Applied Hydrology (2011/7/6)

Modeling of land surface processes

Kenji TanakaKenji TanakaWater Resources Research Center,

DPRI, Kyoto Universityy ytanaka.kenji.6u@kyoto-u.ac.jp

Land Surface Process“Land surface processes are those associated with thethose associated with the exchange of water and energy between the land surface andbetween the land surface and the atmosphere and are, therefore, integral components of hydrologic and atmospheric sciences.”(by Bill Crosson (NASA MSFC))(by Bill Crosson (NASA MSFC))

Hydrological CycleHydrological Cyclefrom GEWEX home page

LSS (L d S f S h )LSS (Land Surface Scheme)

In general, Land Surface Scheme (LSS) are designed to solve for the interaction of radiation, energy, momentum,

d ( t ) b t th f d thand mass (water vapor) between the surface and the overlying atmosphere.

LSS also have to deal with the large heterogeneity of the earth's surface and this fact creates great complexity in LSS.

In attempt to provide appropriate lower boundaryIn attempt to provide appropriate lower boundary conditions to the atmosphere, several LSS have been developed and coupled into global-scale and regional-scale atmospheric models in the past decade.

i d

i it tiCanopy energy fluxes

wind

precipitation

Interception b

y gySensible Latent

Top of

Radiative Fluxes

Sh Lby canopycanopy Shortwave Longwave

TranspirationEnergy budget

Th hf ll S f ff

Bare soil energy fluxesSensible Latent

Radiation budget

Throughfall

Infiltration

Surface runoffGroundheat flux

W t b d tDiffusion/drainageHeat exchange

Water budget

Baseflow

Radiation budgetRadiation budget• All surfaces receive short-wave radiation during g

daylight and exchange long-wave radiation continuously with the atmosphere. y p

short-wave radiation (sun) < 4 μmlong-wave radiation (earth) > 4 μmg ( ) μ

• Rn = (1-α)Sd + Ld – LuRn (1 α)Sd Ld Lu

• Sd = Svb + Svd + Snb + Snd• Sd = Svb + Svd + Snb + SndVisible/Near Infrared (0.72μm)Beam/DiffuseBeam/Diffuse

Energy budgetEnergy budget• Rn is partitioned into fluxes of sensible, latent, p , ,

and gound heat.

• This partitioning is strongly dependent on both the land cover characteristics (landuse) and itsthe land cover characteristics (landuse) and its hydrological state (wet/dry).

• Why energy partitioning is important?R H λE GRn = H + λE + G

H heating lower atmosphereλE h ti iddl t hλE heating middle atmosphereG surface (time lag between RB & EB)

Surface energy balance at different landuseSurface energy balance at different landuse

paddy field forestｌEｌE

H

G

GHH

lake cityGGG

ｌEｌE

H

H

H

Water budgetWater budget• Water is exchanged between the atmosphere

and the land surface through the processes of precipitation, evaporation, and transpiration.

• Water is exchanged between the land surface d /l k th h ffand ocean/lake through runoff.

∆S P E R• ∆S = P - E - R P : precipitation(rain/snow) input from atmosphereE : water vapor flux by evaporation and transpirationE : water vapor flux by evaporation and transpirationR : runoff flux by river system and ground water system∆S : change in the surface water and soil moisture

Evapotranspiration = Evaporation + TranspirationEvapotranspiration Evaporation + Transpiration

evaporation Evapotranspiration is an interface evaporation

Interceptionwater

Between water cycle and energy cycle

Water cycle：

stomata transpiration

yRainfall reached to surface go back to atmosphere as water vapor. Evaporation is a loss term in terms of

evaporation water resources.

Energy cycle：

soil moistureTransfer the energy of vaporization to atmosphere. Energy absorbed by surface is redistributed to atmosphere.

Root zoneWater vapor from surface will condense (latent heat release) and fall down again as rainfallas rainfall.

In-situ Flux station (Lake Biwa Project)• Three sites from the Lake Biwa Project

Fluxes of radiation budget and heat budget component and related meteorological and hydrological variables can be used from these datasets.

• Two sites from the snow depth observation station

Forest Area

Paddy Field

8 km8 km8 km8 km8 km8 km8 km8 km8 km

8 km8 km8 km8 km8 km8 km8 km8 km8 km

MapFan II PUE ©IPCMapFan II PUE ©IPCMapFan II PUE ©IPCMapFan II PUE ©IPCMapFan II PUE ©IPCMapFan II PUE ©IPCMapFan II PUE ©IPCMapFan II PUE ©IPCMapFan II PUE ©IPC

Lake Surface

Flux measurement in the Paddy Field

GEWEX Continental Scale Experiments

Arvaikheer

AmdoTokyo

HUBEX

KogmaMaetoh

Sukhothai

PBL tower

Aug. 12, 2004Turbulent flux

Surface energy fluxes (5day average)

Every 30 minuteSensible heat flux (30 minutes)Every 30 minute( )

Monthly mean surface temperature over Tibetan Plateau（1998）by Dr Okuby Dr.Oku

a) Map of Thailandb) Topographic map of northern Thailand and study sites.

Result of ObservationKogMa

Result of Observation

N. Tanaka

Hydro-meteorology: H. TakizawaCanopy interceptionBy 田中延亮さん N. Tanaka

TranspirationRain

y

Discharge

Wet conditionDry condition

DischargeSap flow measurementN. Yoshifuji

Stomatal ClosureC. TantasirinS. Piman

Transpiration peak in the late dry season！Stomatal closure is open!Sap flow shows it!

y

N. TangthamSap flow shows it!Simulation also shows it!

T i tiT i ti

Numerical Simulation (by 田中克典さん)

Transpiration

Rainfall

Interception

Transpiration

Rainfall

Interception

Sap flows

Soil evaporation

Sap flows

Soil evaporationSoil evaporationSoil evaporation

average soil depth = 4 5m

Dry season

Soil surface

Dry season

Soil surface

average soil depth = 4.5m

Deeper root can get water from the deeper soil layers

Dry season

Dep

th (

m)

Bedrock

Water table

Dry season

Dep

th (

m)

Bedrock

Water table

GAME-Tropics (Sukhothai Thailand)GAME Tropics (Sukhothai Thailand)

March : No-vegetation and dried surface periodM N t ti d t ti i f ll i dMay : No-vegetation and starting rain fall period

August : Beginning of rice planting, submerged periodNovember : Before harvesting period

Energy balance at Paddy field (Sukhothai)7-year average seasonal cycle7 year average seasonal cycle

20

25

aytim

e)

By Dr.Komori

10

15

Heat balance (MJ/day

RnGLEHGw

0

5

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep Oct

Nov

Dec

H

D R i

2

ctor

B i C fDry season Rainy season

1

1.5

ratio

& C

rop

fac Bowen ratio Crop factor

50

s(%

)

0

0.5

Bowen

r

25 100W t L l TDR 15 RH

10

20

30

40

Wat

er C

onte

nts

10

15

20

er leve

l (cm

)

40

60

80

Hum

idity

&

ate

r Conte

nt (

%)Water Level TDR-15cm RH

0

Jan

Feb

Mar Ap

rMay Ju

nJu

lAu

gSe

pOct

Nov

Dec

Soi

l W

Dry season Rainy season0

5Wate

0

20

H

Soil W

at

Application to the Huaihe River Basin ChinaApplication to the Huaihe River Basin China (GEWEX/GAME/HUBEX)

• Off-line simulation using GAME-HUBEX IOP datasurface meteorological data GMS-VIS (for short-wave radiation)GMS-VIS (for short-wave radiation)

• Period : 1998/5/1-1998/8/31 (1hour interval)• Domain: E111-122 N31-36 (5min mesh）• Domain: E111 122, N31 36 (5min mesh）

• LSS : SiBUC + Paddy fileld scheme+ Farmland irrigation scheme

G iGrowingseasonwater

1995 December Many cups of “Kanpei”Make up friendship

1996 March

Make-up friendship

1996 May

199 h1997 March

1997 March1997 March

Preliminary observation in 1997 August

GAME HUBEX flux measurement at 4 landuseGAME-HUBEX flux measurement at 4 landuse

Paddy Field FarmlandPaddy Field Farmland

Forest LakeForest Lake

Padd Field FarmlandPaddy Field Farmland

Forest LakeForest

LSS (Land Surface Scheme)LSS (Land Surface Scheme)

InputSurface meteorological variables(Prec, SWdown, LWdown, Tair, Eair, Wind, Psfc, etc.)Surface parameters(V t ti t S il t LAI fl t t )(Vegetation type, Soil type, LAI, reflectance, etc.)

OutputOutputSurface energy balance components (H, λE, G, etc.)Surface water balance components (Evap Qs Qsb etc )Surface water balance components (Evap, Qs, Qsb, etc.)Surface state variables (Tsoil, SoilMois, SWE, etc.)

Land Surface ModelM l i l b d di i (P i i i Meteorological boundary condition (Precipitation, Temperature, Humidity, Radiation, Wind)

Radiation Water budgetRadiation budget

E

Evaporation

Energy budget

Temperature

Soil moistureRun0off

p

Soil moistureRun0off

LSS for what?LSS for what?

• BC of atmospheric model (energy & radiation balance, friction)

• BC of hydrological model(surface runoff, baseflow)

• IWRM(evaporation, soil moisture, IWR, snow, WQ,..)

• Analysis/Predictiontime varying parameters for past/futureseasonal variation + inter annual variation+seasonal variation + inter-annual variation+human impact

History of LSS development• Bucket scheme (1969)

A near surface layer of soil is modeled as a bucket that can be filled by

History of LSS development

A near-surface layer of soil is modeled as a bucket that can be filled by precipitation and snowmelt and emptied by evaporation and by runoff (occurs only when the bucket is full). The evaporation efficiency is a linear function of the amount of water in the bucket below some critical value.

• BATS (1986); SiB (1986); ISBA (1989)The vegetation is treated explicitly as two separate layers, scaling fromThe vegetation is treated explicitly as two separate layers, scaling from the size of real leaves up to the size of a grid element of the atmospheric model.

• PLAID (1989); MOSAIC(1992)PLAID (1989); MOSAIC(1992)The heterogeneity of vegetation cover is treated by mosaic-of tiles with each tile consisting of a single land-use. The grid averaged surface fluxes are obtained by averaging the surface fluxes over each land-use

i ht d b it f ti lweighted by its fractional area.

• SiB2 (1996)A more realistic treatment of the response of stomatal conductance to

i t l f i Gl b l d t t f t ti h l denvironmental forcing. Global data sets of vegetation phenology and associated model parameters are derived from satellite observations.

Present ? Future ?1. How the hydrological cycle in watershed will bey g y

affected due to external disturbance such asclimate change?

2. How the hydrological cycle in watershed will bey g yaffected due to the alteration of land surfacecondition such as deforestation, urbanization?

3. What kind of watershed is strong/ feasible/gadaptable/ sustainable under climate change ?

4. Human activity (flood control, irrigation, release of heat) is also an important part of energy andof heat) is also an important part of energy andwater cycle.

Need for the land surface scheme that can express the actual land surface condition and that is physically based (not black box)

Th ti ti f thThe motivation for the development of SiBUCp

• To represent various land surface condition

• Extension of urbanized areaarea

• Agricultural cropland?

W t B d ？• Water Body？

Land use for the Lake Biwa Basin

• Strategy of model developmentStrategy of model development- basic policy：physically consistent- the element which has different major processthe element which has different major process should be treated distinctly

- but not be too complicatedbut not be too complicated（awareness of application）

• Mount human activity to physical modelirrigation anthropogenic heat land use change- irrigation, anthropogenic heat, land-use change

SiBUC (land surface model)

CComponent1.Green area model2 U b d l2.Urban canopy model3.Water body model

INPUTBoundary Conditions

Zm reference height m

Tm air tempreture at Zm K result

INPUT

Culculate

em vapor pressure at Zm mb

um wind speed at Zm m/s

S↓downwward short-wave radiation

W/m2

T surface temperaturecanopy, ground, water body, roof of building, wall of building, road

Tg ground temperature green area, water body, urban

L↓downward long-wave radiation

W/m2

P precipitation m/s

M interrupted precipitationcanopy, ground, roof ofbuilding, wall of building

W soil moisture contentSurface layer, root zone, recharge zone

F ti l A P t i tiFractional Area Parameterization

S ibl h t l t t h t d t fl• Sensible heat, latent heat, and momentum fluxes are calculated separately for each landuse.

• [F]total=[F]iVi=[F]gaVga+[F]uaVua+[F]wbVwb

Land surface model (SiBUC)( )

Grid box is divided into１．Broadleaf-evergreen trees２．Broadleaf-deciduous trees３ Broadleaf and needle leaf trees

three landuse categories1. Green Area

３．Broadleaf and needle leaf trees４．Needle leaf-evergreen trees５．Needle leaf-deciduous trees６ Sh t t ti /C4 l d

2. Urban Area3. Water Body

６．Short vegetation/C4 grassland７．Broadleaf shrubs with bare soil８．Dwarf trees and shrubsy９．Farmland (non-irrigated)10. Paddy field (non-irrigated)11. Paddy field (irrigated)y ( g )12. Spring wheat (irrigated)13. Winter wheat (irrigated)14 Corn (irrigated)14. Corn (irrigated)15. Other crops (irrigated)

Green Area Model (SiB)Green Area Model (SiB)

T d l th t ti it lf d th b• To model the vegetation itself and thereby calculate the radiation, momentum, heat and water vapor transfer properties of the surface in a consistent way.

• The morphological and physiological characteristics of the vegetation are used c a acte st cs o t e egetat o a e usedto derive coefficients and resistances.

Green area model（SiB）（ ）• Prognostic variables

temperature (canopy, ground, deep soil)p ( py g p )interception water (canopy, ground)soil wetness (surface, root zone, recharge)

• Time invariant parametergeometrical parametergeometrical parameteroptical parameterphysiological parametersoil physical propertiessoil physical properties

• Time varying parameter (LAI etc.)estimate from satellite data

• Physical processesPhysical processesradiative transferinterception losssoil hydrologycanopy resistancecanopy resistancetranspirationturbulent transfer,snow, freezing/melting,… etc., g g,

Three layer soil modelThree layer soil model

• Surface layeracts as a significant source of direct evaporationacts as a s g ca t sou ce o d ect e apo at owhen the soil surface is wet

• Root zone• Root zoneThe roots are assumed to access the soil moisture from the second layermoisture from the second layer

• Recharge layeracts as a source for hydrological baseflow andacts as a source for hydrological baseflow andupward recharge of the root zone.

Physical Processes expressed in SiBy p• the reflection, transmission, absorption and emission of

direct and diffuse radiation in the visible near infrared anddirect and diffuse radiation in the visible, near infrared and thermal wavelength intervals (radiative transfer)

• the interception of rainfall and its evaporation from the leaf p psurfaces (interception loss)

• the infiltration, drainage, and storage of the residual rainfall in the soil (soil hydrology)in the soil (soil hydrology)

• the control by the photosynthetically active radiation (PAR) and the soil moisture potential over the stomataland the soil moisture potential over the stomatalfunctioning (canopy resistance)

• transfer of the soil moisture to the atmosphere through the l f f h ( )root-stem-leaf system of the vegetation (transpiration)

• the aerodynamic transfer of water vapor, sensible heat and momentum from the vegetation and soil to a referencemomentum from the vegetation and soil to a reference level within the ABL (turbulent transfer)

Turbulent transferTurbulent transfer• Vertical profile of wind speed

d dd diff i iand eddy diffusivity are calculated using different regime in each layer.regime in each layer.

Above transition layerwithin transition layerwithin canopy air spacewithin canopy air spacebelow canopy

• Resistances are calculated byResistances are calculated by integrating the inverse of eddy diffusivity along the transfer pathwaytransfer pathway.

Surface resistancesSurface resistances

• Soil surface resistance is a function of surface soil wetness（dry large）of surface soil wetness（dry large）

• Stomatal resistance of single leaf is a function of PAR flux, leaf

d fi itemperature, water vapor deficit, leaf water potential.

• Single leaf stomatal resistances are• Single leaf stomatal resistances are integrated using leaf angle distribution function to produce bulk canopy resistance.

[ ]*

1( ) p c

c c a g a c

C W r W rE e T e V V

ρλ

⎛ ⎞−= − +⎜ ⎟蒸散 [ ]* ( )c c a g a c

c b br r rγ ⎜ ⎟+⎝ ⎠蒸散

抵抗の概念を用いたバルク式

Wrc : 濡れてる面積Vc : 植物キャノピー率Vga : 緑地面積

蒸散抵抗蒸散抵抗Rc

• 気孔の開閉を支配する因子• 気孔の開閉を支配する因子– PAR強度– 葉面温度– 大気の飽差

葉水ポ シ

ストレス項として表現 : f(Σ)– 葉水ポテンシャル

気孔抵抗

OL θθξππ

∫∫∫2 )sin()(1

dLddPARr

ONf

r s

L

cc

tc θξθξκθθξπ

∫∫∫∑=2

0

2

00 ),,,(

)sin(),()(

1

ストレス項 f(Σ)( )

dLddO

NfLtc θξθθξππ

∫∫∫∑2

2)sin(),(

)(1

気孔抵抗 dLddPARr

Nfr s

cc

θξθξκ

ξ∫∫∫∑=

0

2

00 ),,,(

)(),()(

4

( ) ( ) ( , ) ( )

( )( )

a a l

h

f f T f T e f

T T T T

ψ∑ =4

40 0

( )( )( )

( )( )

( )

l hh

l h

T T T Tf T

T T T T

T T

− −=

− − 0 : ( ) 1

:h

T f T

T

=最適温度　

最高限界温度

[ ]

04

0

5

( )

( )

( ) 1 ( )

h

l

T Th

T T

f T h T

−=

−5

:

:

:

lT

h

ψ

最低限界温度

種に依存する定数

気孔が閉じ始める時の水分ポテンシャル[ ]5*

2

( , ) 1 ( )

( )

a a a a

ll

f T e h e T e

fψ ψψ

= − −

−=

1

2

:

:

ψψ

気孔が閉じ始める時の水分ポテンシャル

気孔が開き始める時の水分ポテンシャル

1 2ψ ψ−

Sensible and latent heat fluxesSensible and latent heat fluxes

Fl i ti l t• Flux is propotional to potential difference and inversely propotional to (a e se y p opot o a to (aseries of) resistance.

• Total of evaporation from il ti f fsoil, evaporation of surface

water, transpiration from canopy, evaporation ofcanopy, evaporation of intercepted water is equal to the water vapor flux from canopy air space tocanopy air space to reference height.

Prognostic equation of green area modelPrognostic equation of green area model

c EHRT

C λ−−=∂Temperature

dg

ccncc

TTCEHRT

C

EHRt

C

ωλ

λ

−−−−=∂

=∂

)(

e pe atu e

ggngd

d

dggggngg

EHRT

C

TTCEHRt

C

λ

ωλ

−−=∂∂∂

)(

ggngd t∂

⎤⎡S il W1,2,11

1

1

1

1

W

EE

QPDt

Wdc

w

s

s

∂

⎥⎦

⎤⎢⎣

⎡−−−=

∂∂

ρθSoil Wetness

[ ]

[ ]

2,3,22,12

2

1

1

W

EQQDt

Wdc

s

∂

−−=∂∂

θ

[ ]33,23

3 1QQ

Dt

W

s

−=∂∂

θ

Energy Budget4(1 )nR S L T

dS

α εσ= − ↓ + ↓ − R:net radiationH:sensible heat fluxλE:latent heat flux

n

dSR H E G

dtλ= − − −

λE:latent heat fluxG:soil heat fluxL:long wave radiationS:Short wave radiation

Alb dRn Hc+λEc α: Albedo

canopy

Rn

Tc

Hc+λEc

cc c c c

TC Rn H E

tT TT

λ∂= − −

∂∂

Rw Hw+λEw

/ 2

(1 ) ( )

w gww w w w w w

w

g w g

T TTC Ln Sn H E k

t D

T T TC S k C T T

β λ

β

−∂= + − − −

∂∂ −

+

water

Surface layer

Tw

Tg

Dw

2Kw(Tw-Tg)/Dw

(1 ) ( )/ 2

( )

g gg w w d g d

w

dd d g d

C Sn k C T Tt D

TC C T T

t

β ω

ω

= − + − −∂∂

= −∂

Root zoneTdωCd(Tg-Td)

gt∂Recharge zone

Water budget of SiB Model

c cc c

w

M EP D

t ρ∂

= − −∂

11 1 2 1

1

1 1( )

1

s d cs w

WP Q E E

t D

EW

θ ρ⎡ ⎤∂

= − − +⎢ ⎥∂ ⎣ ⎦⎡ ⎤∂

g gg g

w

M EP D

t ρ∂

= − −∂

[ ]

221 2 2 3

2

3

1

1

d c

s w

EWQ Q

t D

WQ Q

θ ρ⎡ ⎤∂

= − −⎢ ⎥∂ ⎣ ⎦∂

= −[ ]2 3 33s

Q Qt Dθ

=∂

P:precipitationcanopy

Pc Ec

Dc c t trE E E= +

W: soil moisture contentM:interrupted precipitationQ:discharge E:evaptranspiraionDgPg E

Ed1

1 2tr d c d cE E E= +

E:evaptranspiraion

Surface layerW1

groundDgPg Eg

D1Q12

Edc1

D ’ lSurface layer

Root zoneW2 D2

Q12

Q23

Edc2

1Q Kz

∂Ψ⎡ ⎤= +⎢ ⎥∂⎣ ⎦

Darcy’s low

Recharge zoneW3

D3

Q3

⎣ ⎦

Paddy field modelPaddy field model• Water depth and water temperature

are addedare added

cccc

c lEHRnt

TC −−=

∂∂

)(gwg

w

gwwwww

www

CTT

kT

C

D

TTklEHRn

t

TDC

−∂

−−−−=

∂∂

)(

)(

dgd

dd

dggw

gww

gg

TTCT

C

TTCD

TTk

t

TC

−=∂

−−=∂∂

ω

ω

• Water depth control (irrigation / drainage)

di t th i t

)( gdt∂

according to the growing stage, optimal / minimum water depthare specifiedPonding irrigationPonding irrigationInternal drainIntermittent irrigation

Irrigation scheme

Water control in farmland

Soil moisture

Days

• Basic concept is to maintain water depth / soil moisture within appropriate ranges for optimal crop growthwithin appropriate ranges for optimal crop growth

• New water layer is added to treat paddy field more accurately

• Application to wheat, corn, soy bean and rice (paddy field) etc…

Irrigation scheme

Water control in paddy field

• Basic concept is to maintain water depth / soil moisture within appropriate ranges for optimal crop growthwithin appropriate ranges for optimal crop growth

• New water layer is added to treat paddy field more accurately

• Application to wheat, corn, soy bean and rice (paddy field) etc…