499
Validation for Terrestrial Water Storage Variations
with their average denoted by black circles. As seen, two independent estimates of
monthly TWSC in the Mississippi basin show remarkable agreement in the timing of
seasonal march; also, both of them have a similar amplitude of about 50 mm/month.
Figure 20.9 plots similar comparisons of two TWSC estimates over the Columbia,
Colorado, Mackenzie, Yukon, St. Lawrence, and Zambezi River basins. The GRACE
TWSC data, averaged from the nine datasets (three data centers and three smoothing
radii), are plotted in Figure 20.9, where it clearly shows contrasting magnitudes of TWSC
among six selected basins. Based on this plot, a reasonable match in the seasonal variations between two TWSC estimates can be observed for all the basins examined, but
0
–50
–100
150
50
100
0
–50
–150
–100
150
50
100
0
–20
–40
–80
–60
80
60
40
20
100
0
–50
–100
150
50
100
0
–50
–200
–150
–100
150
50
100
0
–100
–300
–200
200
100
300
2002 2003 2004 2005 2006 2007
2002 2003 2004 2005 2006 2007
2002 2003 2004 2005 2006 2007
2002 2003 2004 2005 2006 2007
2002 2003 2004 2005 2006 2007
2002 2003 2004 2005 2006 2007
SIM
OBS
SIM
OBS
SIM
OBS
SIM
OBS
SIM
OBS
SIM
OBS
Mississippi
Murray
Ob
Volga
Yenisey
Zambezi
TWSA (mm/month)
TWSA (mm/month)
TWSA (mm/month)
TWSA (mm/month)
TWSA (mm/month)
TWSA (mm/month)
Year
Year
Year
Year
Year
Year
FIGURE 20.7  (Continued)