minnesota.barley.weather {agridat} | R Documentation

## 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.

### Source

National Climate Data Center, http://www.ncdc.noaa.gov/.

### References

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

### Examples

    data(minnesota.barley.yield)
    dat <- minnesota.barley.yield
    data( minnesota.barley.weather)
    datw <- minnesota.barley.weather

    # Weather trends over time
    if(require(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
    if(require(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)
    oldpar <- tpg <- trellis.par.get()
    tpg$superpose.symbol$pch <- substring(levels(mecy$yr),4) # Last digit of year
    trellis.par.set(tpg)
    foo <- xyplot(y~x|covar*site, data=mecy, groups=yr, cex=1, ylim=c(5,65),
                  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")))
    if(require(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
    }
    } # reshape2

[Package agridat version 1.16 Index]