Statistical results for monthly TRMM precipitation and gauge precipitation during 1998–2013 are shown in Table 5. The mean precipitation, RMSEs and BIAS of monthly precipitation are consistent with those of daily precipitation. Meanwhile, PCCs show an obvious increase ranging from 0.86 to 0.98, and present a good linear relation between monthly TRMM precipitation and gauge precipitation, especially at basin scale. Moreover, Figure 5 shows the relation between monthly gauge precipitation and TRMM precipitation from 1998 to 2013 at station and basin scales. It is seen that monthly TRMM precipitation is highly consistent with the monthly gauge precipitation with R2 ranging between 0.74 and 0.96, which verifies that there is a good linear relation between monthly TRMM precipitation and gauge precipitation. Therefore, although areal TRMM precipitation overestimates the precipitation with a BIAS of 0.2 over the basin, there is a good linear relation between monthly TRMM precipitation and gauge precipitation.
Table 5

Summary of statistical results in comparison of monthly TRMM precipitation and gauge precipitation at station and basin scales during 1998–2013

Gauge No./Basin5529455299560185610656109561165620256223Basin
Mean (mm)
Gauge 40.72 39.53 45.67 52.83 52.92 56.42 62.59 35.31 47.18
Original TRMM 36.52 48.44 43.58 62.76 69.32 59.80 73.71 62.84 56.77
Corrected TRMM 30.68 40.69 36.61 52.72 58.23 50.24 61.91 52.79 47.69
RMSE (mm)
Original TRMM 20.86 20.19 13.64 26.36 32.47 17.72 29.76 40.51 15.98
Corrected TRMM 24.67 13.94 18.78 20.10 21.46 18.64 22.59 29.12 9.66
Bias
Original TRMM −0.10 0.23 −0.05 0.19 0.31 0.06 0.18 0.78 0.20
Corrected TRMM −0.25 0.03 −0.20 0.00 0.10 −0.11 −0.01 0.49 0.01
PCC
Gauge & original TRMM/gauge & corrected TRMM 0.92 0.95 0.96 0.93 0.94 0.96 0.93 0.86 0.98
Gauge No./Basin5529455299560185610656109561165620256223Basin
Mean (mm)
Gauge 40.72 39.53 45.67 52.83 52.92 56.42 62.59 35.31 47.18
Original TRMM 36.52 48.44 43.58 62.76 69.32 59.80 73.71 62.84 56.77
Corrected TRMM 30.68 40.69 36.61 52.72 58.23 50.24 61.91 52.79 47.69
RMSE (mm)
Original TRMM 20.86 20.19 13.64 26.36 32.47 17.72 29.76 40.51 15.98
Corrected TRMM 24.67 13.94 18.78 20.10 21.46 18.64 22.59 29.12 9.66
Bias
Original TRMM −0.10 0.23 −0.05 0.19 0.31 0.06 0.18 0.78 0.20
Corrected TRMM −0.25 0.03 −0.20 0.00 0.10 −0.11 −0.01 0.49 0.01
PCC
Gauge & original TRMM/gauge & corrected TRMM 0.92 0.95 0.96 0.93 0.94 0.96 0.93 0.86 0.98
Figure 5

Scatter plots of monthly precipitation from rain gauges and TRMM precipitation at station and basin scales during 1998–2013. Solid lines and their equations are obtained from the LRM between monthly TRMM precipitation and gauge precipitation with offset parameter a = 0.

Figure 5

Scatter plots of monthly precipitation from rain gauges and TRMM precipitation at station and basin scales during 1998–2013. Solid lines and their equations are obtained from the LRM between monthly TRMM precipitation and gauge precipitation with offset parameter a = 0.

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