498
Multiscale Hydrologic Remote Sensing: Perspectives and Applications
(Mississippi, Columbia, Colorado, Mackenzie, Zambezi, St. Lawrence, and Yukon)
are selected for comparing monthly TWSC estimated by the water balance approach
to GRACE. The results are presented in Figures 20.8 and 20.9. Figure 20.8 shows
the comparison of two TWSC estimates in the Mississippi River basin, where daily
discharge data from 2004 to the end of 2009 (with 1-year missing data around 2005–
2006) were provided by the USGS. All the nine GRACE datasets (including, respectively, three data processing centers and three smoothed radii) are plotted together,
0
–100
–300
–200
300
200
100
0
–50
–100
150
50
100
0
–50
–100
100
50
0
–40
–20
–80
–60
100
80
60
40
20
0
–50
–150
–100
150
50
100
0
–60
–40
–20
–80
–100
80
40
20
60
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
Amazon
Amur
Chang-Jiang
Congo
Lena
Mackenzie
TWSA (mm/month)
TWSA (mm/month)
TWSA (mm/month)
TWSA (mm/month)
TWSA (mm/month)
TWSA (mm/month)
Year
Year
Year
Year
Year
Year
(b)
FIGURE 20.7  (Continued) (b) Same as (a), but for the comparison of 2002–2007 monthly
time series of TWSA between model simulation (black) and GRACE (red).