HR: 17:00h
AN: H42M-05 [PDF]
TI: The Role of Vegetation Dynamics on the Soil Water Balance in Water-Limited Ecosystems
AU: * Montaldo, N
EM: nicola.montaldo@polimi.it
AF: DIIAR, Politecnico di Milano, Piazza Leonardo da Vinci, 32, MILANO, 20133
Italy
AU: Rondena, R
EM: robi.rondena@libero.it
AF: DIIAR, Politecnico di Milano, Piazza Leonardo da Vinci, 32, MILANO, 20133
Italy
AU: Albertson, J D
EM: john.albertson@duke.edu
AF: Department of Civil and Environmental Engineering, Duke University, Box 90287; Hudson Hall, Durham, NC
27708-0287 United States
AU: Mancini, M
EM: marco.mancini@polimi.it
AF: DIIAR, Politecnico di Milano, Piazza Leonardo da Vinci, 32, MILANO, 20133
Italy
AB:
The structure and function of the vegetation regulates the exchange of mass, energy and momentum across the
biosphere-atmosphere interface. Vegetation dynamics are usually neglected, other than seasonal phenology, in land surface
models (LSMs). However, changes in vegetation densities, influencing the partitioning of incoming solar energy into sensible
and latent heat fluxes, can result in long-term changes in both local and global climates (e.g., precipitation and
temperature), which in turn will feedback to affect the vegetation growth. In semi-arid regions, this may result in
persistent drought and desertification, with substantial impacts on the human populations of these regions through reduction
in agricultural productivity and reduction in quantity and quality of water supply.
With an objective of finding a simple vegetation model able to accurately simulate the leaf area index (LAI) dynamics,
vegetation models of different level of complexity (e.g., including or not the modeling of the root biomass or the modeling
of the dead biomass) are developed and compared. The vegetation dynamics models are coupled to a LSM, with the vegetation
models providing the green biomass and the LAI evolution through time, and the LSM using this information in the computation
of the land surface fluxes and updating the soil water content in the root-zone. We explore the models on a case study of a
water limited grass field in California.
Results show that a simple vegetation model that simulates the living aboveground green biomass (i.e., with low
parameterization and computational efforts) is able to accurately simulate the LAI. Results also highlight the importance of
including the plant growth model in the LSM when studying the climate-soil-vegetation interactions and the impact of
watershed management practices on the scarce water resources over moderate to long time scales. The inclusion of the
vegetation model in the LSM is demonstrated to be essential for assessing the impact of climate change (e.g., decrease of
precipitation and increase of air temperature) on the water budget of a water limited region.
DE: 1620 Climate dynamics (3309)
DE: 1836 Hydrologic budget (1655)
DE: 1851 Plant ecology
DE: 1866 Soil moisture
DE: 3322 Land/atmosphere interactions
SC: Hydrology [H]
MN: 2003 Fall Meeting