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| Titel |
Interaction between soil moisture memory and different climate variables |
| VerfasserIn |
Tobias Stacke, Stefan Hagemann |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250109074
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| Publikation (Nr.) |
 EGU/EGU2015-8944.pdf |
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| Zusammenfassung |
| A large number of modelling studies show a potential impact of the soil moisture state on
regional climate on different time scales. Especially for short prediction periods,
perturbations of the soil moisture state may result in significant alteration of surface
temperature in the following season. The physical reasoning for such effects are usually
attributed to the soil moisture – temperature as well as the soil moisture – precipitation
feedbacks.
We designed a model experiment to investigate the time scale until the effect of arbitrary
soil moisture initialization is forgotten by the model. This time period is called soil moisture
memory and computed for different seasons based on an ensemble of nine, 3 year long,
simulations per season. These simulations are done using the coupled land-atmosphere model
ECHAM6-JSBACH, which is part of the Max Planck Institute for Meteorology’s Earth
System Model (MPI-ESM). Soil moisture memory was found to range between few days up
to several months. While the longest memory often coincides with either snow-covered
conditions or follows on monsoon periods, short memory is computed prior to snow-melt and
rainy seasons.
Additionally, the correlations between soil moisture memory and a number of surface
variables was investigated. We found that the magnitude of the initial soil moisture
perturbations explains at most 50% of the spatial variation in soil moisture memory while the
remaining variance is associated with soil properties and – even stronger – with
dynamical variables like surface temperature, evapotranspiration and runoff. This
effect differs for different seasons and soil moisture regimes which demonstrates the
complexity of soil moisture – climate interactions. Further analysis will be focused on the
re-occurrence of soil moisture memory after periods of insignificant memory and
the possibility of memory transfer between different land surface state variables. |
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