Transcript Document

DayCent-Chem
Overview
NOx
SO2
Melannie Hartman
NREL
CANS Project Meeting
Feb. 15-17, 2006
Sylvan Dale Ranch
Loveland, CO
John Fielder
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
CENTURY
CENTURY
DayCent
version 4
version 5
version 4
monthly
FORTRAN
Parton, Ojima,
Schimel 1980s
monthly, C++
Keough
Del Grosso
Parton
2001-present
DayCent
version 4.5
daily
daily
FORTRAN/C
FORTRAN/C
Hillinski
1998
Parton, Ojima,
Hartman 1994
DayCent
2001
PHREEQC
version 5
version 2.7, C
daily, C++
DayCentChem
daily, C++
Hartman, Baron,
2003-present
http://www.nrel.colostate.edu/projects/century5/
DayCent-Chem Model Processes
Atmospheric Deposition
Cations and Anions
Atmospheric CO2
SUBLIMATION
Snowpack
TRANSLOCATION
CO2
N2O
NOx
LITTERFALL
UPTAKE
Soil Organic
C,N,P,S
ET INFILTRATION
RUNOFF
NO3NH4+
SOM DECOMP.
MINERALIZATION
NITRIF./DENITRIF.
PHREEQC soil reactions
Cation Exchange
Aqueous reactions
Mineral denudation
CO2 dissolution
CO2
DOC, Cations, Anions, CEC
ANC, pH, BC, Cl, Al, SO42-
LEACHING
PHREEQC stream reactions
Aquifer
Aqueous reactions
Mineral denudation
CO2 degassing
BASEFLOW
Stream Flow
CO2
DayCent-Chem Data Flow
atmospheric
deposition
dry
rain?
yes
no
melt
ET
soil layer 0
soil layer 1
snowpack
sublimation
water vapor loss
soln.pqi
solution 1
solution 2
solution n
solution n+1
solution n+2
soil layer n-1
soln.sel
aquifer
runoff
streamflow
solution 1
solution 2
solution n
solution n+1
solution n+2
KEY
H2O + species
H2O only
phreeqc.dat
aqueous species only
aqueous species + exchanger
PHREEQC
DayCent-Chem organic C leaching
Labile C in surface litter
l = leaching intensity:
Labile C in
Organic Soil Layer
f(soil water flow)
* f(soil texture)
l
r
Soil DOC
Mineral Soil
Stream DOC
r = release intensity:
DOCReleaseFraction
* total Q / baseflow
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
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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
3.0
discharge simulated
discharge measured
2.5
1/31/2006
R2 = 0.49
cm/day
2.0
1.5
1.0
0.5
0.0
1989
1990
1991
1992
1993
1994
1995
1996
1997
Annual VWM stream nitrate concentrations
simulated vs. Niwot Ridge observed
35
30
ueq/L
25
20
15
10
NO3-(ueq/L)
NO3(obs, ueq/L)
5
0
1989
1990
1991
1992
1993
1994
1995
1
Niwot Daily Stream [NO3-]
40
NO3-
NO3- (ueq/L) obs.
ueq/L
30
20
10
0
1990
1991
1992
1993
1994
1995
1996
1997
Annual VWM stream base cation concentrations
simulated vs. Niwot Ridge observed
125
100
ueq/L
75
50
BC (ueq/L)
BC(obs, ueq/L)
25
0
1989
1990
1991
1992
1993
1994
1995
1996
Niwot Daily Stream [Base Cations]
250
BC (ueq/L)
BC (ueq/L) obs.
200
ueq/L
150
100
50
0
1990
1991
1992
1993
1994
1995
1996
1997
Niwot Daily Stream [ANC]
100
ANC(ueq/L)
ANC (ueq/L) obs.
80
ueq/L
60
40
20
snowmelt
0
1990
1991
1992
1993
winter
1994
Snowmelt: ANC modelled too high
Winter: ANC modeled too low
1995
1996
1997