# The Spatiotemporal Variability of Temperature and Precipitation Over the Upper Indus Basin:
## 3 Results
### Station-averaged Precipitation Trends
WRF was significantly correlated with TRMM and gauge stations (\(p<0.05\)) in all seasons except spring, where WRF was positively, but not significantly correlated with the station data. However, trend analyses for WRF, TRMM, and gauge stations located in d02 did not show any statistically significant trends except the summer season, where station data showed a statistically significant trend. Moreover, the annual TRMM showed a statistically significant trend. When WRF and TRMM data were interpolated at the twenty-three gauge locations in d03 and compared, WRF still overpredicted total annual precipitation compared with TRMM (15%) and gauge data (23%) (right column, Figure 2). In addition, the results showed that the winter season had more bias (39%) and the summer season has less bias (\(-10\%\)) to the stations' data in the inner domain (Table 3). Moreover, WRF was significantly correlated with TRMM and gauge stations (\(p<0.05\)) in all seasons except spring, where WRF was positively, but not significantly correlated with the station and TRMM data. However, trend analyses for WRF, TRMM, and gauge stations located in d03 did not show any statistically significant trends except the summer season, where station data showed a statistically significant trend. Moreover, the annual TRMM showed a statistically significant trend. The station-wise comparison of PBIAS (Table 4) also showed that most of the precipitation simulations were largely improved from d01 to d03 at all stations. Besham Qila is located at the lowest elevation, and it had a low PBIAS value (\(-13\%\)) in the d03; the increase of the resolution did not make any significant difference in the bias value. However, the highest elevated station was Khunjerab, where the precipitation simulations were improved from d01 (bias 350%) to d03 (bias 251%), but this station also had one of the largest biases. Among five high-elevation stations (Khunjerab, Ziarat, Ushkore, Yasin, and Karimabad, Karimabad, Ushkore, and Khujerab stations had the largest bias in d03. Low-elevation stations showed overall smaller biases. Among four low-elevation stations (Besham Qila, Daggar, Kandia, and Phulra), only Kandia showed a high bias (239%), whereas the other three had smaller biases (less than 20%). \begin{table}
\begin{tabular}{c c c c c} \hline \hline  & **d01** & **d02** & **d03** \\ \hline \multirow{3}{*}{Winter (DJF)} & RMSE (mm) btw WRF and Station (WRF and TRMM) & 214 (235) & 81 (101) & 53 (69) \\  & PBIAS (\%) btw WRF and Station (WRF and TRMM) & 206 (282) & 73 (116) & 39 (74) \\  & Pearson Correlation coefficient (\(r\)) btw WRF and Station (WRF and TRMM) & 0.67 (0.69) & 0.7(0.53) & 0.59 (0.55) \\ \hline \multirow{3}{*}{Spring (MAM)} & RMSE (mm) btw WRF and Station (WRF and TRMM) & 169 (169) & 89 (77) & 78 (67) \\  & PBIAS (\%) btw WRF and Station (WRF and TRMM) & 119 (112) & 55 (50) & 38 (34) \\  & Pearson Correlation coefficient (\(r\)) btw WRF and Station (WRF and TRMM) & 0.08 (0.41) & 0.34 (0.58) & 0.22 (0.44) \\ \hline \multirow{3}{*}{Summer (JJA)} & RMSE (mm) btw WRF and Station (WRF and TRMM) & 91 (72) & 42 (59) & 36 (62) \\  & PBIAS (\%) btw WRF and Station (WRF and TRMM) & 70(21) & 3 (\(-\)26) & \(-\)10 (\(-\)36) \\  & Pearson Correlation coefficient (\(r\)) btw WRF and Station (WRF and TRMM) & 0.51 (0.39) & 0.67 (0.63) & 0.7 (0.75) \\ \hline \multirow{3}{*}{Autumn (SON)} & RMSE (mm) btw WRF and Station (WRF and TRMM) & 95 (90) & 39 (39) & 25 (29) \\  & PBIAS (\%) btw WRF and Station (WRF and TRMM) & 138 (117) & 47(34) & 23 (12) \\  & Pearson Correlation coefficient (\(r\)) btw WRF and Station (WRF and TRMM) & 0.79 (0.67) & 0.82 (0.64) & 0.69 (0.65) \\ \hline \multirow{3}{*}{Annual} & RMSE (mm) btw WRF and Station (WRF and TRMM) & 525 (497) & 185 (160) & 111 (91) \\  & PBIAS (\%) btw WRF and Station (WRF and TRMM) & 132 (115) & 45 (35) & 23 (15) \\ \cline{1-1}  & Pearson Correlation coefficient (\(r\)) btw WRF and Station (WRF and TRMM) & 0.66 (0.52) & 0.74 (0.63) & 0.67 (0.59) \\ \hline \hline \end{tabular}
\end{table}