Scope, Context, BOGs
IPCC TFI Expert Meeting on Use of AtmosphericObservation Data in Emission Inventories
5-7 September 2022
WMO HQ, Geneva - Switzerland

IPCC TFI TSUOutline Expert meeting Scope Context:

 National Greenhouse Gas Inventories
 IPCC Categorization
 IPCC Methods

 Verification:

 Comparisons with atmospheric measurements
 Latest guidance in the 2019 Refinement

 BOG discussion

Expert Meeting Scopeassessing the use of Atmospheric Observation Data, andmodels, in the verification of national greenhouse gas (GHG)
inventories (NGHGI)NGHGINational Greenhouse Gas Inventories are composed by a timeseries of annual estimates of GHG emissions and removals,
from anthropogenic sources/sinks as categorized.

IPCC categories
IPCC categorisation of sources/sinks designed to cover:- All anthropogenic emissions and removals only
- Each and every anthropogenic source/sink of GHG emissions
while avoiding double counting.

IPCC methods
IPCC methods are generally based on bottom-up calculation ofestimates through the quantification of processes and activities
that cause GHG emissions and removals (i.e., activity data) atthe level of source/sink category and the application of
associated emission/removal factors.
Here emission/removal factors is a generic expression thatincludes the numerous parameters that characterize emission
sources, sinks and associated processes, technologies andpractices.

Verification
Verification of NGHGI estimates may occur at level of:- Activity data (AD)- Emission Factor (EF)- GHG estimates (as inferred through the IPCC method from AD and EF)
through comparison with independent datasets/methods(including those based on some recognized techniques of flux
measurement as chambers and stack measurements)

Verification
2019 Refinement (page 6.12 – Volume 1) In contrast to the othermethods described in this chapter, comparisons with atmosphericmeasurements are not established as a standard tool forverification to be applied by an inventory compiler. Still,
considerable scientific progress in this area needs to be noted andinventory compilers may wish to take advantage of the potential ofthis approach, as it gives independent data for verification

Comparisons with atmosphericmeasurements

Key steps to allow comparison of atmospheric measurementswith NGHGI’s sources/sinks (2019 Refinement, Volume 1, Box 6.5):
1. Confirm that observation-based and inventory estimates
represent the same time period and sources/areas (temporaland spatial gridding of the inventory and observation-based estimates).

2. Determine what data were used and how compare to theemission inventory (categories’ definitions)
3. Assess how the estimation procedure treats anthropogenic
and natural emissions, to confirm that the estimates compare withemissions included in the inventory

4. Confirm that seasonal variability of the emissions and othereffects have been considered in the comparison
5. Assess the uncertainties of the estimated emissions, andnote whether the discrepancy is statistically significant

Comparison with Regional/Global products
2019 Refinement, Volume 1

BOGs Discussion
4 BOGs to discuss same methodological elements for 4 different
portions of anthropogenic GHG fluxes:
BOG 1 – Focus on combustion CO2
BOG 2 – Focus on fugitive CH4
BOG 3 – AFOLU N2O, CH4, CO2
BOG 4 – F-gases
Each BOG to report to closing plenary

BOGs Discussion (1) Assess and critique recent estimation techniques that utilise
atmospheric observations as well as other new andoperational systems, platforms, instruments/sensors andmethods/models for their potential to be used for theverification of national inventory sectoral emission estimates,consistent with the guidance provided in the 2019
Refinement;

BOGs Discussion (2) Assess and evaluate successful examples of: comparisons between atmospheric observations andnational inventories that are consistent with good practiceprovided in the 2019 Refinement that have led toimplemented or planned improvements in nationalinventories;
 available examples where emission factors derived fromatmospheric observations have been incorporated into abottom-up inventory framework

BOGs Discussion (3) Assess the possibility that emerging datasets fromatmospheric observations could be used to test and verify
particular IPCC EF default values and associateduncertainties.

BOGs Discussion (4) Discuss the use of gridding (spatial and temporal) of NGHGIs
to allow comparison with atmospheric observation data.

BOGs Discussion (5) Discuss terminology and classifications of sources/sinks andassociated natural and anthropogenic GHG fluxes to find acommon understanding of consistency and differences inatmospheric observation data and GHG inventory estimates

Questions