI) is the difference in barometric pressure at sea level between Tahiti and Darwin. Annual SOI, Australian regional rainfall data, and Australian regional temperature data are given for the years 1900-2007. The regional rainfall and temperature data are area-weighted averages for the respective regions.

Usage

bomregions

Format

This data frame contains the following columns:

Year
Year
eastRain
east rain
mdRain
Murray-Darling basin rainfall
northRain
north rain
seRain
southeast rain
southRain
south rain
swRain
southwest rain
eastAVt
east temperature
mdAVt
Murray-Darling basin temperature
northAVt
north temperature
seAVt
southeast temperature
southAVt
south temperature
swAVt
southwest temperature
SOI
Annual average Southern Oscillation Index
sunspot
Annual average sunspot counts
auAVrain
Australian average rainfall, area weighted
auAVt
Australian average temperature, area-weighted mean

Source

Australian Bureau of Meteorology web pages:

http://www.bom.gov.au/climate/change/ http://www.bom.gov.au/climate/current/soihtm1.shtml

Regions are identified on a map that can be found at: http://www.bom.gov.au/silo/products/cli_chg/rain_timeseries.shtml

Sunspot data is from http://sidc.oma.be/sunspot-data/

References

Lavery, B., Joung, G. and Nicholls, N. 1997. An extended high-quality historical rainfall dataset for Australia. Australian Meteorological Magazine, 46, 27-38.

Nicholls, N., Lavery, B., Frederiksen, C. and Drosdowsky, W. 1996. Recent apparent changes in relationships between the El Nino – southern oscillation and Australian rainfall and temperature. Geophysical Research Letters 23: 3357-3360.

Examples

 
plot(ts(bomregions[, c("mdRain","SOI")], start=1900), 
     panel=function(y,...)panel.smooth(bomregions$Year, y,...))
avrain <- bomregions[,"mdRain"]
xbomsoi <- with(bomregions, data.frame(SOI=SOI, cuberootRain=avrain^0.33))
xbomsoi$trendSOI <- lowess(xbomsoi$SOI, f=0.1)$y
xbomsoi$trendRain <- lowess(xbomsoi$cuberootRain, f=0.1)$y
xbomsoi$detrendRain <-
  with(xbomsoi, cuberootRain - trendRain + mean(trendRain))    
xbomsoi$detrendSOI <-
  with(xbomsoi, SOI - trendSOI + mean(trendSOI))
## Plot time series avrain and SOI: ts object xbomsoi
plot(ts(xbomsoi[, c("cuberootRain","SOI")], start=1900), 
     panel=function(y,...)panel.smooth(1900:2007, y,...),
     xlab = "Year", main="", ylim=list(c(250, 800),c(-20,25)))
par(mfrow=c(1,2))
rainpos <- pretty(xbomsoi$cuberootRain^3, 6)
plot(cuberootRain ~ SOI, data = xbomsoi, 
     ylab = "Rainfall (cube root scale)", yaxt="n")
axis(2, at = rainpos^0.33, labels=paste(rainpos))
mtext(side = 3, line = 0.8, "A", adj = -0.025)
with(xbomsoi, lines(lowess(cuberootRain ~ SOI, f=0.75)))
plot(detrendRain ~ detrendSOI, data = xbomsoi,
     xlab="Detrended SOI", ylab = "Detrended rainfall", yaxt="n")
axis(2, at = rainpos^0.33, labels=paste(rainpos)) 
with(xbomsoi, lines(lowess(detrendRain ~ detrendSOI, f=0.75)))
mtext(side = 3, line = 0.8, "B", adj = -0.025)
par(mfrow=c(1,1))

[Package DAAGxtras version 0.7-0 Index]