ORCHIDEE-Dev : January 8th, 2013 Theme #1 Water cycle, river flows, water quality and interactions with biosphere under future climate Réservoir souterrain Réservoir fleuve 10 0 m 10 1 m 10 5 m D Rs E Soil : Choisnel vs. CWRR Temperature, permafrost River routing, wetlands, biogeochemical cycles ET and climate interactions 2 sessions : Hydrology and Cold Processes

ORCHIDEE-Dev : January 8th, 2013 Theme #1 Water cycle, river flows, water quality and interactions with biosphere under future climate Session Hydrology : Anaïs Barella : Potential evaporation computation through an unstressed surface energy balance and its sensitivity to climate change effect Matthieu Guimberteau : The Amazon River Basin under change Marta Camino : Factors influencing DOC leaching from terrestrial ecosystems Aurélien Campoy Jan Polcher

- Global effect of irrigation and its impact on the onset of the Indian summer monsoon (Guimberteau & al., 2012, Clim. Dyn.) => when irrigation is activated : - delayed monsoon onset + weakened monsoon - summer precipitation increase (decrease) over western (eastern) Mississippi - A comprehensive approach to analyze discrepancies between land surface models and in-situ measurements: a case study over the US and Illinois with SECHIBA forced by NLDAS (Guimberteau & al., 2012, HESS) => improvement of simulated soil moisture through sensitivity tests of vegetation parameters + use of a different evapotranspiration computation and precipitation input - Discharge simulation in the sub-basins of the Amazon using ORCHIDEE forced by new datasets (Guimberteau & al., 2012, HESS) => improvement of simulated discharges with new data sets of daily precipitation forcing & floodplains/swamps spatial coverage - Future changes in precipitation and impacts on extreme streamflow over Amazonian sub-basins (Guimberteau & al., sub. to ERL) => see next slide Matthieu GUIMBERTEAU Post-doc IPSL-SISYPHE-LSCE Work on ORCHIDEE: since 2006 Main research topics: hydrology, water cycle, irrigation, streamflow, LSM assessment, Amazonian hydrology Mail: Web page: / Past researches Present research: Amazon River basin - 2lay./11lay. hydrology comparison and assessment - Improvement of hydrology: soil & rooting depths, soil hydraulic properties - Soil water infiltration according to the offline precipitation spread over the time-step - Impact of LUC and Climate Change on hydrology In the framework of the AMAZALERT project

Future changes in precipitation and impacts on extreme streamflow over Amazonian sub-basins (Guimberteau & al., sub. to ERL) Construction of future climate forcings (delta downscaling method): for each of the 8 AR4 GCMs => 20yr-climatology for each variable => computation of anomalies between future and present-time => addition of anomalies on each 6h NCC time-step (NCC previously corrected by daily precipitation dataset) ORCHIDEE forced by 8 different future climate forcings => comparison with present-time simulation Mean relative change (%) of the low flows for 16 stations (for each of the eight simulations, differences performed between each future year and the present-time seasonality) Result for under SRESA1B scenario Number of GCMs out of eight that project a JJA precipitation increase Southern sub-basins (with low runoff coefficients (R/P)) will become more responsive to precipitation change than the western sub-basins (with high runoff coefficients) Western and north-western sub-basins: more responsive to evaporation change

Factors influencing DOC leaching from terrestrial ecosystems Main focus: to incorporate a module of dissolved organic carbon (DOC) leaching from terrestrial ecosystems into ORCHIDEE. - Two phases: 1) A database development in order to establish quantitative relationships between terrestrial DOC concentration and fluxes and their drivers (UA). 2) Model development: improve process description to incorporate DOC leaching in ORCHIDEE(LSCE). The observed relationships from the database will be used to parameterize in ORCHIDEE the spatial and temporal (intra and inter-annual) variability of DOC amongst ecosystems types. Figure 1. Vertical pattern of DOC concentration in soil solution for broadleaved and coniferous forest sites. Supervisors: Sebastiaan Luyssaert, Philippe Ciais (LSCE), Ivan Janssens (UA) Marta Camino

SOIL MODULE IN ORCHIDEE Factors influencing DOC leaching from terrestrial ecosystems Tasks to develop in ORCHIDEE: 1. Changes in code in ORCHIDEE: 1.1. Include DOC as a carbon pool (equations for decomposition, sorption/desorption) –Bertrand SWC and Drainage from 11 layers Hydrological Module (DOC concentration and fluxes) –Agnes, Matthieu, Aurélien Discretization of C and DOC in soil (together with tracers) -Camille- 2. Parameterization (literature/database results) 3. Validation (stream DOC fluxes) Marta Camino