Hydrological Models and GRACE
Satellite Observations in Cold
Regions
by
Kenneth R. Snelgrove1
Sitotaw Yirdaw-Zeleke2
Workshop Presentation
IP3 in Cold Regions
Saskatoon, Oct 19-20, 2006
1 Faculty
of Engineering and Applied Science, Memorial
University of Newfoundland
2 Department
of Civil Engineering, University of Manitoba
Overview
WatFLOW Development
¾Adding groundwater for Atmospheric Models
(CLASS)
¾Coupling improved CLASS Model with
Groundwater Model
GRACE Gravity Variation
¾Assess changes in moisture storage over
Western Canada for Drought study
¾Hydrological Model Calibration and Validation
Prairie Hydrology
Assiniboine Delta Aquifer
Distribution of Surficial Deposits of the Assiniboine Delta Aquifer
L.H. Frost and F.W. Render, 2002
CLASS
Second Generation Land Surface Scheme
RADIATIVE
EXCHANGE
SENSIBLE
EXCHANGE
MOISTURE
EXCHANGE
ra
IR up
Evaporation
Aerodynamic
resistance
( ra )
α veg
Interception
Tc Canopy
Transpiration
Leaves
LAI
Stomata
Temperature and humidity
rs
Wind
Leaf Drip
Fraction vegetation cover &
LAI
Fn ( temperature & season)
IR up
Snow
( light sensitivity
changes rs )
IR down
Stems
SAI
α soil
Infiltration
Surface
Runoff
Fn ( soil wetness)
Tg
Surface Soil
Temperature
Upper layer
wetness
Upper soil layer
Full soil column
Lower Soil
Temperature
Tgb
Root Distribution
Fn ( vegetation type)
Full column wetness
Subsurface Runoff
CLASS/WatCLASS
Coupling CLASS to
Groundwater
∇
Coupling CLASS to
Groundwater
MM5
CLASS
MODFLOW
Coupling CLASS to
Groundwater
Models
Observation
Distributed Water Balance
AL
AL
AL
AL
AL
AL
AL
=AB
AL
AL
Hydrologic P-E vs. no snow simulated streamflow
40
35
30
25
mm of water
Atmosphere
(A)
20
15
10
5
0
-5
P-E
Land Surface
(L)
QL
QL
Channel
Network
(C)
QL
QL
-10
Oct-95
Nov-95
Dec-95
Jan-96
Outflow = QL, Runoff =
RL
QL
Outflow QB,Runoff RB=QB/AB
Groundwater flow (G)
Feb-96
Mar-96
Apr-96
Date
May-96
Jun-96
Jul-96
Aug-96
Sep-96
GRACE Terrestrial Moisture Changes
Introduction
Twin GRACE Satellites
Launch on 2002 March 17
Flying approximately 220 km apart
Altitude of 400-500 km
m2
Newton’s Law of Gravitation
m1m2
F =k 2
r
r
r
m2
m1
GRACE Primary Mission
Gravity Model
•Develop geoid from averages over 5 year life
•Monthly variations related to surface moisture changes
Creation of Earth Geopotential Map
Time-variable geopotential δG(t) solution of Laplace Equation
N
n
δG (t ) = ∑ ∑ (δCnm (t ) cos mλ + δS nm (t ) sin mλ )Pnm (cos θ )
n =1 m = 0
where:
l is the latitude
q is the longitude
m & n are harmonic degree and order
P is Legendre’s polynomial
Monthly Difference Result
April 2002
April 2003
mm of Equivalent water thickness
Water Balance Methods
Atmospheric Moisture Budget:
<P – E>a = – <∂q/∂t> – <∇ •Q>
Where: (P-E) = difference between precipitation and evapotranspiration,
q = the vertically-integrated vapour mass or precipitable water,
∇ •Q = the moisture flux divergence,
Q = qV ; V is wind speed
Hydrologic Water Budget:
<P – E>h = <R> + <∂S/∂t >
where: S = surface water storage
R = basin runoff
Grace Result := <∂S/∂t > + <∂q/∂t>
Water Balance Methods
AL
AL
AL
AL
AL
AL
AL
AL
AL
q – Atmos. Storage
Atmosphere
(A)
∇•Q - Atmos. Runoff
(P-E)a = (P-E)h
Land Surface
(L)
S - Basin Storage
Channel
Network
(C)
R - Basin Runoff
q - Atmospheric Storage
Data Source: CMC 4x Daily Analysis
∇·Q - Atmospheric Runoff
Data Source: CMC 4x Daily Analysis
Alternate ∇•Q - Calculation
via Green’s Theorem
Atmospheric (P-E) For Water Years 2002-2004
(Mackenzie River Basin)
50
40
30
20
10
0
-10
-20
Line Integral
Divergence
-30
Apr-02
Jul-02
Oct-02
Jan-03
Apr-03
Jul-03
Time (Months)
Oct-03
Jan-04
Apr-04
Jul-04
Atmospheric and Hydrologic Basin Change in Storage
For Water Years 2002-2004 (Mackenzie River Basin)
60
Hydrologic
40
Atmospheric
Atmospheric - mean(E-P)
20
0
-20
-40
-60
-80
-100
Apr-02
Jul-02
Oct-02
Jan-03
Apr-03
Time
Jul-03
Oct-03
Jan-04
Apr-04
Jul-04
Atmospheric, Hydrologic and GRACE based Change in
Storage relative to mean Geopotential For Water Years
2002-2004 (Mackenzie River Basin)
100
0
-100
-200
-300
-400
Hydrologic
-500
Apr-02
Jul-02
Oct-02
Atmospheric - mean(E-P)
Jan-03
Apr-03
Jul-03
Time (Months)
Atmospheric
Oct-03
GRACE
Jan-04
Apr-04
Jul-04