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| Titel |
Assessment of the phenology impact on SVAT modelling through a crop growth model over a Mediterranean crop site : Consequences on the water balance under climate change conditions. |
| VerfasserIn |
S. Moulin, S. Garrigues, A. Olioso, F. Ruget, V. Desfonds, N. Bertrand, P. Lecharpentier, D. Ripoche, M. Launay, N. Brisson |
| 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 |
250064353
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| Zusammenfassung |
| In the coming years, water resources and vegetation production of Mediterranean areas will be drastically affected by climate changes as well as intense and rapid changes in the land use. The impact of climate and land-use changes on water balance and vegetation production can be analysed and predicted through land surface models, provided that the uncertainties associated to these models and to the data used to run them are evaluated. Vegetation phenology is generally poorly taken into account in land surface models and may be a substantial source of uncertainties for global change scenario studies.
In this paper, we discuss the improvement obtained in Soil Vegetation Atmosphere Transfer (SVAT) modelling by taking into account the phenology using a crop growth model, focusing on the water budget, over a Mediterranean crop site.
The STICS model (Brisson et al, 1998) is used to simulate crop processes (growth and development, taking into account water and nitrogen exchanges between the environment and the crop). STICS describes the vegetation phenology very accurately and was validated for many types of crop and various pedoclimatic conditions. The SVAT model being analyzed is the a-gs version (Calvet et al., 1998) of the ISBA model (Noilhan et al, 1989), which simulates the photosynthesis and calculates the plant biomass and the Leaf Area Index (LAI) using a simple growth model. In STICS, the phenology is driven by the sum of daily air temperatures, which is quite realistic, while in ISBA, the phenology is driven by the plant carbon assimilation. Measurements (vegetation characteristics, soil properties, agricultural practises, energy and water balance) performed in the lower Rhone valley experimental area (Avignon, France) are used as well as long series of climatic data (past records and future simulations).
In a first step, by running STICS and ISBA for maize and wheat crops with long series of climatic data, including future scenarios of climate (CLIMATOR project, Brisson et al, 2010), we show that the range of phenology simulated by ISBA is much wider than the one simulated by STICS. The large variability obtained with ISBA is not realistic and does not match with the genetic characteristics of the studied crops. In a second step, STICS and ISBA-a-gs are run over the same field of durum wheat cultivated during 5 years on a well instrumented site (Avignon crop observatory site). Their simulations are compared, in terms of LAI (driven by phenology), biomass (crop production), and evapotranspiration (water balance). The last step consists in forcing the SVAT model with the LAI simulated by STICS and assess the impact on the water and energy balance simulation accuracy. |
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