ORCHIDEE

Physical Processes in Orchidée

Hydrological Cycle

• Evapotranspiration and Sensible heat flux : Sechiba N. Ducoudré, 1993 (de Noblet)

• Soil water flow and soil moisture content: P. de Rosnay (2002)

• Ground water flow and Groundwater: J. Polcher (2005)

Trenberth, 2007

Sechiba: Evaporation

• Impact of African and Amazonian Deforestation on climate: J. Polcher, 1994

• Comparison of Sechiba and Bats coupled to NCAR GCM: P. Peylin 1997

• Evapotranspiration: A. Barella-ortiz and T. d’Orgeval• Modelling of root water uptake: P. de Rosnay and J. Polcher (1998)

The simulated soil moisture is the most sensitive to water uptake parameter. This has been underlined in a study by Matthieu Guimberteau (2012)

Study over Illinois, M. Guimberteau, 2012

Soil Moisure IndexModel forced by NLDAS dataset

Soil moisture content:2 layers

I have introduced this 2 layers Model during Hui Ding thesis (1989)Its interest was to allow potential evapotranspiration after a rain.You must keep the upper layer thin enough:Drainage between upper and lower layer (A. Ducharne, 1998)

Influence of soil water holding capacity on water cycle (A. Ducharne, 2000)

Irrigation, and flood plains(Sechiba+GW Polcher)

• Irrigation P. de Rosnay, and flood plains T. d’Orgeval• Irrigation over Ganges bassin: delays monsoon onset (M. Guimberteau, 2012) (S. Shukla, et al, 2013: irrigation has to be included to

simulate realistically monsoon since 1960)

Guimberteau, 2010

Origin of the Warming hole? Irrigation from Ogallala aquifer?

De Angelis et al, 2010

How to improve soil moisture simulations?

We have to decrease the uncertainties on drought.

PDSI index is not reliable.Mo et al, 2011: study over USA.• Two examples

The role of resolution in the simulation of hydrological cycle over Iberian Peninsula

Sensitivity of the Hydro Cycle, Sylvie Vérant, 2004Resolution increases interception decreases, evpaoration does not change.But the soil moisture increases

Soil moisture in GCM experiment: de Rosnay parameterization (2002)

Comparison between 2 versions of Soil moisture Dependence on soil texture

Groundwater flow : effect on sea level height (NgoDuc et al, 2005)

Observation from Jason

In the Future: The decrease of uncertainties

• High resolution• Improve the prediction of agricultural drought. CESE: LA GESTION ET L’USAGEDE L’EAU EN AGRICULTURE: Mai, 2013

• Water Ressources (and sea level height): Konikov, 2011.

• Include all anthropogenic changes

The physical processes must be improved

Relation with Boundary layer:Ek, M., and L. Mahrt, 1991: A formulation for boundary-layer cloud cover.

Ann. Geophys., 9, 716–724.Holtslag, and M. Ek, 1996: Simulation of surface fluxes and boundary layer

development over the pine forest in HAPEX–MOBILHY.J. Appl. Meteor., 35, 202–213.

Cheruy et alRecycling of land precipitation: Risi et al

Thank you

Interaction between surface and ABL (Cheruy et al, 2013)