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| Titel |
The combined influence of the main European circulation patterns on carbon uptake by ecosystems |
| VerfasserIn |
Ana Bastos, Célia Gouveia, Ricardo Trigo |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250086239
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| Publikation (Nr.) |
 EGU/EGU2014-67.pdf |
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| Zusammenfassung |
| Understanding how natural climate variability affects carbon uptake by land and ocean pools
is particularly relevant to better characterize human impact on the carbon cycle. Recently, we
have contributed to assess the major role played by the El-Niño/Southern Oscillation in
driving inter-annual variability (IAV) of carbon uptake by land ecosystems and significantly
influencing global CO2 air-borne fraction [1]. Despite the prominent role played by
ENSO, other important teleconnections on the hemispheric scale have deserved less
attention.
On the European scale, the main mode of variability is the North-Atlantic Oscillation
(NAO), which controls storm tracks position and drives changes in temperature and
precipitation over the whole region, affecting vegetation dynamics [2]. Besides NAO, a few
additional large scale circulation patterns the Scandinavian (SC) and East-Atlantic (EA)
Patterns, are also known to influence significantly the European climate [3]. Different
combinations of these teleconnection polarities have been recently shown to modulate the
overall role of the NAO impact location and strength, thus affecting winter temperature and
precipitation patterns over Europe [4].
This work aims to answer the following questions:
(i) how do NAO, EA and SC affect vegetation carbon uptake IAV?
(ii) do the interactions between these three modes have a significant impact on land CO2
IAV?
(iii) what is the contribution of the different physical variables to ecosystems’ response to
these modes?
(iv) how well do the state-of-the-art Earth System Models (ESMs) from CMIP5 represent
these climate variability modes and the corresponding carbon fluxes?
We first analyze observational data to assess the relationships between the different
combinations of NAO, SC and EA polarities and IAV of gross and net primary production
(GPP and NPP, respectively), as well as the most relevant driving factors of ecosystem’s
response to those variability patterns. Although the winter state of NAO has, as expected, the
largest impact on European-wide carbon uptake patterns, the other modes appear to have a
strong influence in particular regions, presenting overlapping effects with different signs
which are due to differentiated responses to temperature and precipitation variability. We then
rely on the historical experiment (CO2 concentration driven) of 12 ESMs from CMIP5 to
assess the capability of those models to represent NAO, EA and SC patterns, the associated
physical variables as well as the corresponding land carbon fluxes. Although all
models simulate NAO reasonably well, and most represent EA and SC patterns
satisfactorily, the response of the carbon cycle to these variability modes still needs further
improvements.
References
[1]Bastos, A., Running, S. W., Gouveia, C.M., Trigo, R.M., (2013): J. Geophys.
Res. Biogeosci.,118, 1247-1255, doi:10.1002/jgrg.20100.
[2]Gouveia, C.M., Trigo, R. M., DaCamara, C. C., Libonati, R., Pereira, J. M. C.
(2008): Int. J. Climatol., 28, 1835–1847, doi: 10.1002/joc.1682.
[3]Trigo R.M., Valente M.A., Trigo I.F., Miranda P.M., Ramos A.M., Paredes D.,
García-Herrera R. (2008): Annals of the New York Academy of Sciences, 1146,
212–234, doi: 10.1196/annals.1446.014.
[4]Comas-Bru, L., McDermott, F. (2013): Q.J.R. Meteorol. Soc., doi:
10.1002/qj.2158. |
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