Quick plot of the hadcrut data.

HADCRUTMEDIAN.R

# Download median of regional timeseries
temp <- readLines("https://www.metoffice.gov.uk/hadobs/hadcrut4/data/current/time_series/HadCRUT.4.6.0.0.monthly_ns_avg.txt")
temp <- data.frame(do.call(rbind, strsplit(temp,"   ")),
                      stringsAsFactors = FALSE)
temp[-1] <- lapply(temp[-1], as.numeric)

temp$year <- as.numeric(gsub("/.*","",temp[,1]))
temp$month <- as.numeric(gsub(".*/","",temp[,1]))
temp$time <- temp$year + temp$month/12.5

# Create plot ensemble median
id <- temp$year > 1997
plot(temp$time[id],temp[id,2] + 14, type = "l",
     xlab = "time",
     ylab = "Median of 100 simulations",
     main = "SST bias adjustment simulations of HadCRUT")

# Information on methodology :
# https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2011JD017187
# also explained here with the data format
# https://www.metoffice.gov.uk/hadobs/hadcrut4/data/current/series_format.html