 |
| Titel |
Influence of soil moisture-climate and vegetation-climate interactions on European summer climate in regional climate model simulations |
| VerfasserIn |
Ruth Lorenz, Eric B. Jaeger, Sonia I. Seneviratne |
| Konferenz |
EGU General Assembly 2010
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250038606
|
|
|
|
|
|
| Zusammenfassung |
| Processes acting at the interface between the land surface and the atmosphere have a strong
impact on the European summer climate, particularly on extreme events. These processes are
to a large extent associated with soil moisture, but also with vegetation processes, since
plants’ transpiration is assumed to be the largest contributor to evapotranspiration in many
regions. This study investigates the role of soil moisture-atmosphere as well as
vegetation-atmosphere coupling for the European summer climate using regional climate
model (RCM) simulations.
On the one hand we use the model COSMO-CLM driven with ECMWF reanalysis and
operational analysis data to perform different RCM simulations. The set of experiments
includes a control run (CTL) with interactive soil moisture, and different sensitivity
experiments with prescribed soil moisture: a dry and a wet run to determine the impact of
extreme values of soil moisture, as well as experiments with lowpass-filtered soil
moisture from CTL to quantify the impact of temporal variability of soil moisture. Soil
moisture-climate interactions are found to have significant effects on temperature extremes in
the experiments and impacts on precipitation extremes are also identified. Case studies of
selected major summer heat waves reveal that intraseasonal and interannual variability of soil
moisture account for 5–30% and 10–40% of the simulated heat wave anomaly,
respectively.
On the other hand we perform simulations with COSMO-CLM2 to study the role of
vegetation-atmosphere coupling in particular for droughts and resulting feedbacks to the
regional climate. COSMO-CLM2 stands for a new version of the COSMO-CLM coupled to
NCAR’s Community land model. COSMO-CLM2 allows a detailed representation
of vegetation-climate interactions at the regional scale thanks to the possibility
of turning on and off different modules such as the carbon cycle (meaning that
with carbon cycle photosynthesis is calculated interactively and is prescribed in
the later case). We perform several experiments with and without soil moisture
feedbacks and including different land surface modules to investigate the resulting
vegetation-climate interactions with a focus on drought-climate feedbacks. In addition, by
comparing the results obtained with COSMO-CLM vs COSMO-CLM2 we highlight the
impact of the representation of detailed vegetation processes for land-atmosphere
feedbacks. |
|
|
|
|
|
|