Zong-Liang Yang Guo-Yue Niu, Enrique Rosero, Xiaoyan Jiang, and Lindsey Gulden http://www.geo.utexas.edu/climate/ Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin Prepared for NCAR Noah Meeting July 25-26, 2007 Noah Development at UT- Noah Development at UT- Austin Austin
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Zong-Liang Yang Guo-Yue Niu, Enrique Rosero, Xiaoyan Jiang, and Lindsey Gulden
Noah Development at UT-Austin. Zong-Liang Yang Guo-Yue Niu, Enrique Rosero, Xiaoyan Jiang, and Lindsey Gulden http://www.geo.utexas.edu/climate/ Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin Prepared for NCAR Noah Meeting - PowerPoint PPT Presentation
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Zong-Liang Yang
Guo-Yue Niu, Enrique Rosero, Xiaoyan Jiang, and Lindsey Gulden
http://www.geo.utexas.edu/climate/Department of Geological Sciences,
Jackson School of Geosciences,
The University of Texas at Austin
Prepared for NCAR Noah Meeting
July 25-26, 2007
Noah Development at UT-Noah Development at UT-AustinAustin
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Towards a physically complete model
Wat
er
Space
Time
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Improving Hydrological Representation in the Community Noah Land Surface Model for Intraseasonal to Interannual Prediction Studies
PI: Zong-Liang YangCo-PIs: Guo-Yue Niu, Fei Chen, David GochisCollaborator: Ken Mitchell
Funded by NOAA CPPA
Summer 2007 – Summer 2010
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New Developments include:
A 3-Layer physically-based snow model
A simple TOPMODEL-based runoff model
A simple groundwater model
Modifications on frozen soil permeability
Evaluation against snow and runoff data over grassland
A interactive vegetation canopy model (LAI is a predicted variable)
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Model Development at UT-Austin(http://www.geo.utexas.edu/climate/Research/
publications.htm)• Improved TOPMODEL runoff (Yang and Niu, 2003, GPC;
Niu and Yang, 2003, GPC; Niu et al., 2005, JGR)• Improved frozen soil scheme (Niu and Yang, 2006,
JHM)• Multi-layer snow (Yang and Niu, 2003, GPC)• Snow and vegetation canopy interaction (Niu and Yang,
2004, JGR)• Snow cover fraction (Niu and Yang, 2007, JGR)• Global unconfined aquifer/groundwater component (Niu
et al., 2007, JGR)• Comparison of stochastic and physically-based subgrid
snow cover fraction for snow assimilation (Su et al., 2007; Yang et al., 2007)
These physical parameterizations are expected to work for both climate and weather models.
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Snow layer number and depthThe total no. of layers can be up to 3 layers depending on total snow depth:
Melting Energy is too low – T12 is the forcing of snow/soil system
Α = αv + (1-(1-fb )*fveg )*fsnow (αsnow –αv)where fb is the buried fraction of the canopy
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Snow Skin Temperature
How T12 performs compared to observations (A France grassland dataset) ?
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Snow Skin Temperature
Newton-Raphson Iterative Method
Based on energy balance - Sg + L(Tg) + H(Tg) + LE(Tg) + G(Tg) = 0.
Iteration of all the fluxes and stability correction.
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Snow Skin Temperature
How Tg performs in VISA (A France grassland dataset) ?
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Available Energy for Snowmelt
Compare snowmelt energy between VISA and Noah-3L
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A Simple Groundwater Model
Water storage in an unconfined aquifer:
Recharge Rate:
)1(bot
bota zzK
Gravitational Drainage
sba RQ
dt
dW ya SWz /
Upward Flow under capillary forces
Buffer Zone
bot
botbota zz
zzKQ
)(
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A Simple TOPMODEL Model
Surface Runoff : Rs = P fsat
fsat = Fmax e – C f zwt (1 – ffrz) + ffrz
p = precipitation
zwt = the depth to water table
f = the runoff decay parameter that determines recession curve
Subsurface Runoff : Rsb= Rsb,maxe –f zwt
Rsb,max = the maximum subsurface runoff when the grid-mean water table is zero. It should be related to lateral hydraulic conductivity of an aquifer and local slopes (e-λ) .
SIMTOP parameters:
Two calibration parameters Rsb,max (~10mm/day) and f (1.0~2.0)
Two topographic parameters Fmax (~0.37) and C (~0.6)
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Runoff – Sleepers River
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Runoff – Sleepers River
RUNOFF1 + RUNOFF2
RUNOFF1
RUNOFF2
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Water table depth – Sleepers River
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Soil Moisture – Sleepers River
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Soil Moisture – Champion, Illinois
f = 1.0 f = 1.5
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Soil Moisture – Frozen Soil Impacts
SH2O(4)
SH2O(3)
SH2O(2)
SH20(1)In default Noah:
Freezing = Drying
Niu and Yang (2006):
Fractional frozen area is used to modify soil hydraulic properties.
K(i) = (1 – ffrz) K(θ)
SH20 -> SMC
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Stomatal conductance is linearly related to photosynthesis:
(The “Ball-Berry-Collatz” parameterization)
Photosynthesis is controlled by three limitations(The Farquahar-Berry model):