9.5
Including tropical croplands in a terrestrial biosphere model: application to West Africa
PAPER WITHDRAWN
Alexis Berg, LOCEAN-IPSL, Paris, France; and B. Sultan and N. De Noblet
Studying the large-scale relationships between climate and agriculture
rises two different issues: the impact of climate on crops, and the potential
feedbacks to climate from croplands. Extending existing Dynamic Global
Vegetation Models to account accurately for croplands offers a relevant and
consistent framework to address this twofold issue.
By introducing into the terrestrial biosphere model ORCHIDEE (IPSL)
parametrisations from the crop model SARRAH (CIRAD) which is calibrated over
the west african region, we developed an original large-scale model for tropical crops,
ORCH-mil. It realistically simulates growth and yield of millet when compared
to the original crop model on an experimental station in Senegal. The model
is then applied over West Africa using a 36-year climate reanalysis dataset.
The model is tested against national yields from the FAO database. The
ability of the model to simulate the spatial and temporal variability of
millet yields is assessed, as well as its ability to model the observed
relationship between weather and yields. Effect of crop duration on the skill
of the model is examined. Effects of croplands on surface energy fluxes are also considered. Results underline the need for some further
development and validation of the model. In the frame of the AMMA project (African Monsoon Multidisciplinary Analysis), potential applications of the model
include seasonal predictions of tropical cereals yields, agricultural impacts of
climate change in West Africa, and impacts of agricultural land-use on the
land surface Water and Carbon budgets over West Africa.
Session 9, Atmospheric Modeling and Data Assimilation of Land-Surface Climate Interactions
Thursday, 1 May 2008, 1:30 PM-3:15 PM, Floral Ballroom Jasmine
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