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| Titel |
Land-climate feedbacks and climate extremes in the regional climate model COSMO-CLM2 |
| VerfasserIn |
R. Lorenz, E. L. Davin, S. I. Seneviratne |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250064956
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| Zusammenfassung |
| Land-climate feedbacks play a significant role for summer temperature variability and
extreme events, in particular in the context of climate change in Europe (e.g. Seneviratne et
al. 2010). These processes are to a large extent associated with soil moisture dynamics, but
also with vegetation processes, since plants’ transpiration is the largest contributor to
evapotranspiration in many regions.
We investigate here the role of land-climate feedbacks for regional climate in Europe
using the newly developed coupled biosphere-atmosphere regional climate model
COSMO-CLM2 (Davin et al. 2011). The model can be used either coupled to the Community
Land Model (CLM), an advanced land surface scheme (LSM), or to TERRA-ML, the native
land surface scheme in COSMO-CLM. We perform control runs and extreme soil moisture
experiments with both LSMs to investigate the influence of the LSM on the simulation of
land-climate feedbacks.
Overall, the results for the soil moisture experiments are consistent with the two LSMs.
However, using the more sophisticated LSM CLM reduces the sensitivity to the extreme soil
moisture experiments. This is in-line with a decreased temperature variability that reduces the
overestimation of temperature variability in the model. In addition, high temperatures are
better represented with the more sophisticated LSM. The influence of the land surface is
constrained to southern Europe with CLM. With TERRA-ML, regions of strong land-climate
coupling are more extended.
We also investigate the connection between heat waves and droughts in the simulations.
In regions where land-climate coupling is strong, both models underestimate the relationship
whereas they overestimate it in regions with weak land-climate feedbacks. In transitional
zones from strong to weak coupling this relationship is overestimated when using
TERRA-ML but well captured with CLM. Furthermore, we analyse simulated energy balance
anomalies over grassland and forests during heat waves and droughts and evaluate them with
observations.
These results highlight the importance of the correct representation of vegetation
processes and soil hydrology for the simulation of land-climate feedbacks in a regional
climate model. Biases in climate variability and extremes can be reduced with the use of a
more sophisticated land surface scheme and results in a more realistic representation of
land-climate feedbacks. The new COSMO-CLM2 is found to be a valuable tool to investigate
vegetation-climate interactions on the regional scale, although further improvement could still
be achieved.
References:
Davin, E.L, R. Stöckli, E.B. Jaeger, S. Levis, and S.I. Seneviratne (2011), COSMO-CLM2: a
new version of the COSMO-CLM model coupled to the Community Land Model. Climate
Dynamics, 37, 1889–1907, doi: 10.1007/s00382-011-1019-z.
Seneviratne, S.I., T. Corti, E.L. Davin, M. Hirschi, E.B. Jaeger, I. Lehner, B.
Orlowsky, and A.J. Teuling (2010), Investigating soil moisture-climate interactions in a
changing climate: A review. Earth-Science Reviews, 99, 3–4, 125–161, doi:10.1016/
j.earscirev.2010.02.004. |
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