R: Monthly total precipitation (mm) for August 1997 in the Rocky...

RMprecip {fields} | R Documentation

## Monthly total precipitation (mm) for August 1997 in the Rocky Mountain Region and some gridded 4km elevation data sets (m).

### Description

`RMprecip` is a useful spatial data set of moderate size consisting of 806 locations. See www.image.ucar.edu/Data for the source of these data. `PRISMelevation` and `RMelevation` are gridded elevations for the continental US and Rocky Mountain region at 4km resolution. Note that the gridded elevations from the PRISM data product are different than the exact station elevations. (See example below.)

### Format

The data set `RMprecip` is a list containing the following components:

x

  Longitude-latitude position of monitoring stations. Rows names are station id codes consistent with the US Cooperative observer network. The ranges for these coordinates are [-111, -99] for longitude and [35,45] for latitude.

elev

  Station elevation in meters.

y

  Monthly total precipitation in millimeters. for August, 1997

The data sets `PRISMelevation` and `RMelevation` are lists in the usual R grid format for images and contouring

They have the following components:

x

  Longitude grid at approximately 4km resolution

y

  Latitude grid at approximately 4km resolution

z

  Average elevation for grid cell in meters

These elevations and the companion grid formed the basis for the 103-Year High-Resolution Precipitation Climate Data Set for the Conterminous United States ( see http://www.prism.oregonstate.edu/documents/PRISM_downloads_FTP.pdf and also archived at the National Climate Data Center. This work isy authored by Chris Daly www.prism.oregonstate.edu and his PRISM group but had some contribution from the Geophysical Statistics Project at NCAR and is an interpolation of the observational data to a 4km grid that takes into account topography such as elevation and aspect.

### Details

The binary file `RData.USmonthlyMet.bin` can be downwloaded from http://www.image.ucar.edu/Data/US.monthly.met and also includes information on its source.

    # explicit source code to create the RMprecip data
    dir <- "" # include path to data file
    load(paste(dir, "RData.USmonthlyMet.bin", sep="/")
    #year.id<-  1963- 1895
    year.id<- 103
    #pptAUG63<- USppt[ year.id,8,]
    loc<- cbind(USpinfo$lon, USpinfo$lat)
    xr<- c(-111, -99)
    yr<- c( 35, 45)
    station.subset<-  (loc[,1]>= xr[1]) & (loc[,1] <= xr[2]) & (loc[,2]>= yr[1]) & (loc[,2]<= yr[2])
    ydata<-  USppt[ year.id,8,station.subset]
    ydata <- ydata*10 #  cm -> mm conversion
    xdata<- loc[station.subset,]
    dimnames(xdata)<- list( USpinfo$station.id[station.subset], c( "lon", "lat"))
    xdata<- data.frame( xdata)
    good<- !is.na(ydata)
    ydata<- ydata[good]
    xdata<- xdata[good,]

    test.for.zero.flag<- 1
    test.for.zero( unlist(RMprecip$x), unlist(xdata), tag="locations")
    test.for.zero( ydata, RMprecip$y, "values")

### Examples

    # this data set was created  the
    # historical data  taken from
    # Observed monthly precipitation, min and max temperatures for the coterminous US
    # 1895-1997
    # NCAR_pinfill
    # see the Geophysical Statistics Project datasets page for the supporting functions
    # and details.

    # plot
    quilt.plot(RMprecip$x, RMprecip$y)
    US( add=TRUE, col=2, lty=2)

    # comparison of station elevations with PRISM gridded values

    data(RMelevation)

    interp.surface( RMelevation, RMprecip$x)-> test.elev

    plot( RMprecip$elev, test.elev, xlab="Station elevation",
    ylab="Interpolation from PRISM grid")
    abline( 0,1,col="blue")

    # some differences  with high elevations probably due to complex
    # topography!

    #
    # view of Rockies looking from theSoutheast

    save.par<- par(no.readonly=TRUE)

    par( mar=c(0,0,0,0))

    # fancy use of persp with shading and lighting.
    persp( RMelevation, theta=75, phi= 15,
              box=FALSE, axes=FALSE, xlab="", ylab="",
             border=NA,
             shade=.95, lphi= 10, ltheta=80,
             col= "wheat4",
             scale=FALSE, expand=.00025)

    # reset graphics parameters and a more conventional image plot.
    par( save.par)
    image.plot(RMelevation, col=topo.colors(256))
    US( add=TRUE, col="grey", lwd=2)
    title("PRISM elevations (m)")

[Package fields version 9.6.1 Index]