The Keeling Curve

For the purpose of demonstration we load the Keeling Curve data. Revisit the section on Data sets used to remind yourself how to download and extract the data of interest.

library(xts)
load(url("https://userpage.fu-berlin.de/soga/data/r-data/KeelingCurve.Rdata"))

The data set (co2) shows carbon dioxide (CO₂) measurements taken at the Mauna Loa Observatory in Hawaii. The data is provided by Dr. Pieter Tans, NOAA/ESRL and Dr. Ralph Keeling, Scripps Institution of Oceanography.

Let us get aware of the location by plotting the Mauna Loa Observatory on an interactive map (you may click on the blue dot).

library(sf)
library(mapview)
pnt <- data.frame(x = 204.4239, y = 19.53611)
pnt <- st_as_sf(pnt, coords = c("x", "y"), crs = 4326)

mapview(pnt, map.types = "Esri.WorldImagery")

Let us now plot the actual time series data.

plot(co2, main = "Keeling Curve", ylab = expression("CO"[2] * " (ppm)")
)

The measurements indicate a strong positive trend over time. In addition a strong seasonal pattern is observed, which is related to the seasonal expansion of the terrestrial vegetation of the Northern Hemisphere. During its productive growing phase the vegetation removes CO₂ from the atmosphere, while it returns CO₂ to the air when it dies and decomposes.

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Citation

The E-Learning project SOGA-R was developed at the Department of Earth Sciences by Kai Hartmann, Joachim Krois and Annette Rudolph. You can reach us via mail by soga[at]zedat.fu-berlin.de.

You may use this project freely under the Creative Commons Attribution-ShareAlike 4.0 International License.

Please cite as follow: Hartmann, K., Krois, J., Rudolph, A. (2023): Statistics and Geodata Analysis using R (SOGA-R). Department of Earth Sciences, Freie Universitaet Berlin.