[Oppslist] Post-doc position fluid mechanics INRA Bordeaux France

[Sylvain DUPONT]

Dear all,

Here is an opportunity for a Post-doc position on numerical fluid 
mechanics in INRA - EPHYSE, Bordeaux, France. Details are as follows:

*Post-Doctorate position : Microclimatic fields in heterogeneous terrain*

Forested landscapes are often characterized by a large spatial 
variability due to the presence of clearings, roads, forest patches of 
various heights, etc., constituting a patchwork that may be complex. 
This fragmentation induces a spatial variability in the dynamic (wind, 
turbulence) and thermodynamic (temperature, moisture) fields, and thus a 
microclimatic variability acting on transfer mechanisms, gaseous 
diffusion, deposition and life time of biotic particles, ground water 
availability and thus on the functioning and growth of vegetated canopies.

The objective of the present Post-Doctorate position is to study for the 
first time the microclimatic variability induced by simple 
clearing-to-canopy and canopy-to-clearing transitions from numerical 
experiments at fine resolution by using a Large Eddy Simulation (LES) 
approach. The LES approach allows one to have access to instantaneous 
three-dimensional fields, and thus to reproduce the turbulent structures 
which are essential in the transfer processes of momentum and scalars 
such as heat, vapour and CO2 at the canopy-atmosphere interface. For 
this purpose, the Advanced Regional Prediction System (ARPS) developed 
by the University of Oklahoma/CAPS (USA) will be used. It has the 
advantage of being a full weather model, so that it explicitly simulates 
all dynamic and thermodynamic fields of the atmosphere. Moreover, the 
code was recently modified by the EPHYSE Unit (INRA) in order to 
simulate the turbulent flow within and above heterogeneous canopies from 
such an LES approach.

This new version of ARPS has been only validated so far in neutral and 
dry atmosphere over homogeneous forested canopies and simple 
forest-clearing-forest patterns against field and wind-tunnel 
measurements. In the current version of ARPS, the humidity and heat 
fluxes from the vegetation are calculated only at the ground-atmosphere 
interface. Therefore, we plan first to modify ARPS in a simple manner 
from the current surface model in order to solve the heat, humidity and 
radiation fluxes at various levels within the canopy. The model will 
then be applied to a simple clearing-forest transition; in parallel to 
this numerical experiment, measurements will be performed on the Bray 
site (Maritime pine) near Bordeaux, France. In a following stage, the 
modelling of the physical and biological processes within the canopy 
(stomatal resistance, radiation, etc.) will be refined from the Musica 
model developed at EPHYSE (Ogée and al, 2003). A sensitivity study to 
these parameterisations will be performed.

This new version of ARPS should become the first model able to simulate 
the instantaneous microclimatic fields at the level of a heterogeneous 
canopy. This tool can then be used for many multidisciplinary 
applications related to the functional impacts of landscape 
heterogeneities. It will be used in particular to test the assumptions 
made within the framework of landscape models such as SEVE (a French 
initiative), which is used on a larger scale.

Ogée J., Brunet Y., Loustau D., Berbigier P., Delzon S., 2003. MuSICA, a 
CO2, water and energy multi-layer, multi-leaf pine forest model: 
evaluation from hourly to yearly time scales and sensitivity analysis. 
Global Change Biology, 9, 697-717.

Keywords: Microclimatology, fluid mechanics, spatial heterogeneity, 
numerical simulations, large-eddy simulation, ARPS

Contact : Sylvain Dupont, e-mail : sdupont at bordeaux.inra.fr, Tél. : +33 
5 57 12 24 33

Location : INRA, Unité EPHYSE, BP 81, 33883 Villenave d'Ornon cedex, France.

Candidature conditions: (i) no nationality conditions, (ii) to be doctor 
at recruitment date (French doctorate, PhD or foreign doctorate of 
equivalent level), (iii) no previous research activity in the foreseen 
INRA centre, (iv) to be available for recruitment on October 1st, 
November 1st or December 1st 2006, and (v) to fill an application.

Contract: 24 months fixed term contract with a monthly gross salary of 
2150EUR.

*The deadline for submitting your candidature is July 31st, 2006.*

-- 
__________________________

Sylvain Dupont
INRA - EPHYSE
BP 81
33883 Villenave d'Ornon
FRANCE
Ph:  +33 (0)5 57 12 24 33
Fax: +33 (0)5 57 12 24 20

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