Figure 2 shows the time series of the monthly-accumulated rainfall in millimeters of Thailand Rain Gauges data average over the 40 grid boxes with the GPCC data over the 10-year period (1993 to 2002). Figure 3 shows the TRMM 3B42, the TRMM 3B43 and Thailand Gauge data for the period 1998 to 2002. The bias and the root mean square difference (RMSD) between the monthly gauges data and other data sets are summarized in the table 1.
Not surprisingly, the GPCC is close to Thailand gauge estimates. On the other hand, the TRMM 3B42 is much higher than gauges, especially during the raining season (June to September). Since 3B43 is a merged gauge and satellite product, the bias is in between GPCC and 3B42.