Saturday, November 1, 2014

Global Mean Methane Moves Up Substantially: 2014 Year to Date IASI Mean Methane by Dekade and Month


During January to October 2014, global mean methane, as reported by the EUMETSAT METOP IASI instrument, jumped significantly above last year's readings. Global mean methane year to date, as measured by IASI through October, 2014 climbed to 1807.80 ppb or 6.38 ppb above 2013. 

The primary causes for these increases seem to be accelerated permafrost melt, some additional methane release in Arctic Ocean, forest fires in peat areas/wetlands in Canada and Russia, rice production in South Asia, palm oil production in Southeast Asia and oil and natural gas production in Africa and the Middle East. There are some areas of low altitude concentrations or surface flares at this point that are consistently apparent in the METOP/IASI imagery, that reach levels above 1950 ppb.

METOP 1-B and 2-A Description

There are two METOP satellites with the IASI methane measuring instrument currently in orbit. METOP 2, the second satellite in the production series, was actually launched first and is designated "A". The first satellite, METOP 1, was launched second and designated "B". Source:

To help keep their identity's straight, I have combined the two names as METOP 1-B and 2-A to help delineate their data and imagery. The METOP 2-A imagery was first made available through the NASA OSPO in 2012, as far as I am aware. METOP 1-B imagery was first made available through the OSPO on April 5, 2014, while the METOP 2-A satellite imagery was unavailable.

METOP 1-B vs 2-A IASI Methane Reading Comparison Variability

The methane readings of the METOP 1-B IASI instrument are generally 8-12 ppb higher than those of METOP 2-A. I am not sure why this is so, but presume that the METOP 1-B instrument readings may be more sensitive, or were originally calibrated differently. I hope someone who knows why will share with us. Both records are valuable in demonstrating trends in global mean methane.

Comparing IASI Mean Methane vs WMO, WDCGG, ESRL, AGAGE, etc.

The METOP IASI imagery provides a truly global perspective - advantageous to those interested in tracking methane. WMO, ESRL, AGAGE and individual stations collecting methane data are useful and repected for the following advantages:

1. They have collected CO2 and CH4 measurements for many years, providing a longer term trend than satellite data/imagery.
2. They are generally always available to track those measurements through time for specific locations.
3. They are able to measure CO2 and CH4 in a variety of weather conditions, including cloudiness, and temperature variability which can interfere with the IASI data collection and imagery.

However the WMO, ESRL, AGAGE and other agencies have some disadvantages.

1. The readings are for only a few specific locations, usually at the earth's surface.
2. Their readings do not extend into the atmosphere - in other words, methane concentrations any major distance above the surface are not measured.
3. Given the gaps in the network's global coverage, we have had to extrapolate what the global mean methane is based upon the stations in the network. Because areas not covered by the network may have lower methane readings, for example, then the global mean based upon the stations might be higher or lower than a more extensive network might report.

The advantages of METOP IASI data/imagery is that it is truly global, and provides 100 potential layers of methane measurement across the entire glove. This larger statistical sampling provides a better basis for measuring global mean methane.

One additonal advantage is that it is available almost real time, something not available from the ground based stations, except for CO2 from Mauna Loa as provided by Scripps and ESRL. However, this regrettably does not include daily CH4 readings.

The drawback is the since areas with cloudiness, or gaps in satellite coverage happen daily, the IASI data and imagery is still a sampling.

What will be closer to the ideal is if the the satelitte and earth based GHG measurement community comes to the point of merging the sources, then we will have a more robust and complete data set.

IASI Average Median Methane Collection and Trends

The following is the average mean methane readings summary by 10 day period (dekadal) and monthly from January 1 to October 31, 2014, for the METOP 2-A satellite, in comparison to 2013 as available.

What is being measured is the highest mean methane readings for each 12 hour period for each day's imagery and data as available. Given the nature of methane concentration, the altitude or millibar level for those highest means change throughout the year. Here is one image to illustrate what is being used from the OSPO. 

The highest global mean recorded by METOP 2-A IASI for a 12 hour period this year was 1829 ppb.

January, 2014

January is the next to lowest methane concentration month, and the monthly mean was 1 ppb above January, 2013.
Dekadal PPB Month PPB Average Month 2014 vs 2013 PPB
Jan 1-10, 2014 1793.35
Jan 11-20, 2014 1793.90
Jan 21-31, 2014 1792.76 1793.34 1.00

February, 2014

February's mean was the lowest in 2014 as it was in 2013. The methane mean difference between the year's was negligible at .13 ppb.

Dekadal PPB Month PPB Average Month 2014 vs 2013 PPB
Feb 1-10, 2014 1791.45
Feb 11-20, 2014 1790.86
Feb 21-28, 2014 1793.33 1791.88 0.13

March, 2014

The March methane mean collection was incomplete due to a METOP satellite anomaly which took it off line for about a month, beginning March 27, 2014. What follows is calculated upon the available imagery.

Dekadal PPB Month PPB Average Month 2014 vs 2013 PPB
Mar 1-10, 2014 1794.60
Mar 11-20, 2014 1796.35
Mar 21-26, 2014 1799.75 1796.90 0.35

The year to date mean methane was 1794.04 ppb, which was .49 ppb above January to March, 2013.

April, 2014

The METOP 2-A satellite was off-line for all of April, 2014 while its problem was analysed. No mean methane imagery was available through the OSPO.

May, 2014

METOP IASI became available again on May 20, 2014. The following monthly mean reflects imagery readings for the last 10 days of the month. It results in a reading 2.68 ppb above May, 2013, which is likely too high given the data gap.

Dekadal PPB Month PPB Average Month 2014 vs 2013 PPB
May 1-10, 2014 NA NA
May 11-20, 2014 NA NA
May 21-31, 2014 1799.50 1799.50 2.68

June, 2014

June, 2014 sees a significant increase in methane over the prior year, of 3.84 ppb. The difference may be linked to heatwaves and increased fires in Siberia and Canada.

Dekadal PPB Month PPB Average Month 2014 vs 2013 PPB
Jun 1-10, 2014 1799.27
Jun 11-20, 2014 1801.14
Jun 21-30, 2014 1802.44 1800.95 3.84

However, global mean methane to date through June 30, was only 1796.05 and only .41 ppb higher than 2013. At this point it seemed that 2014 and 2013 would not exhibit much of an increase in mean methane, but the next three months changed that perspective.

July, 2014

July witnessed an explosion of heat, drought and fire which accelerated methane release in July, 2014. The month average ended up 7.44 ppb above 2013. 

Dekadal PPB Month PPB Average Month 2014 vs 2013 PPB
Jul 1-10, 2014 1805.60
Jul 11-20, 2014 1812.90
Jul 21-31, 2014 1816.95 1811.82 7.44

Global mean methane for January through July, 2014 was 1799.01 ppb an increase to 2.12 ppb above the 2013 mean.

August, 2014

August witnessed the continued increase of fires, heat and drought which boosted global methane even more quickly. 
Dekadal PPB Month PPB Average Month 2014 vs 2013 PPB
Aug 1-10, 2014 1820.15
Aug 11-20, 2014 1821.55
Aug 21-31, 2014 1824.86 1822.19 8.07

The global mean methane year to date through August was 1802.67 or 3.63 ppb above 2013.

September, 2014

The major increase of global methane in September was troubling, but understandable as the same factors which impacted August's global mean methane continued. It is also possible that the warmer ocean water may have also influenced this increase in July through September. The last dekade of September had methane readings 15.45 ppb above 2013.

Dekadal PPB Month PPB Average Month 2014 vs 2013 PPB
Sept 1-10, 2014 1827.14
Sept 11-20, 2014 1825.46
Sept 21-30 2014 1825.90 1826.17 14.12

The global mean methane year to date through September 2014 was 1805.87 or 5.39 ppb above 2013, YTD.

October, 2014

This past month has witnessed continued elevated global mean methane due to global heat and increased methane in the northern hemisphere. It is clear that this increase may sustain through winter as darkness and temperatures fall in the northern hemisphere. 

Dekadal PPB Month PPB Average Month 2014 vs 2013 PPB
Oct 1-10, 2014 1823.37
Oct 11-20, 2014 1822.33
Oct 21-31, 2014 1820.14 1821.95 12.14

Global mean methane year to date through October, 2014 climbed to 1807.80 ppb or 6.38 ppb above 2013. 

What the rest of this year brings remains to be seen, but one thing is clear - methane continues its climb with serious implications for global warming.

Further reports will be created on a monthly basis.



Personal database of METOP/IASI imagery

1 comment: