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Dear all,<br>
<br>
Here is an opportunity for a Post-doc position on numerical fluid
mechanics in INRA - EPHYSE,
Bordeaux, France. Details are as follows:<br>
<br>
<b>Post-Doctorate position : Microclimatic fields in heterogeneous
terrain</b><br>
<br>
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.<br>
<br>
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.<br>
<br>
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.<br>
<br>
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.<br>
<br>
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.<br>
<br>
Keywords: Microclimatology, fluid mechanics, spatial heterogeneity,
numerical simulations, large-eddy simulation, ARPS<br>
<br>
Contact : Sylvain Dupont, e-mail : <a class="moz-txt-link-abbreviated"
href="mailto:sdupont@bordeaux.inra.fr">sdupont@bordeaux.inra.fr</a>,
Tél. : +33
5 57 12 24 33<br>
<br>
Location : INRA, Unité EPHYSE, BP 81, 33883 Villenave d’Ornon cedex,
France.<br>
<br>
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.<br>
<br>
Contract: 24 months fixed term contract with a monthly gross salary of
2150€.<br>
<br>
<big><big><b>The deadline for submitting your candidature is July 31st,
2006.</b></big></big>
<pre class="moz-signature" cols="72">--
__________________________
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
__________________________</pre>
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