## 4 Results
### Model Performance in Typical Rainfall Events  
#### 4.3.1 Comparison of Temporal Variation Processes  
Four typical rainfall events were chosen during the testing stage, and the variation patterns of rainfall observed by rain gauges, GPM, spatiotemporal interpolation by F-SVD, and the spatiotemporal fused data by FS-ConvLSTM were compared. The results are displayed in Figure 7.  
From Figure 7a, it is evident that, for the light rainfall events, the rainfall intensities at all moments are below 1 mm/h. All types of rainfall data accurately capture the rainfall events, but there are differences in rainfall magnitudes. The GPM overestimates the rainfall significantly at all three stations, and the data of F-SVD and FS-ConvLSTM are closer to the actual measured values, with the fused data slightly higher than the ground observations. Notably, at Pucheng station, the value of FS-ConvLSTM is larger than that of F-SVD at the time of approaching the rain peak. Figure 7b shows that for the medium rainfall event, the rainfall intensity is below 3 mm/h at all moments. All three types of data reflect the rainfall event accurately, but GPM poorly describes the rain peak present time, and the rain peak at Pucheng station is earlier than the actual measurement, while the rain peak at Dongyou station is later than the actual measurement, showing considerably more uncertainty. At most moments, GPM is higher than the actual measurement, and the data of F-SVD and FS-ConvLSTM are slightly lower than the actual measurement. For the peak of rainfall, the values of FS-ConvLSTM are closer to the measured values compared to F-SVD. Figure 7c shows that, for heavy rainfall events, the maximum rainfall intensity is around 6 mm/h.  
Figure 7: Comparison of the temporal variation process at three selected rain gauges. (**a**) Small rain; (**b**) Moderate rain; (**c**) Heavy rain; (**d**) Torrential rain.  
At Pucheng and Wufu stations, GPM appears to underestimate the rainfall, and the rainfall variation trend reflected at Pucheng station lags behind the measured data. Both the F-SVD and FS-ConvLSTM data accurately reflect the magnitudes and trends of the rainfall, but overall, FS-ConvLSTM performs better than F-SVD. Finally, Figure 7d illustrates that, for torrential rainfall events, the maximum rainfall intensity is above 15 mm/h. GPM underestimates the rainfall events, and the capture of rainfall trends at the Wufu station is also biased. There is also a slight underestimation in F-SVD for the rain peaks, and the rain peaks of FS-ConvLSTM are closer to the measured values than F-SVD.  
After analyzing the four different magnitudes of rainfall events, it can be concluded that GPM is less reliable in describing the rainfall magnitude. The data tend to overestimate rainfall for light and moderate rainfall events while underestimating rainfall for heavy and torrential rain. On the other hand, F-SVD provides a more accurate description of rainfall magnitudes and rainfall trends, despite underestimating the rainfall peaks. FS-ConvLSTM outperforms F-SVD in accurately reflecting the rainfall events, particularly in rainfall peaks, which is more evident in heavy and torrential rainfall events.