## 4 Results
### Evaluation of Temporal and Spatial Dynamics
The GPCC and TRMM points marked closer to the reference point indicated that the products relatively performed better and they are suitable for the study region. The rest of the precipitation products also depicted good agreement with observed data over the study region, with notable mean error all the way. These results are in agreement with the findings of [27, 72] who reported the better performances of TRMM and GPCC products. The range of agreement is different, which could be due to a difference in region, study period and statistical metrics. Moreover, the Taylor analysis during winter precipitation indicated the better performance of CRU and TRMM products as marked closer to the reference data with relatively higher CC of around 97% and lower values of RMSD. The GPCC, APHRODITE, and CHIRPS products also showed better efficiency in terms of high CC and lower RMSD values. On the other hand, the evaluation of precipitation products during summer monsoon revealed the better performance of GPCC and TRMM products, as indicated by a higher CC of around 98% and lower RMSD values. These results are consistent with the outcomes of products evaluation during the annual time scale over the study region. The efficiency of GPCC and TRMM precipitation products during annual and summer season was found to be similar and consistent. The major influence of annual precipitation variability depends upon the summer monsoon season, as it receives the major amount of precipitation and main driver of annual hydrological cycle [73]. Overall, the performance of GPCC and TRMM products were best during the annual and summer time scale over the study region. However, CRU product shows relatively better performance during the winter monsoon period. Figure 8 shows the spatial distribution of GB and SB precipitation products against reference data in terms of spatial pattern of statistical indices (ME, RMSD and CC) over the Punjab region during the whole study periods. The results indicated that all of the GB products underestimated the precipitation amounts as compared with observed precipitation. The range of deviation was more conspicuous in northern Punjab with the dominated pattern of underestimation from north to south gradient. In the entire study period, the GPCC product exhibited best agreement, as indicated by the distribution of higher CC and lower values of ME and RMSD. However, the accuracy of GPCC product was more precise over northeast and southern part of Punjab. The inter-comparison of GB products indicated the similar pattern of underestimation, except the UDel and CPC product, which indicated the higher  
Figure 7: Statistical evaluation of (**A**) (GB) and (**B**) (SB) precipitation products against reference data by using Taylor diagram. range of underestimation over the whole study region. Both of the products showed the lowest agreement following by APHRODITE product as compared with the observed pattern of precipitation. On the other hand, the SB precipitation products showed the visible pattern of overestimation over the whole study region. However, the pattern was more conspicuous over the northern and eastern part of the study region. Moreover, all of the products showed a similar pattern of underestimation over south-west part of the study region. However, the pattern of underestimation was more noticeable in PERSIANN products over south to south west gradient as compared with observed precipitation. The statistical pattern of all the SB products pointed out the better performance of TRMM product in terms of higher CC and lower ME and RMSD values. The TRMM product outperformed the rest of the product by showing the lowest error and highest accuracy. However, the pattern of overestimation was more noticeable over the northern region of the study area. The overestimation in these areas could be related to the higher rate of evaporation.