measuring and modeling transpiration, or what the flux is hydrology? cheas workshop
DESCRIPTION
Measuring and Modeling Transpiration, or What the Flux is Hydrology? ChEAS Workshop. Scott Mackay UW-Madison. Outline. (A) Basic Hydrologic Concepts A.1 Water Resources and Global Terrestrial Ecosystems A.2 Hydrologic budgets and conservation - PowerPoint PPT PresentationTRANSCRIPT
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Measuring and Modeling Transpiration,or What the Flux is Hydrology?
ChEAS Workshop
Scott Mackay
UW-Madison
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Outline
(A) Basic Hydrologic ConceptsA.1 Water Resources and Global Terrestrial EcosystemsA.2 Hydrologic budgets and conservationA.3 Evapotranspiration as a residual: the traditional hydrologic
approach
(B) TranspirationB.1 Direct measurements of transpirationB.2 Indirect measurements of transpirationB.3 Sapflux instrumentation and flux measurements in N. Wisconsin
(C) Water Flux ModelingC.4 Groundwater / surface water interactionsC.2 Incorporating spatial variation in water fluxesC.3 Incorporating physiologyC.4 Results from N. Wisconsin
(D) Future Directions?
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
• Suggested question:– How does landscape fragmentation affect transpiration
and carbon flux rates?
• Your mission:– Develop a 1 (2 max) page micro proposal that
addresses the above question or one of your choosing;
– Your proposal should state questions or hypotheses, objectives, how you would conduct the work, and what the anticipated results would be.
Future Directions?
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Outline
(A) Basic Hydrologic ConceptsA.1 Water Resources and Global Terrestrial EcosystemsA.2 Hydrologic budgets and conservationA.3 Evapotranspiration as a residual: the traditional hydrologic
approach
(B) TranspirationB.1 Direct measurements of transpirationB.2 Indirect measurements of transpirationB.3 Sapflux instrumentation and flux measurements in N. Wisconsin
(C) Water Flux ModelingC.4 Groundwater / surface water interactionsC.2 Incorporating spatial variation in water fluxesC.3 Incorporating physiologyC.4 Results from N. Wisconsin
(D) Future Directions?
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Water and Global Vegetation
Precipitation (mm)
500 4500
Deserts
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Outline
(A) Basic Hydrologic ConceptsA.1 Water Resources and Global Terrestrial EcosystemsA.2 Hydrologic budgets and conservationA.3 Evapotranspiration as a residual: the traditional hydrologic
approach
(B) TranspirationB.1 Direct measurements of transpirationB.2 Indirect measurements of transpirationB.3 Sapflux instrumentation and flux measurements in N. Wisconsin
(C) Water Flux ModelingC.4 Groundwater / surface water interactionsC.2 Incorporating spatial variation in water fluxesC.3 Incorporating physiologyC.4 Results from N. Wisconsin
(D) Future Directions?
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
a – evaporation, non-vegetation
b – evapotranspiration
c – lateral transport
d – precipitation
e – runoff
f – ground water recharge
Hydrologic Cycle
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Streamflow Discharge
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
tantTtq
Groundwater Flow
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Sand and Gravel AquiferPrice County
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Outline
(A) Basic Hydrologic ConceptsA.1 Water Resources and Global Terrestrial EcosystemsA.2 Hydrologic budgets and conservationA.3 Evapotranspiration as a residual: the traditional hydrologic
approach
(B) TranspirationB.1 Direct measurements of transpirationB.2 Indirect measurements of transpirationB.3 Sapflux instrumentation and flux measurements in N. Wisconsin
(C) Water Flux ModelingC.4 Groundwater / surface water interactionsC.2 Incorporating spatial variation in water fluxesC.3 Incorporating physiologyC.4 Results from N. Wisconsin
(D) Future Directions?
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
First
Stream Orders
Stream
Stream junction
Divide
Watershed Boundary
NestedWatershed
Second
Third
Hillslope
WatershedOutlet
Evapotranspiration as a Residual
P + GIN - (Q + E + GOUT) = 0
E = P - Q
AssumesGIN = GOUT
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Hillslope Profile (or Catena)
Evapotranspiration
Precipitation
Runoff
Streamflow
Infiltration
Drainage
Throughfalland stemflow
Groundwater flow
Hillslope Hydrology
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Outline
(A) Basic Hydrologic ConceptsA.1 Water Resources and Global Terrestrial EcosystemsA.2 Hydrologic budgets and conservationA.3 Evapotranspiration as a residual: the traditional hydrologic
approach
(B) TranspirationB.1 Direct measurements of transpirationB.2 Indirect measurements of transpirationB.3 Sapflux instrumentation and flux measurements in N. Wisconsin
(C) Water Flux ModelingC.4 Groundwater / surface water interactionsC.2 Incorporating spatial variation in water fluxesC.3 Incorporating physiologyC.4 Results from N. Wisconsin
(D) Future Directions?
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
1) leaf level gas exchange
a) direct measurement
b) interrupts ambient environment
c) large number of samples needed to scale up
Direct Transpiration Measurements
Pearcy et al. (1989); Schulze et al. (1982)
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
2) tree level xylem sap flow
a) large number of measurements
b) does not interrupt ambient environment
c) requires appropriate scaling in time and space
Direct Transpiration Measurements
Cermak and Kucera (1973);Granier (1987);Schulze and Fichtner (1988)
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
3) lysimeters
a) most accurate method
b) large disturbance to soil environment
c) difficult to measure large trees
d) difficult to field replicate
Direct Transpiration Measurements
van Bevel and Meyers (1962);Fritschen et al. (1973)
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Direct Transpiration Measurements
4) micrometeorological techniques
a) direct ecosystem level measurement
b) requires appropriate site conditions
c) can not separate ecosystem components directly
Campbell and Unsworth (1979);Kaimal (1979);Wyngaard (1981)
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Outline
(A) Basic Hydrologic ConceptsA.1 Water Resources and Global Terrestrial EcosystemsA.2 Hydrologic budgets and conservationA.3 Evapotranspiration as a residual: the traditional hydrologic
approach
(B) TranspirationB.1 Direct measurements of transpirationB.2 Indirect measurements of transpirationB.3 Sapflux instrumentation and flux measurements in N. Wisconsin
(C) Water Flux ModelingC.4 Groundwater / surface water interactionsC.2 Incorporating spatial variation in water fluxesC.3 Incorporating physiologyC.4 Results from N. Wisconsin
(D) Future Directions?
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Indirect Evapotranspiration Estimation
1. Temperature-Baseda. Cannot resolve time intervals less than monthlyb. Ignore processes
2. Energy Balancea. Simpleb. Relies on differences between uncertain quantitiesc. Unreliable for large vapor pressure gradients
3. Mass Transfera. Uses reliable micrometeorological measurementsb. Data collection difficult for multiple measurement sites
4. Combination Methodsa. Combines benefits of energy balance and mass transferb. Data intensive
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Thornthwaite (1949)Temperature-Based
a
I
tdE
10
6.1
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Indirect Evapotranspiration Estimation
1. Temperature-Baseda. Cannot resolve time intervals less than monthlyb. Ignore processes
2. Energy Balancea. Simpleb. Relies on differences between uncertain quantitiesc. Unreliable for large vapor pressure gradients
3. Mass Transfera. Uses reliable micrometeorological measurementsb. Data collection difficult for multiple measurement sites
4. Combination Methodsa. Combines benefits of energy balance and mass transferb. Data intensive
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Energy Balance Method
B = 0.1 (tropical oceans), 0.4 to 0.8 (temperate forests), 10.0 (deserts)
as
asa
ee
TTPc
LE
HB
622.0
EBLEBH w
B
GRE
w
n
1
w
n GHRE
Rn
G
H LE
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Indirect Evapotranspiration Estimation
1. Temperature-Baseda. Cannot resolve time intervals less than monthlyb. Ignore processes
2. Energy Balancea. Simpleb. Relies on differences between uncertain quantitiesc. Unreliable for large vapor pressure gradients
3. Mass Transfera. Uses reliable micrometeorological measurementsb. Data collection difficult for multiple measurement sites
4. Combination Methodsa. Combines benefits of energy balance and mass transferb. Data intensive
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
constant2
OHaT
e
aa eT Sate VPD
(Ideal Gas Law)
Mass Transfer
aaSatOH
a eTeP
E 2
622.0
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Frictional Drag
Eddy Currents
Z
M
M = momentum
HLE
H = sensible heatLE = latent heat of evaporation
HLE
HLE
HLEVapor
PressureGradient
TemperatureGradient
Wind Speed
Mass Transfer: Vertical Transport
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
EvKE 2
0
2
ln
622.0
2
2
z
zzPD
DK
dOH
a
M
OHE
Mass Transfer: Vertical Transport
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Indirect Evapotranspiration Estimation
1. Temperature-Baseda. Cannot resolve time intervals less than monthlyb. Ignore processes
2. Energy Balancea. Simpleb. Relies on differences between uncertain quantitiesc. Unreliable for large vapor pressure gradients
3. Mass Transfera. Uses reliable micrometeorological measurementsb. Data collection difficult for multiple measurement sites
4. Combination Methodsa. Combines benefits of energy balance and mass transferb. Data intensive
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
aaSat eTeE
OH
aaSatOHEn eTevKRE
2
2
Combination Formula (Penman, 1948)
Energy Mass TransferVertical Transport
2
0
2
ln
622.0
2
2
z
zzPD
DK
dOH
a
M
OHE
w
n GHRE
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
OH
aaSatOHEn eTevKRE
2
2
Penman-Monteith (Monteith,1965)
2
0
2
ln
622.0
2
2
z
zzPD
DK
dOH
a
M
OHE
aaSatE eTevKE
c
aOH
aaSataaanC
g
g
eTegcRE
12
2
0
2
ln
1
z
zz
v
rg
da
a
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Priestley and Taylor (1972)
OH
nTPTP
RE
2
asoilvw
assatpaS RR
eTecE
])([
Deardorff (1978); Maufouf and Noilhan (1991)
- works best for low VPD;
- crude for low canopy conductance (<20mm/s)
- sensitive to stability; -soil resistance not easyto calculate;
- numerous variants areavailable
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Outline
(A) Basic Hydrologic ConceptsA.1 Water Resources and Global Terrestrial EcosystemsA.2 Hydrologic budgets and conservationA.3 Evapotranspiration as a residual: the traditional hydrologic
approach
(B) TranspirationB.1 Direct measurements of transpirationB.2 Indirect measurements of transpirationB.3 Sapflux instrumentation and flux measurements in N. Wisconsin
(C) Water Flux ModelingC.4 Groundwater / surface water interactionsC.2 Incorporating spatial variation in water fluxesC.3 Incorporating physiologyC.4 Results from N. Wisconsin
(D) Future Directions?
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Types of Tree Level Xylem Sap Flow
Xylem flow velocity with heat pulses V=D/T Hard to determine true distances due to wall friction, anastomising
flow paths and other problems
Measurement of xylem sap mass flow (Cermak and Kucera-type sensors)
1) Null balance method maintains a constant pre-selected temperature (4 C) between temperature measurement points
a) power requirements minimal because power is proportional to flowb) little empiricismc) can not determine within tree flow paths
2) Constant heating method (Granier-type sensors)
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Granier-Type Sap Flux Measurements
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
231.1M6
S 10119
T
TTJ
Granier-Type Sap Flux Measurements
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Granier-Type Sap Flux Measurements
1) Appropriate thermal protection (Ewers and Oren 2000)a) minimize thermal gradients b) do not overinsulate
2) Sapwood estimation (Waring, et al. 1982. Whitehead et al. 1984, Ewers et al. 1999, Oren et al. 1999, Schafer et al. 2000)a) use stem cores or cross sectionsb) computer tomography
3) Spatial scaling within trees (Phillips et al. 1996, Ewers and Oren 2000, Oren et al. 1999, Clearwater et al. 1999, Lu et al. 2000, Ewers et al. 2002, James et al. 2002)a) need to measure both circumferential and radial trendsb) appropriate use of tree allometric relations
4) Environmental measurements
5) Time lags (Kostner et al. 1992, Martin et al. 1997, Phillips et al. 1997, Ewers and Oren 2000)
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Granier-Type Sap Flux Measurements
1) Appropriate thermal protection (Ewers and Oren 2000)a) minimize thermal gradients b) do not overinsulate
2) Sapwood estimation (Waring, et al. 1982. Whitehead et al. 1984, Ewers et al. 1999, Oren et al. 1999, Schafer et al. 2000)a) use stem cores or cross sectionsb) computer tomography
3) Spatial scaling within trees (Phillips et al. 1996, Ewers and Oren 2000, Oren et al. 1999, Clearwater et al. 1999, Lu et al. 2000, Ewers et al. 2002, James et al. 2002)a) need to measure both circumferential and radial trendsb) appropriate use of tree allometric relations
4) Environmental measurements
5) Time lags (Kostner et al. 1992, Martin et al. 1997, Phillips et al. 1997, Ewers and Oren 2000)
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Inner extent of sapwood
Sapwood Estimation
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Granier-Type Sap Flux Measurements
1) Appropriate thermal protection (Ewers and Oren 2000)a) minimize thermal gradients b) do not overinsulate
2) Sapwood estimation (Waring, et al. 1982. Whitehead et al. 1984, Ewers et al. 1999, Oren et al. 1999, Schafer et al. 2000)a) use stem cores or cross sectionsb) computer tomography
3) Spatial scaling within trees (Phillips et al. 1996, Ewers and Oren 2000, Oren et al. 1999, Clearwater et al. 1999, Lu et al. 2000, Ewers et al. 2002, James et al. 2002)a) need to measure both circumferential and radial trendsb) appropriate use of tree allometric relations
4) Environmental measurements
5) Time lags (Kostner et al. 1992, Martin et al. 1997, Phillips et al. 1997, Ewers and Oren 2000)
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
3
1
3
1
ii
iSii
S
W
JW
J
Circumferential Trends
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
G
SSC AA
JE
Allometric Relations
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Granier-Type Sap Flux Measurements
1) Appropriate thermal protection (Ewers and Oren 2000)a) minimize thermal gradients b) do not overinsulate
2) Sapwood estimation (Waring, et al. 1982. Whitehead et al. 1984, Ewers et al. 1999, Oren et al. 1999, Schafer et al. 2000)a) use stem cores or cross sectionsb) computer tomography
3) Spatial scaling within trees (Phillips et al. 1996, Ewers and Oren 2000, Oren et al. 1999, Clearwater et al. 1999, Lu et al. 2000, Ewers et al. 2002, James et al. 2002)a) need to measure both circumferential and radial trendsb) appropriate use of tree allometric relations
4) Environmental measurements
5) Time lags (Kostner et al. 1992, Martin et al. 1997, Phillips et al. 1997, Ewers and Oren 2000)
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Canopy Environmental Measurements
Environmental measurements (VPD)
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Granier-Type Sap Flux Measurements
1) Appropriate thermal protection (Ewers and Oren 2000)a) minimize thermal gradients b) do not overinsulate
2) Sapwood estimation (Waring, et al. 1982. Whitehead et al. 1984, Ewers et al. 1999, Oren et al. 1999, Schafer et al. 2000)a) use stem cores or cross sectionsb) computer tomography
3) Spatial scaling within trees (Phillips et al. 1996, Ewers and Oren 2000, Oren et al. 1999, Clearwater et al. 1999, Lu et al. 2000, Ewers et al. 2002, James et al. 2002)a) need to measure both circumferential and radial trendsb) appropriate use of tree allometric relations
4) Environmental measurements
5) Time lags (Kostner et al. 1992, Martin et al. 1997, Phillips et al. 1997, Ewers and Oren 2000)
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Diurnal Time Lags and Daily Fluxes
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Canopy Transpiration – N. Wisconsin
Notes: All species show exponential EC
rise to a maximum with respect to vapor pressure deficit;
Stomatal control exhibits similar function across species;
Maximum stomatal conductance varies 2-3 fold among species
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Outline
(A) Basic Hydrologic ConceptsA.1 Water Resources and Global Terrestrial EcosystemsA.2 Hydrologic budgets and conservationA.3 Evapotranspiration as a residual: the traditional hydrologic
approach
(B) TranspirationB.1 Direct measurements of transpirationB.2 Indirect measurements of transpirationB.3 Sapflux instrumentation and flux measurements in N. Wisconsin
(C) Water Flux ModelingC.4 Groundwater / surface water interactionsC.2 Incorporating spatial variation in water fluxesC.3 Incorporating physiologyC.4 Results from N. Wisconsin
(D) Future Directions?
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
tantTtq
Recall: Groundwater Flow
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
fazz /))tan/ln(( area
a )tan/ln(
Topography-Based Groundwater-Surface Water Interactions
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Groundwater Flow
Samanta and Mackay, 2002, WRR in press
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Outline
(A) Basic Hydrologic ConceptsA.1 Water Resources and Global Terrestrial EcosystemsA.2 Hydrologic budgets and conservationA.3 Evapotranspiration as a residual: the traditional hydrologic
approach
(B) TranspirationB.1 Direct measurements of transpirationB.2 Indirect measurements of transpirationB.3 Sapflux instrumentation and flux measurements in N. Wisconsin
(C) Water Flux ModelingC.4 Groundwater / surface water interactionsC.2 Incorporating spatial variation in water fluxesC.3 Incorporating physiologyC.4 Results from N. Wisconsin
(D) Future Directions?
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Effect of reduced stomatal regulation of leaf water potential is to lower Bowen ratios, increase pre-dawn water potentials and reduce water use efficiency
Soil or VPD ControlledTranspiration?
Mackay, 2001
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Outline
(A) Basic Hydrologic ConceptsA.1 Water Resources and Global Terrestrial EcosystemsA.2 Hydrologic budgets and conservationA.3 Evapotranspiration as a residual: the traditional hydrologic
approach
(B) TranspirationB.1 Direct measurements of transpirationB.2 Indirect measurements of transpirationB.3 Sapflux instrumentation and flux measurements in N. Wisconsin
(C) Water Flux ModelingC.4 Groundwater / surface water interactionsC.2 Incorporating spatial variation in water fluxesC.3 Incorporating physiologyC.4 Results from N. Wisconsin
(D) Future Directions?
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Physiology of Water FluxLeaf Water Potential
Pre-Dawn: Stomata Closed Midday: Stomata Open
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
ghΨΨDKG wLSLS
DmGG lnSrefS SrefS 6.0lndd GDGm
Monteith, 1995; Sperry et al., 1998; Oren et al., 1999; Ewers et al., 2000
Hydraulic Limits to Transpiration
0
20
40
60
80
100
120
140
160
180
0 1 2
lnD [ln(kPa)]
GS
(mm
ol
m-2
s-1) bDmGs ln
0
20
40
60
80
100
120
140
160
180
0 1 2
lnD [ln(kPa)]
GS
(mm
ol
m-2
s-1) bDmGs ln
0
10
20
30
40
50
60
70
80
90
100
0 50 100 150 200
GSref (mmol m-2 s-1)
-dGS
/ dl nDS
[mm
ol
m-2
s-1l n
(kP
a)-1
]
SrefGb
DG
m S
lndd
0
10
20
30
40
50
60
70
80
90
100
0 50 100 150 200
GSref (mmol m-2 s-1)
-dGS
/ dl nDS
[mm
ol
m-2
s-1l n
(kP
a)-1
]
SrefGb
DG
m S
lndd
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
f f f min321SmaxS Q g = g
DgG 1SmaxSref
D
Dgm
lnd
ddˆ Smax
DmQGG lnˆ, minSrefS
Replacing Boundary Line Analysis with Modeling
Model gSmax, , Qmin with automated parameter evaluation
Qmin
Jarvis (1976)
Mackay et al (2002)Advances in Water Resources
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Universal Relationship
0
0.4
0.8
1.2
0 0.5 1 1.5 2
G Sref (mm s-1)
-dGS
/dlnD
[m
m s
-1 ln
(kP
a)-1
]
red pine
aspen
sugar maple
alder
cedar
m ~ -0.6 GSref y = 0.601x - 0.022
R2 = 0.96
0
0.4
0.8
1.2
0 0.5 1 1.5 2
G Sref (mm s-1)
-dGS/d
lnD
[m
ms
-1 ln
(kP
a)-1
]
Stomata are regulatingleaf water potential
Mackay et al (2002) - Advances in Water Resources
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Outline
(A) Basic Hydrologic ConceptsA.1 Water Resources and Global Terrestrial EcosystemsA.2 Hydrologic budgets and conservationA.3 Evapotranspiration as a residual: the traditional hydrologic
approach
(B) TranspirationB.1 Direct measurements of transpirationB.2 Indirect measurements of transpirationB.3 Sapflux instrumentation and flux measurements in N. Wisconsin
(C) Water Flux ModelingC.4 Groundwater / surface water interactionsC.2 Incorporating spatial variation in water fluxesC.3 Incorporating physiologyC.4 Results from N. Wisconsin
(D) Future Directions?
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Mackay et al., 2002 GCB
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Effect of Spatial Aggregation
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Effect of Taxonomic Aggregation
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
Outline
(A) Basic Hydrologic ConceptsA.1 Water Resources and Global Terrestrial EcosystemsA.2 Hydrologic budgets and conservationA.3 Evapotranspiration as a residual: the traditional hydrologic
approach
(B) TranspirationB.1 Direct measurements of transpirationB.2 Indirect measurements of transpirationB.3 Sapflux instrumentation and flux measurements in N. Wisconsin
(C) Water Flux ModelingC.4 Groundwater / surface water interactionsC.2 Incorporating spatial variation in water fluxesC.3 Incorporating physiologyC.4 Results from N. Wisconsin
(D) Future Directions?
Ecosystem Hydrology Modeling Group email: [email protected]://ra.forest.wisc.edu/ehmg
ChEAS WorkshopKemp StationAugust 20, 2002
• Suggested question:– How does landscape fragmentation affect transpiration
and carbon flux rates?
• Your mission:– Develop a 1 (2 max) page micro proposal that
addresses the above question or one of your choosing;
– Your proposal should state questions or hypotheses, objectives, how you would conduct the work, and what the anticipated results would be.
Future Directions?