DayCent-Chem Overview

Melannie HartmanNREL

CANS Project MeetingFeb. 15-17, 2006Sylvan Dale Ranch

Loveland, CO

John Fielder

SO2

NOx

Why was DayCent-Chem developed?

• Biological cycling of nutrients is important to predicting deposition effects on stream/soil chemistry.

• Management of forests, croplands, and grasslands built into Century.

• Daily time step.• Model of intermediate

complexity.John Fielder

History of DayCent, cont’d

2001

CENTURYversion 5

monthly, C++

DayCentversion 5

daily, C++

DayCentversion 4

daily FORTRAN/C

DayCentversion 4.5

dailyFORTRAN/C

DayCent-Chem

daily, C++

PHREEQCversion 2.7, C

KeoughDel Grosso

Parton2001-present

Hillinski1998

CENTURYversion 4monthly

FORTRAN

http://www.nrel.colostate.edu/projects/century5/

Parton, Ojima,

Hartman 1994

Hartman, Baron,

2003-present

Parton, Ojima,

Schimel 1980s

PHREEQC soil reactions

Cation ExchangeAqueous reactionsMineral denudation

CO2 dissolution

DayCent-Chem Model Processes

Stream Flow

PHREEQC stream reactions

Aqueous reactionsMineral denudation

CO2 degassing

LEACHING

Atmospheric DepositionCations and Anions

UPTAKE SOM DECOMP.MINERALIZATIONNITRIF./DENITRIF.

LITTERFALL

TRANSLOCATION Snowpack

CO2

N2ONOx

CO2

CO2

Atmospheric CO2

Soil Organic C,N,P,S

INFILTRATION

DOC, Cations, Anions, CEC

Aquifer

BASEFLOW

RUNOFF

SUBLIMATION

ET

ANC, pH, BC, Cl, Al, SO42-

NO3-

NH4+

streamflow

DayCent-Chem Data Flow

KEYH2O + species

H2O only

aquifer

solution 1

solution 2

solution n

solution n+1

solution n+2

soln.pqi

soln.selPHREEQC

phreeqc.dat

soil layer 0

soil layer 1

soil layer n-1

snowpack

yes melt sublimation

ETwater vapor loss

norain?

atmospheric deposition

aqueous species + exchanger

aqueous species only

runoff

solution 1

solution 2

solution n

solution n+1

solution n+2

dry

Labile C in surface litter

Labile C in Organic Soil Layer

Mineral Soil

Stream DOC

DayCent-Chem organic C leaching

Soil DOC

l = leaching intensity:f(soil water flow)* f(soil texture)

r = release intensity:DOCReleaseFraction * total Q / baseflow

r

l

PHREEQC(pH/Redox/Equilibrium/Carbon)

• Speciation program to calculate saturation indices and distribution of aqueous species

• Multi-phase system equilibrium with gas phases (i.e. CO2, O2), minerals, aqueous species, exchange sites.

• Ion exchange (Gaines-Thomas convention)• Surface complexation (generalized two-layer, explicit

diffuse layer, or non-electrostatic model)• Distributed with several data bases of reactions and

equilibrium coefficients, enthalpy of reaction (∆H)*.

* “careful selection of aqueous species and thermodynamic data is left to the user”

Century C-cycle

Century N-cycle

DayCent-Chem Inputs/Outputs

Inputs:• daily precipitation &

min./max. air temperatures

• precipitation concentrations (NADP)

• dry:wet ratio or dry dep amounts

• soil properties: texture, Ksat, CEC

Outputs:• daily stream outflow

and chemistry• daily soil chemistry by

soil layer• SOM composition• NPP/Biomass• ET/Sublimation• NOx, N2O emissions

DayCent-Chem Processes

Does:• speciation • mineral weathering• CO2, O2 dissolution• cation exchange

(permanent charge)• plant/microbial uptake

of NH4+, NO3

-, P, S• pH computed as

charge balance• elution

Model development:• sulfate adsorption /

pH dependent charge• plant/microbial uptake

of base cations• organic acids• O3 effects on

production (?)

John Fielder

DayCent Publications• Del Grosso, S.J., W.J. Parton, A.R. Mosier, D.S. Ojima, and M.D. Hartman. 2000.  Interaction

of Soil Carbon Sequestration and N2O Flux with Different Land Use Practices.  Pp. 303-311 in: J.van Ham et al. eds. Non-CO2 Greenhouse Gasses: Scientific Understanding, Control, and Implementation.  Kluwer Academic Publishers. Netherlands.

• Del Grosso, S.J., W.J. Parton, A.R. Mosier, M.D. Hartman, J. Brenner, D.S. Ojima, and D.S. Schimel. 2001. Simulated interaction of carbon dynamics and nitrogen trace gas fluxes using the DAYCENT model. Pages 303-332 In: M.J. Shaffer, L. Ma and S. Hansen (eds.) Modeling Carbon and Nitrogen Dynamics for Soil Management. Lewis Publishers. Boca Raton, Florida.

• Del Grosso, S.J., W.J. Parton, A.R. Mosier, M.D. Hartman, C.A. Keough, G.A. Peterson, D.S. Ojima, D.S. Schimel. 2001. Simulated effects of land use, soil texture, and precipitation on N gas emissions using DAYCENT. Pages 413-431 In: Follett, R.F., Hatfield, J.L. (eds.), Nitrogen in the Environment: Sources, Problems, and Management, Elsevier Science Publishers, The Netherlands.

• Eitzinger, J., W.J. Parton, and M. Hartman. 2000. Improvement and validation of a daily soil temperature submodel for freezing/thawing periods. Soil Science 165:525-534.

• Kelly, R.H., W.J. Parton, M.D. Hartman, L.K. Stretch, D.S. Ojima, and D.S. Schimel. 2000. Intra-annual and interannual variability of ecosystem processes in shortgrass steppe. Journal of Geophysical Research. 105:D15:20093-20100.

• Parton, W.J., A. Haxeltine, P. Thornton, R. Anne, and M. Hartman. 1996. Ecosystem sensitivity to land-surface models and leaf area index. Global and Planetary Change. 13:89-98.

• Parton, W.J., Hartman, M., Ojima, D., and David Schimel. 1998. DAYCENT and its land surface submodel: description and testing. Global and Planetary Change. 19:35-48.

• Parton, W.J., E.A. Holland, S.J. Del Grosso, M.D. Hartman, R.E. Martin, A.R. Mosier,D.S. Ojima and D.S. Schimel. 2001. Generalized model for NOx and N2O emissions from soils. Journal of Geophysical Research 106:17403-17419.

Niwot Ridge Daily Discharge

0.0

0.5

1.0

1.5

2.0

2.5

3.0

1989 1990 1991 1992 1993 1994 1995 1996 1997

cm/day

discharge simulated discharge measured

1/31/2006

R2 = 0.49

Annual VWM stream nitrate concentrationssimulated vs. Niwot Ridge observed

0

5

10

15

20

25

30

35

1989 1990 1991 1992 1993 1994 1995 1996

ueq/L

NO3-(ueq/L)

NO3(obs, ueq/L)

Niwot Daily Stream [NO3-]

0

10

20

30

40

1990 1991 1992 1993 1994 1995 1996 1997

ueq/L

NO3- NO3- (ueq/L) obs.

Annual VWM stream base cation concentrationssimulated vs. Niwot Ridge observed

0

25

50

75

100

125

1989 1990 1991 1992 1993 1994 1995 1996

ueq/L

BC (ueq/L)

BC(obs, ueq/L)

Niwot Daily Stream [Base Cations]

0

50

100

150

200

250

1990 1991 1992 1993 1994 1995 1996 1997

ueq/L

BC (ueq/L) BC (ueq/L) obs.

Niwot Daily Stream [ANC]

0

20

40

60

80

100

1990 1991 1992 1993 1994 1995 1996 1997

ueq/L

ANC(ueq/L) ANC (ueq/L) obs.

snowmelt winter

Snowmelt: ANC modelled too high

Winter: ANC modeled too low