497
Validation for Terrestrial Water Storage Variations
20.5.3    gRace twSa veRSuS coMBined land–  atMoSPheRe 
wateR Balance eStiMateS
The application of the combined land–atmosphere water balance computation in
deriving the estimate of TWSC (dS/dT in Equation 20.3) is largely limited by the
availability of observed streamflow data within the GRACE period. Most of river
discharge data provided by GRDC are only for the twentieth century, with only very
little available for the twenty-first century. Therefore, only seven large river basins
80
0
–20
–60
–80
–100
–40
60
40
20
80
0
–20
–60
–80
–40
60
40
20
0
–50
–100
100
50
60
0
–20
–60
–40
40
20
250
0
–50
–150
–200
–100
200
150
100
50
0
–50
–150
–100
150
100
50
J a n
F e b
M
a r
A
p r
M
a y
J u n
J u l
A
u g
S e p
O
c t
N
o v
D
e c
J a n
F e b
M
a r
A
p r
M
a y
J u n
J u l
A
u g
S e p
O
c t
N
o v
D
e c
J a n
F e b
M
a r
A
p r
M
a y
J u n
J u l
A
u g
S e p
O
c t
N
o v
D
e c
J a n
F e b
M
a r
A
p r
M
a y
J u n
J u l
A
u g
S e p
O
c t
N
o v
D
e c
J a n
F e b
M
a r
A
p r
M
a y
J u n
J u l
A
u g
S e p
O
c t
N
o v
D
e c
J a n
F e b
M
a r
A
p r
M
a y
J u n
J u l
A
u g
S e p
O
c t
N
o v
D
e c
OBS
SIM
OBS
SIM
OBS
SIM
OBS
SIM
OBS
SIM
OBS
SIM
Mississippi
Murray-Darling
Ob
Volga
Yenesey
Zambezi
TWSA (mm/month)
TWSA (mm/month)
TWSA (mm/month)
TWSA (mm/month)
TWSA (mm/month)
TWSA (mm/month)
Month
Month
Month
Month
Month
Month
FIGURE 20.7  (Continued)