While some claim the spike occurred in the Laptev or ESS, we do not have location data from the image to confirm that - it is a presumption. If those making the claims had the actual location data to support the assumption it will be helpful. Even if the spike is located over the Laptev/ESS, the 586 mb layer with the spike is not on the surface, but approximately 14,400 feet or 4,400 meters above the surface in a constantly moving airmass. A review of the earlier Methane Tracker imagery through time clearly illustrates that fact.
Another option is that the methane spike may have been associated with a cold air mass over Russia on October 25-28 with record low temps. Here are the October 25 and 27 Climate Reanalyzer images to illustrate the cold temp anomaly, that matched with a center of circulation visible in the cloud pattern in the IASI imagery that follows:
To illustrate the transitory nature of the spike, here are four days (October 25-28, 2014) of the METOP 2-A IASI imagery for 586 mb. Note the highest range PPB reading variation for this altitude (in the "Range" section of each image) to illustrate the changes in concentration - given the dynamics discussed above.
Here is the 415 ppb "spike" image from October 25 pm to October 26 am, as displayed elsewhere - without context. Note the swirl of circulation over Siberia, which would potentially concentrate CH4 for this spike reading.Note the following 12 hours experience a 317 ppb drop.
Here are the October 27, 2014 images. The highest CH4 readings at 586 mb are still in the 2300's ppb.
Here are the October 28, 2014 images, and note that the highest ppb are back in the 2200's.
If one collects these images on a daily basis, you will see ongoing daily, dekadal and monthly variation and spikes at any mb level in the IASI readings.
What is far more meaningful - and concerning - are the changes in mean methane readings. In other words, the mean or average annual increase and variance of this year over 2013 and prior years on a dekadal, monthly and annual basis. The global mean methane measure in each of the images above provides a better understanding of global methane concentration change - as collected through time. The post that compares global mean methane readings for 2014 to 2013 to October 31st follows.
OPSO - METOP IASI: