World Ocean Atlas changes

January 25, 2015
By

(This article was first published on Dan Kelley Blog/R, and kindly contributed to R-bloggers)

Introduction

The ocedata R package has a dataset named levitus, which stores sea-surface temperature and salinity. Today, the development version of ocedata (available at github) was updated from the 2009 version of this atlas to the 2013 version. Differences between the two datasets are illustrated here.

Methods

The code provided below requires that the old dataset be saved into an RDA file. The other trick is that 2009 dataset had longitude running from 0 to 360, whereas the 2013 version has it running from -180 to 180, so the matrices have to be sliced and diced a little bit.

Temperature comparison.

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
library(oce)
load("~/ocedata-levitus-before-20150126.rda")
SST2009 <- levitus$SST
SST2009[1:180,] <- levitus$SST[181:360,]
SST2009[181:360,] <- levitus$SST[1:180,]
data(levitus, package="ocedata")
data(coastlineWorld)

imagep(levitus$longitude, levitus$latitude, levitus$SST, zlab="SST 2013", col=oceColorsJet, asp=1)
lines(coastlineWorld[["longitude"]], coastlineWorld[["latitude"]])

imagep(levitus$longitude, levitus$latitude, levitus$SST-SST2009, zlab="SST 2013-2009", asp=1, breaks=seq(-1,1,0.2))
lines(coastlineWorld[["longitude"]], coastlineWorld[["latitude"]])

par(mar=c(3, 3, 0.5, 1), mgp=c(2, 0.7, 0))
hist(levitus$SST-SST2009, breaks=100, xlim=c(-1.5, 1.5), xlab="Temperature change 2009-2013", main="")

Salinity comparison.

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
library(oce)
load("~/ocedata-levitus-before-20150126.rda")
SSS2009 <- levitus$SSS
SSS2009[1:180,] <- levitus$SSS[181:360,]
SSS2009[181:360,] <- levitus$SSS[1:180,]
data(levitus, package="ocedata")
data(coastlineWorld)

imagep(levitus$longitude, levitus$latitude, levitus$SSS, zlab="SSS 2013", col=oceColorsJet, asp=1)
lines(coastlineWorld[["longitude"]], coastlineWorld[["latitude"]])
dev.off()

imagep(levitus$longitude, levitus$latitude, levitus$SSS-SSS2009, zlab="SSS 2013-2009", asp=1, breaks=seq(-1,1,0.2))
lines(coastlineWorld[["longitude"]], coastlineWorld[["latitude"]])

par(mar=c(3, 3, 0.5, 1), mgp=c(2, 0.7, 0))
hist(levitus$SSS-SSS2009, breaks=100, xlim=c(-1.5, 1.5), xlab="Salinity change 2009-2013", main="")

Results

Temperature comparison.

center
center
center

Salinity comparison.

center
center
center

To leave a comment for the author, please follow the link and comment on their blog: Dan Kelley Blog/R.

R-bloggers.com offers daily e-mail updates about R news and tutorials on topics such as: Data science, Big Data, R jobs, visualization (ggplot2, Boxplots, maps, animation), programming (RStudio, Sweave, LaTeX, SQL, Eclipse, git, hadoop, Web Scraping) statistics (regression, PCA, time series, trading) and more...



If you got this far, why not subscribe for updates from the site? Choose your flavor: e-mail, twitter, RSS, or facebook...

Comments are closed.

Search R-bloggers


Sponsors

Never miss an update!
Subscribe to R-bloggers to receive
e-mails with the latest R posts.
(You will not see this message again.)

Click here to close (This popup will not appear again)