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| Titel |
Climate-methane cycle feedback in global climate model model simulations forced by RCP scenarios |
| VerfasserIn |
Alexey V. Eliseev, Sergey N. Denisov, Maxim M. Arzhanov, Igor I. Mokhov |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250072210
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| Zusammenfassung |
| Methane cycle module of the global climate model of intermediate complexity developed at
the A.M. Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences (IAP
RAS CM) is extended by coupling with a detailed module for thermal and hydrological
processes in soil (Deep Soil Simulator, (Arzhanov et al., 2008)). This is an important
improvement with respect with the earlier IAP RAS CM version (Eliseev et al., 2008) which
has employed prescribed soil hydrology to simulate CH4 emissions from soil. Geographical
distribution of water inundated soil in the model was also improved by replacing the older
Olson’s ecosystem data base by the data based on the SCIAMACHY retrievals
(Bergamaschi et al., 2007). New version of the IAP RAS CM module for methane
emissions from soil is validated by using the simulation protocol adopted in the
WETCHIMP (Wetland and Wetland CH4 Inter–comparison of Models Project).
In addition, atmospheric part of the IAP RAS CM methane cycle is extended by
temperature dependence of the methane life–time in the atmosphere in order to mimic
the respective dependence of the atmospheric methane chemistry (Denisov et al.,
2012).
The IAP RAS CM simulations are performed for the 18th–21st centuries according with
the CMIP5 protocol taking into account natural and anthropogenic forcings. The new IAP
RAS CM version realistically reproduces pre–industrial and present–day characteristics of
the global methane cycle including CH4 concentration qCH4 in the atmosphere and CH4
emissions from soil. The latter amounts 150 - 160 TgCH4-yr for the late 20th century and
increases to 170 - 230 TgCH4-yr in the late 21st century. Atmospheric methane
concentration equals 3900 ppbv under the most aggressive anthropogenic scenario RCPÂ 8.5
and 1850 - 1980 ppbv under more moderate scenarios RCPÂ 6.0 and RCPÂ 4.5.
Under the least aggressive scenario RCPÂ 2.6 qCH4 reaches maximum 1730 ppbv in
2020s and declines afterwards. Climate change impact on the methane emissions
from soil enhances build up of the methane stock in the atmosphere by 10 - 25%
depending on anthropogenic scenario and time instant. In turn, decrease of methane
life–time in the atmosphere suppresses this build up by 5 - 40%. The net effect is
uncertain but small in terms of resulting additional greenhouse radiative forcing. This
smallness is reflected in small additional (relative to the model version with both
methane emissions from soil and methane life–time in the atmosphere fixed at their
preindustrial values) near–surface warming which globally is not larger than 1 K, i.e,
-¤ 4% of warming exhibited by the model version neglecting climate–methane cycle
interaction.
References
[1]Â Â Â M.M. Arzhanov, P.F. Demchenko, A.V. Eliseev, and I.I. Mokhov. Simulation
of characteristics of thermal and hydrologic soil regimes in equilibrium numerical
experiments with a climate model of intermediate complexity. Izvestiya, Atmos.
Ocean. Phys., 44(5):279–287, 2008. doi: 10.1134/S0001433808050022.
[2]   P. Bergamaschi, C. Frankenberg, J.F. Meirink, M. Krol, F. Dentener,
T. Wagner, U. Platt, J.O. Kaplan, S. Körner, M. Heimann, E.J. Dlugokencky, and
A. Goede. Satellite chartography of atmospheric methane from SCIAMACHY on
board ENVISAT: 2. Evaluation based on inverse model simulations. J. Geophys.
Res., 112(D2):D02304, 2007. doi: 10.1029/2006JD007268.
[3]Â Â Â S.N. Denisov, A.V. Eliseev, and I.I. Mokhov. Climate change in the IAP RAS
global model with interactive methane cycle under RCP anthropogenic scenarios.
Rus. Meteorol. Hydrol., 2012. [submitted].
[4]Â Â Â A.V. Eliseev, I.I. Mokhov, M.M. Arzhanov, P.F. Demchenko, and S.N. Denisov.
Interaction of the methane cycle and processes in wetland ecosystems in a climate
model of intermediate complexity. Izvestiya, Atmos. Ocean. Phys., 44(2):139–152,
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