 |
| Titel |
Constraining Swiss Methane Emissions from Atmospheric Observations:
Sensitivities and Temporal Development |
| VerfasserIn |
Stephan Henne, Markus Leuenberger, Martin Steinbacher, Werner Eugster, Frank Meinhardt, Peter Bergamaschi, Lukas Emmenegger, Dominik Brunner |
| Konferenz |
EGU General Assembly 2017
|
| Medientyp |
Artikel
|
| Sprache |
en
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250149527
|
| Publikation (Nr.) |
 EGU/EGU2017-13883.pdf |
|
|
|
|
|
| Zusammenfassung |
| Similar to other Western European countries, agricultural sources dominate the methane
(CH4) emission budget in Switzerland. ‘Bottom-up’ estimates of these emissions are still
connected with relatively large uncertainties due to considerable variability and uncertainties
in observed emission factors for the underlying processes (e.g., enteric fermentation, manure
management).
Here, we present a regional-scale (∼300 x 200 km2) atmospheric inversion study of CH4
emissions in Switzerland making use of the recently established CarboCount-CH network
of four stations on the Swiss Plateau as well as the neighbouring mountain-top
sites Jungfraujoch and Schauinsland (Germany). Continuous observations from all
CarboCount-CH sites are available since 2013. We use a high-resolution (7 x 7 km2)
Lagrangian particle dispersion model (FLEXPART-COSMO) in connection with two
different inversion systems (Bayesian and extended Kalman filter) to estimate spatially and
temporally resolved CH4 emissions for the Swiss domain in the period 2013 to 2016. An
extensive set of sensitivity inversions is used to assess the overall uncertainty of our inverse
approach.
In general we find good agreement of the total Swiss CH4 emissions between our
‘top-down’ estimate and the national ‘bottom-up’ reporting. In addition, a robust emission
seasonality, with reduced winter time values, can be seen in all years. No significant
trend or year-to-year variability was observed for the analysed four-year period,
again in agreement with a very small downward trend in the national ‘bottom-up’
reporting.
Special attention is given to the influence of boundary conditions as taken from different
global scale model simulations (TM5, FLEXPART) and remote observations. We find that
uncertainties in the boundary conditions can induce large offsets in the national total
emissions. However, spatial emission patterns are less sensitive to the choice of boundary
condition.
Furthermore and in order to demonstrate the validity of our approach, a series of inversion
runs using synthetic observations, generated from ‘true’ emissions, in combination with
various sources of uncertainty are presented. |
|
|
|
|
|
|