Temperature Update - December 2017, RSS

The RSS satellite data has been released for the end of 2017, so here is my summary.

Temperatures

According to RSS 4.0 the anomaly Lower Troposphere was 0.59 °C in December, compared with the 1979-1998 reference period. This makes December 2017 the 2nd warmest December in the RSS data set.

Here's the traditional 12 month smoothed average.

This leaves the average anomaly for 2017 as 0.634°C, making 2017 the 2nd warmest year on record, beating only by 2016.

predictions

Last month the prediction was for 2017 to finish with an anomaly of 0.627 ± 0.027°C. The reported value is 0.634°C, 0.007°C warmer than predicted, well within the prediction interval.

This graph shows a month by month summary of the predicted annual value, along with a gray ribbon showing the 95% prediction interval. (Note, as always these predictions are recalculated with the current data.)

As with the UAH predictions, my model consistently underestimated the final figure, but it was within the prediction intervals for each month.

Here is the comparison with the method I was using in 2016.

As with UAH, the new method which includes an assumed linear trend, was consistently better than the old method, which only looked at the year to date temperatures. Not only was the new method closer to the actual value, especially at the start of the year when it roughly halved the error, but it also gave tighter prediction intervals. (With the UAH predictions there was not much difference in terms of the prediction intervals. I suspect this is due to UAH having less of a linear warming trend.)