Plotting monthly global temperatures from UAH dataset

UAHtemps.R

# Plot UAH monthly temperatures
# Joris Meys
# Date last modified: 2019-11-18

# Create a temporary filename
fname <- tempfile()

# Download data into the temporary file
download.file("https://www.nsstc.uah.edu/data/msu/v6.0/tlt/uahncdc_lt_6.0.txt",destfile = fname)

# read in the data
x <- read.table(fname, header = TRUE,
                nrows = 491)
# Remove temporary file
unlink(fname)

# Create a date variable representing the middle of the month
x$time <- as.Date(sprintf("%d-%02d-15", x$Year, x$Mo), 
                  format = "%Y-%m-%d")

# Make month labels
x$month <- factor(x$Mo,
                  labels = month.abb)

# Create the plot
ggplot(tmp,aes(x=time, y=Globe)) +
  geom_line() +
  geom_smooth(method = "gam",
              formula = y ~ s(x),
              color = alpha("red",0.5)) +
  facet_wrap( ~ month) +
  labs(
    title = "UAH global temp estimate by month",
    subtitle = "Based on v.6.0 of the dataset by Christy & Spencer",
    caption = "download data: https://www.nsstc.uah.edu/data/msu/v6.0/tlt/uahncdc_lt_6.0.txt"
  ) + theme(axis.text.x = element_text(angle = 90, vjust = 0.5))