![Hier klicken, um den Treffer aus der Auswahl zu entfernen](images/unchecked.gif) |
Titel |
WETCHIMP-WSL: Intercomparison of wetland methane emissions models over West Siberia |
VerfasserIn |
Joe Melton, Theodore Bohn |
Konferenz |
EGU General Assembly 2015
|
Medientyp |
Artikel
|
Sprache |
Englisch
|
Digitales Dokument |
PDF |
Erschienen |
In: GRA - Volume 17 (2015) |
Datensatznummer |
250104634
|
Publikation (Nr.) |
EGU/EGU2015-4064.pdf |
|
|
|
Zusammenfassung |
Wetlands are the world’s largest natural source of methane, a powerful greenhouse gas.
The strong sensitivity of methane emissions to environmental factors such as soil
temperature and moisture has led to concerns about potential positive feedbacks
to climate change. This risk is particularly relevant at high latitudes, which have
experienced pronounced warming and where thawing permafrost could potentially
liberate large amounts of labile carbon over the next 100 years. However, global
models disagree as to the magnitude and spatial distribution of emissions, due to
uncertainties in wetland area and emissions per unit area and a scarcity of in situ
observations. Recent intensive field campaigns across the West Siberian Lowland
(WSL) make this an ideal region over which to assess the performance of large-scale
process-based wetland models in a high-latitude environment. Here we present the
results of a follow-up to the Wetland and Wetland CH4 Intercomparison of Models
Project (WETCHIMP), focused on the West Siberian Lowland (WETCHIMP-WSL).
We assessed 21 models and 5 inversions over this domain in terms of total CH4
emissions, simulated wetland areas, and CH4 fluxes per unit wetland area and compared
these results to an intensive in situ CH4 flux dataset, several wetland maps, and two
satellite inundation products. We found that: a) despite the large scatter of individual
estimates, 12-year mean estimates of annual total emissions over the WSL from forward
models (5.34 ±0.54 Tg CH4 y-1), inversions (6.06 ±1.22 Tg CH4 y-1), and in
situ observations (3.91 ±1.29 Tg CH4 y-1) largely agreed; b) forward models
using inundation products alone to estimate wetland areas suffered from severe
biases in CH4 emissions; c) the interannual timeseries of models that lacked either
soil thermal physics appropriate to the high latitudes or realistic emissions from
unsaturated peatlands tended to be dominated by a single environmental driver
(inundation or air temperature), unlike those of inversions and more sophisticated forward
models; d) differences in biogeochemical schemes across models had relatively
smaller influence over performance; and e) multi-year or multi-decade observational
records are crucial for evaluating models’ responses to long-term climate change. |
|
|
|
|
|