Table 1.
Summary of background methods compared and evaluated for CO2 and CH4. References for all models can be found in the pertinent Methods section. *Models using Vulcan 3.0 as the flux in the near-field background use FFDAS 2015 and models using EPA use EDGAR v4.2 for the small region in Canada within our outer domain (Figure 2). **The right-most column indicates whether this background was evaluated in the synthetic data study (S; Sect. 3) or against actual (real) observations (R; Sect. 4).
| Abbreviation | Type of background |
yBGfar | yBGnear | yBG | Evaluation method** (S=synthetic, R=real) |
|---|---|---|---|---|---|
| CO2 | |||||
| Global-CTE | Global model sampling at inner domain boundary | CarbonTracker Europe | R | ||
| Global-CT | Global model sampling at inner domain boundary | CarbonTracker CT2019 | R | ||
| CT+V3+VPRM | Nested background | CarbonTracker CT2019 (1°x1°) | Vulcan 3.0* + VPRM (0.1°x0.1°) | yBGfar + yBGnear | R |
| CT+V3+CASA | Nested background | CarbonTracker CT2019 (1°x1°) | Vulcan 3.0* + CASA (0.1°x0.1°) | yBGfar + yBGnear | R |
| Upwind Lagged | Observations from upwind site | Sampled at the time of air mass exit | S | ||
| Upwind Aft | Observations from upwind site | Mean afternoon average from same day | S, R | ||
| Upwind Column | Observations from upwind site | Sampled from a vertical column (profile) | S, R | ||
| CH4 | |||||
| Global-CAMS | Global model sampling at inner domain boundary | CAMS CH4 v17r1s | R | ||
| CAMS+EPA | Nested background | CAMS CH4 v17r1s (2°x3°) | EPA 2012* (0.1°x0.1°) | yBGfar + yBGnear | R |
| CAMS+EDGAR | Nested background | CAMS CH4 v17r1s (2°x3°) | EDGAR v5.0 2015 (0.1°x0.1°) | yBGfar + yBGnear | R |
| Upwind Lagged | Observations from upwind site | Sampled at the time of air mass entrance | R | ||
| Upwind Aft | Observations from upwind site | Mean afternoon average from same day | R | ||
| Upwind Column | Observations from upwind site | Sampled from a vertical column | R | ||