11th EMS, Berlin, 12-16 September 2011
The 'FluxSAP 2010' hydroclimatological
experimental campaign
over an heterogeneous urban area
presented by Yves Brunet
EPHYSE, INRA, Bordeaux, France
The FluxSAP team
P. Mestayer1,3, I. Bagga3, I. Calmet3, G. Fontanilles3, D. Gaudin3, J. H. Lee3, T. Piquet3,
J.-M. Rosant3, K. Chancibault2, L. Lebouc2, L. Letellier2, M.-L. Mosini2, F. Rodriguez2,
J.-M. Rouaud2, M. Sabre4, Y. Tétard4, A. Brut5, J.-L. Selves5, P.-A. Solignac5, Y. Brunet6,
S. Dayau6, M. Irvine6, J.-P. Lagouarde6, Z. Kassouk7, P. Launeau7, O. Connan8,
P. Defenouillère8, M. Goriaux8, D. Hébert8, B. Letellier8, D. Maro8, G. Najjar9, F. Nerry9,
C. Quentin9, R. Biron10, J.-M. Cohard10, J. Galvez11, P. Klein11
• 1Institut de recherche en sciences et techniques de la ville (IRSTV), FR CNRS 2488, BP 92101, Nantes,
France
• 2Département géotechnique, eau et risques (GER), IFSTTAR, Bouguenais, France
• 3Laboratoire de mécanique des fluides (LMF), UMR CNRS 6598, École Centrale de Nantes, France
• 4Département climatologie, aérodynamique, pollution et épuration (CAPE), CSTB, Nantes, France
• 5Centre d'études spatiales de la biosphère (CESBIO), UMR CNRS 5126, Toulouse, France
• 6Ecologie fonctionnelle et physique de l’environnement, UR1263 EPHYSE, INRA, Villenave d'Ornon,
France
• 7Laboratoire de planétologie et géodynamique de Nantes (LPGN), UMR CNRS 6112, Nantes, France
• 8Laboratoire de radioécologie de Cherbourg-Octeville (LRC), IRSN, Cherbourg, France
• 9Laboratoire des sciences de l'image de l'informatique et de la télédétection (LSIIT), UMR CNRS 7005,
Strasbourg, France
• 10Laboratoire d'étude des transferts en hydrologie et environnement (LTHE), UMR CNRS 5564,
Grenoble, France
• 11School of Meteorology, University of Oklahoma, Norman, OK 73072 USA
The context
VegDUD: the role of vegetation in sustainable urban development
Funded by the French National Research Agency (2010-2013)
Understanding and quantitatively assessing the impact of vegetation
in present and future urban development projects
Mixed urban areas (built, unbuilt, green surfaces)
Climatology, hydrology, energy control, environment
Location: city of Nantes, around the permanent observation site of
IRSTV ('Pin Sec' district)
Two ground and airborne measurement 'FluxSAP' campaigns:
2010, 2012
The objectives
FluxSAP objective: obtain reference data
for evaluating urban hydrology and microclimate models
for assessing quantitatively the role of vegetation on urban
climate
FluxSAP 2010 objective: test the methods allowing
to measure sensible heat and water vapour fluxes over a
heterogeneous urban district
to spatialize the measurements, taking into account landuse
heterogeneity
to test footprint models over an urban area
Loire river
Erdre river
Nantes region
'Pin Sec' measurement area
10 eddy covariance sensor systems
S
M
B
C
G E
W
D
5 LAS, 1 SAS
14 T-RH sensors at z = 2-3 m
10 piezometers, 8 T- profiles
Set-up summary
● T-RH (2 m)
⇑ EC mast
–– Scintillo
☐ GIS limits
Ground-based measurements
Airborne (13 flights) and handheld (140 refs) TIR
TIR measurements
20 flight lines
Hyspex sensor and inertial plateform
Hyperspectral airborne measurements
VNIR (400-1000 nm)
160 bands (4 nm)
0.6 m resolution
SWIR (1000-2500 nm)
256 bands (6 nm)
1.2 m resolution
95 ground measts
portable spectrometer
Meteo mast Tethered balloon
Emission sites
30 passive tracer dispersion experiments
Balloon DIAPEG
The meteorology (26 April – 7 june)
Temperature and humidity gradients
from T-RH and surface sensors
0
10
20
30
40
50
60
70
80
90
100
21-mai 22-mai 23-mai 24-mai 25-mai
hum
idité a
ir
(%)
10 11 12
13 14 15
16 17 18
19 Dunant
10
15
20
25
30
35
21-mai 22-mai 23-mai 24-mai 25-mai
tem
péra
ture
s a
ir
(°C
)
10 11 12
13 14 15
16 17 18
19 Dunant
Taupe 3
0
5
10
15
20
25
30
35
40
45
21-mai 22-mai 23-mai 24-mai 25-mai
Te
mp
éra
ture
s (
°C
)
Temp. air
surface
- 5 cm
- 35 cm
- 1 m
4 K 18 %
150 Wm-2
Heat flux measurements
with EC turbulent sensors
-100
0
100
200
300
400
500
1-May 6-May 11-May 16-May 21-May 26-May 31-May
date
se
nsib
le h
ea
t flu
x (
W m
-2)
G site_26 m G site_21 m E site_20 m M site_10m S site_32 m rain
Heat flux measurements
with LAS scintillometers
300 Wm-2
Preliminary conclusions
• Differences between measurement techniques but good
coherence between sites
• Differences between sites linked with different
distributions of land cover (buildings, pavement, bare
soil, high and low vegetation)
• Footprint analysis should allow us to identify the various
flux contributions and quantify the influence of
vegetation
Mestayer et al. (2011). Urban Climate News, 40:22-30 (www.urban-climate.org)
Mestayer et al. (2011). La Météorologie, 73:33-43 (www.smf.asso.fr)
Further analysis : the footprint issue
turbulent flux sensor
source area or footprint
wind U
Further analysis : the footprint issue
turbulent flux sensor
wind U L and D = f(z, z0, U, z/L…)
D L
Preparation for May-June 2012 campaign
More variable land cover within footprint
More EC masts over vegetated urban areas
More H2O turbulent sensors (Li-Cor)
More differentiated LAS paths (mineral, vegetal, mixed)
1 or 2 water vapour scintillometers?
Measure PTUV profile (0-150 m) with tethered balloon
Monitor water table (soil moisture profile)
11th EMS, Berlin, 12-16 September 2011
Thank you