agridat (version 1.23)

minnesota.barley.weather: Monthly weather at 6 sites in Minnesota 1927-1936.

Description

This is monthly weather summaries for the 6 sites where barley yield trials were conducted.

Format

A data frame with 719 observations on the following 8 variables.

site

site, 6 levels

year

year, 1927-1936

mo

month, 1-12, numeric

cdd

monthly cooling degree days, Fahrenheit

hdd

monthly heating degree days, Fahrenheit

precip

monthly precipitation, inches

min

monthly average daily minimum temp, Fahrenheit

max

monthly average daily maximum temp, Fahrenheit

Details

When the weather data was extracted from the National Climate Data Center, the following weather stations were chosen, based on availability of weather data in the given time frame (1927-1936) and the proximity to the town (site) for the barley data.

site	station name	station
Morris	MORRIS WC EXPERIMENTAL STATION	USC00215638
StPaul	MINNEAPOLIS WEATHER BUREAU DOWNTOWN	USC00215433
Crookston	CROOKSTON NW EXPERIMENTAL STATION	USC00211891
GrandRapids	GRAND RAPIDS FRS LAB	USC00213303
Waseca	WASECA EXPERIMENTAL STATION	USC00218692
Duluth	SUPERIOR	USC00478349

'cdd' are cooling degree days, which is the number of degree days with a temperature _above_ 65 Fahrenheit.

'hdd' are heating degree days, _below_ 65 Fahrenheit.

No data is available for Duluth in Dec, 1931.

References

Kevin Wright. 2013. Revisiting Immer's Barley Data. The American Statistitician, 67, 129-133. https://doi.org/10.1080/00031305.2013.801783

Examples

if (FALSE) {
  
library(agridat)
data(minnesota.barley.yield)
dat <- minnesota.barley.yield
data( minnesota.barley.weather)
datw <- minnesota.barley.weather

  # Weather trends over time
  libs(latticeExtra)
  useOuterStrips(xyplot(cdd~mo|year*site, datw, groups=year,
                        main="minnesota.barley",
                        xlab="month", ylab="Cooling degree days",
                        subset=(mo > 3 & mo < 10),
                        scales=list(alternating=FALSE),
                        type='l', auto.key=list(columns=5)))


# Total cooling/heating/precip in Apr-Aug for each site/yr
ww <- subset(datw, mo>=4 & mo<=8)
ww <- aggregate(cbind(cdd,hdd,precip)~site+year, data=ww, sum)

# Average yield per each site/env
yy <- aggregate(yield~site+year, dat, mean)

minn <- merge(ww, yy)


# Higher yields generally associated with cooler temps, more precip
libs(reshape2)
me <- melt(minn, id.var=c('site','year'))
mey <- subset(me, variable=="yield")
mey <- mey[,c('site','year','value')]
names(mey) <- c('site','year','y')
mec <- subset(me, variable!="yield")
names(mec) <- c('site','year','covar','x')
mecy <- merge(mec, mey)
mecy$yr <- factor(mecy$year)
foo <- xyplot(y~x|covar*site, data=mecy, groups=yr, cex=1, ylim=c(5,65),
              par.settings=list(superpose.symbol=list(pch=substring(levels(mecy$yr),4))),
              xlab="", ylab="yield", main="minnesota.barley",
              panel=function(x,y,...) {
                panel.lmline(x,y,..., col="gray")
                panel.superpose(x,y,...)
              },
              scales=list(x=list(relation="free")))
  libs(latticeExtra)
  foo <- useOuterStrips(foo, strip.left = strip.custom(par.strip.text=list(cex=.7)))
  combineLimits(foo, margin.x=2L) # Use a common x axis for all rows

}