11 October 2018

The method for calculating the globally averaged monthly means was revised. Previously, the monthly means were calculated by averaging the values of the global curve using the 48 equally spaced time steps that fell within each month. This was changed to interpolating at daily intervals and calculating the monthly mean for the daily values. This better represents the average during months where the mole fraction values are changing rapidly, such as June and September. Differences using the new method were less than 1 ppb from the previous method.

Uncertainty values for annual and monthly means were updated for the last few years.

05 February 2015

Global methane trends page activated.