sunspot.month | R Documentation |

## Monthly Sunspot Data, from 1749 to "Present"

### Description

Monthly numbers of sunspots, as from the World Data Center, aka SIDC.
This is the version of the data that will occasionally be updated when
new counts become available.

### Usage

sunspot.month

### Format

The univariate time series `sunspot.year`

and
`sunspot.month`

contain 289 and 2988 observations, respectively.
The objects are of class `"ts"`

.

### Author(s)

R

### Source

WDC-SILSO, Solar Influences Data Analysis Center (SIDC),
Royal Observatory of Belgium, Av. Circulaire, 3, B-1180 BRUSSELS
Currently at http://www.sidc.be/silso/datafiles

### See Also

`sunspot.month`

is a longer version of `sunspots`

;
the latter runs until 1983 and is kept fixed (for reproducibility as example
dataset).

### Examples

require(stats); require(graphics)
## Compare the monthly series
plot (sunspot.month,
main="sunspot.month & sunspots [package'datasets']", col=2)
lines(sunspots) # -> faint differences where they overlap
## Now look at the difference :
all(tsp(sunspots) [c(1,3)] ==
tsp(sunspot.month)[c(1,3)]) ## Start & Periodicity are the same
n1 <- length(sunspots)
table(eq <- sunspots == sunspot.month[1:n1]) #> 132 are different !
i <- which(!eq)
rug(time(eq)[i])
s1 <- sunspots[i] ; s2 <- sunspot.month[i]
cbind(i = i, time = time(sunspots)[i], sunspots = s1, ss.month = s2,
perc.diff = round(100*2*abs(s1-s2)/(s1+s2), 1))
## How to recreate the "old" sunspot.month (R <= 3.0.3):
.sunspot.diff <- cbind(
i = c(1202L, 1256L, 1258L, 1301L, 1407L, 1429L, 1452L, 1455L,
1663L, 2151L, 2329L, 2498L, 2594L, 2694L, 2819L),
res10 = c(1L, 1L, 1L, -1L, -1L, -1L, 1L, -1L,
1L, 1L, 1L, 1L, 1L, 20L, 1L))
ssm0 <- sunspot.month[1:2988]
with(as.data.frame(.sunspot.diff), ssm0[i] <<- ssm0[i] - res10/10)
sunspot.month.0 <- ts(ssm0, start = 1749, frequency = 12)