1. DTerEST, DTerIdF PAGE 1 Task 1 : to assess the refreshing potential of a VGR Task 2 : to develop relevant indicators dedicated to VGR environmental impacts Task 3 : to evaluate the spreading potential of the vegetation in urban zones The TERRACES project A collaborative work to understand the role of vegetative green roofs (VGR) in refreshing the urban ambiances (12/2012 – 12/2015) POSTER 13/ UCP 537

2. DTerEST, DTerIdF PAGE 2 Maeva Sabre, Julien Bouyer, David Ramier, Emmanuel Berthier, Jérémy Chollet, Ryad Bouzouidja, Rémy Claverie Task 1 : to assess the refreshing potential of a VGR The TERRACES project Qualifying and quantifying the changes in the urban energy balance using vegetative green roofs (VGRs)

3. PAGE 3 Task 1.1 : To measure the Energy balance and Evapotranspiration flux (ET) Task 1.2 : To model the Thermal and Hydrological balance of a VGR Task 1.3 : To assess the impact of Climate Change T E R R A C E S Task 1 : to assess the refreshing potential of a VGR EXPERIMENTATIONSSIMULATIONS DatabasePhysical propertiesCHOICE of the MODEL To build To assess To validateTo select PERFORMANCESIMPACT of CLIMATE CHANGE To predictTo evaluate

4. PAGE 4 Experimental sites T E R R A C E S Task 1.1 Energy balance and evapotranspiration Site 1 : Nancy (54) Site 2 : Trappes (78) Site 3 : Nantes (44)

5. PAGE 5 Experimental sites T E R R A C E S Task 1.1 Energy balance and evapotranspiration Site 3 : NantesSite 2 : TrappesSite 1 : Nancy SumPrec (mm) Tmean (°C)

6. PAGE 6 Experimental platforms T E R R A C E S Task 1.1 Energy balance and evapotranspiration Site 1 : Nancy (54) 600m² - EA (75m²) – Stock60 (28 m²)

7. PAGE 7 Experimental platforms T E R R A C E S Task 1.1 Energy balance and evapotranspiration Site 2 : Trappes (78) : 300m²

8. PAGE 8 Experimental platforms T E R R A C E S Task 1.1 Energy balance and evapotranspiration Site 3 : Nantes (44) (7 x 2.25 m²)

9. PAGE 9 T E R R A C E S Task 1.1 Energy balance and evapotranspiration Experimental platforms details

10. PAGE 10 T E R R A C E S Task 1.1 Energy balance and evapotranspiration Experimental platforms instrumentations Local meteorological stations (Air temperature, Humidity, wind speed, radiation, rainfall) Water outflow (tipping buckets water gauge) (Global : Nancy ; Local : Trappes, Nantes) Substrate water content (Time Differential Reflectometry) Substrate temperature (PT100 sensors at different depth) (Nancy, Nantes) Meteo-France meteorological stations Evolution of the plants cover Water quality analysis

11. PAGE 11 T E R R A C E S Task 1.1 Energy balance and evapotranspiration Calculations Water balance P = ET + R + D + ΔS P : cumulated precipitation [mm/h] ET : evapotranspiration flux [mm/h] R : cumulated runoff [mm/h] D : output flow of the system [mm/h] S : variation of the volumetric water content of the system [mm/h] Energy balance Q* = Qe + Qh + ΔQs Q* : radiation balance (solar, infrared exchanged at the surface) [W/m²] Qe: latent heat flux [W/m²] Qh : sensible heat flux [W/m²] ΔQs : variations of the storage heat [W/m²]

12. PAGE 12 T E R R A C E S Task 1.1 Energy balance and evapotranspiration Calculations LE : evapotranspiration flux [W/m²] L : latent heat flux [W/m²] h : the evapotranspiration chamber height [m] ρv : absolute humidity [g/m 3 ] T : time [s] Evapotranspiration flux ﾲ Outer Air T° ; RH Inner Air T° ; RH Absolute humidity Radiative flux 1 3 PMMA chamber walls Metal frame 2

13. PAGE 13 T E R R A C E S Task 1.1 Energy balance and evapotranspiration Experimental results Nantes 17/07/2013 Evapotranspiration fluxes (W/m²) on 3 sites Nantes 15/04/2014 Trappes 24/07/2013 Trappes 04/12/2013 Nancy 20/06/2013 Nancy 27/11/2013 Hours (UT) 14020040 10 12160

14. PAGE 14 T E R R A C E S Task 1.1 Energy balance and evapotranspiration Experimental results Comparison Water balance calculation / Evapotranspiration flux measurements (W/m²) on Nancy site

15. PAGE 15 T E R R A C E S Task 1.2 Simulation of the thermal and hydrological balance of VGR Choice of the model Choice of a coupled model (hydrological and thermal) to simulate the behavior of the system : soil-vegetation-atmosphere and its interaction at the city scale Green roof design for TEB-GREENROOF and associated physical process (de Munck et al., 2013)

16. PAGE 16 Scenarios from DRIAS database T E R R A C E S Task 1.3 Impact of climate change http://www.drias-climat.fr/ Scales : 8km, daily Parameters : air temperature, precipitation, humidity, wind speed… Periods : 1976 – 2005 ; 2021 - 2050 ; 2070 – 2100

17. PAGE 17 T E R R A C E S Future works -Analyze the platforms database for : albedo, emissivity, LAI, stomatal conductance… -Calibrate and validate the model with experimental data -Simulate the hydrological and thermal performances of the VGR -Use DRIAS to simulate the impact of climate change on the VGR’s performances - Put roof data into task 3 to see the district and town scale impacts

18. PAGE 18 DTerEST, DTerIdF THANK YOU FOR YOUR ATTENTION T E R R A C E S