1. SAG GHG Activities Ed Dlugokencky (chair), Oksana Tarasova (Secretariat), Ernst Brunke, David Griffith, Brad Hall, Sander Houweling, Armin Jordan, Hiroshi Koide, Paul Krummel, Toshinobu Machida, Justus Notholt, Doug Worthy

2. Documents: Approved or Reviewed by SAG GG Workshop Proceedings from 17 th WMO/IAEA Meetings on Carbon Dioxide, Other Greenhouse Gases, and Related Measurement Techniques (GGMT) Greenhouse Gas Bulletin updated: –Updated in 2013 and twice in 2014

3. GHG Bulletin Cover Stories 2013: Atmospheric CH 4 emissions 2014: Reducing RF (UN climate conference) and O 2 /N 2 (both include ocean acidification)

4. ISO Certification by GHG CCLs WMO signed International Committee for Weights and Measures (CIPM), Mutual Recognition Agreement (MRA) –NOAA prepared ISO-17025 compliant QS –QS reviewed by NIST 21-23 Jan., 2014 “Major” issues have been addressed –Presentation to SIM, April, 2015

5. Key Comparisons CCQM – K68: Ambient N 2 O in synthetic air –Organized by KRISS (Korean NMI) –Participation by 6 NMIs and CCL (NOAA) –All GC ECD and DID – no optical methods –Ambient = 310 to 330 ppb, no CO 2 –All results agree with reference values to 0.5% “…it is possible for this key comparison to offer a good traceability and a harmonization among the global distribution data of N 2 O.” –WMO compatibility goal: 0.1 ppb (1 δ)

6. Key Comparisons (cont.) CCQM – K82: Ambient CH 4 in air –Organized by BIPM –Each participant prepared 2 cylinders, nominally 1800 and 2200 ppb –All were analyzed at BIPM against common scale –NOAA about 2 - 4 ppb low compared to NMIs –WMO compatibility goal: 2.0 ppb (1 δ)

7. Key Comparisons (cont.) CCQM – K84: “Background” CO (350 ppb) –Tanks prepared by KRISS and sent to participants Very small cylinders used: all drifted considerably –Each participant measured cylinder –Results inconclusive

8. Priorities for SIP (1) Ensure measurement compatibility –Common standard scales → CCL –Participate in standard and measurement comparisons –Follow recommendations of GGMT community Encourage participants to use DBMS –Accommodates metadata and uncertainties –Facilitates reprocessing of data with changes to standard scales –Facilitates updates of data at WDCGG

9. Priorities for SIP (2) Expand measurement network –Surface and vertical profiles Climate sensitive regions Verify emissions-reduction treaties Evaluate satellite retrievals –Vertical profiles and Aircore necessary Support development of improved CTMs –More, better tracer measurements: SF 6 and 222 Rn