# The Spatiotemporal Variability of Temperature and Precipitation Over the Upper Indus Basin:
## 4 Discussion and Conclusions  
The WRF model was applied to simulate the spatiotemporal variability of precipitation and temperature over the Indus Basin from 2000 through 2015 using boundary conditions derived from the CFSR reanalysis dataset. We found that most of the precipitation trends in WRF, TRMM, and station precipitation at gauge locations were not statistically significant, which was consistent with [PERSON] et al. [48], [PERSON] et al. [49], and [PERSON] et al. [23]. The critical aspect was how the simulated precipitation amount and bias changed as resolution increased. The precipitation simulations were significantly improved from d01 (36 km) to d03 (4 km). The annual PBIAS between WRF and stations' data was decreased from d01 (132%) to d03 (23%). These results seemed broadly consistent with the previous studies [14; 15; 23; 50; 51], which also showed a positive influence of increasing resolution on precipitation over complex regions. Moreover, the WRF was significantly correlated with TRMM and station data in most of the seasons (except spring season) in all domains. WRF was able to capture the precipitation trends in most of the seasons, but tended to overestimate precipitation in all domains, which may reflect an underestimation of precipitation by the observed datasets as discussed earlier. Many researchers have revealed that the existing observation  
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Station**} & \multirow{2}{*}{ \begin{tabular}{c} **Station** \\ **Elev.** \\ **(m)** \\ **d01** \\ \end{tabular}  } & \multirow{2}{*}{ \begin{tabular}{c} **WRF** \\ **Elev.** \\ **(m) in** \\ **d02** \\ \end{tabular}  } & \multirow{2}{*}{ \begin{tabular}{c} **WRF** \\ **Elev.** \\ **(m) in** \\ **d03** \\ \end{tabular}  } & \multirow{2}{*}{ \begin{tabular}{c} **WRF** \\ **Elev.** \\ **(d01)** \\ \end{tabular}  } & \multirow{2}{*}{ \begin{tabular}{c} **Diff.** \\ **(d02)** \\ **(d03)** \\ \end{tabular}  } & \multirow{2}{*}{ \begin{tabular}{c} **Diff.** \\ **T2** (°C) in d01** \\ \end{tabular}  } & \multirow{2}{*}{ \begin{tabular}{c} **Interpolated** \\ **T2** (°C) in d02** \\ \end{tabular}  } & \multirow{2}{*}{ \begin{tabular}{c} **Interpolated** \\ **T2** (°C) in d03** \\ \end{tabular}  } \\  & & & & & & & & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} \\ \hline \multicolumn{1}{c}{\multirow{6}{*}{\ \begin{tabular}{c} Astore \\ Bunji \\ Chillas \\ Chitali \\ Chitali \\ Gligit \\ Gupi \\ Gligit \\ Gupi \\ Gligit \\ Gupi \\ Gligit \\ Gupi \\ Glardia \\ Skardi \\ Khunjerab \\ Khunjerab \\ Rama \\ Ratta \\ Ratta \\ Ratta \\ Ratta \\ \end{tabular}  } &
\begin{tabular}{c} 3824 & 3705 & 3500 \\ 3824 & 1634 & \(-\)1537 & \(-\)1332 \\ 37454 & 2638 & 1634 & \(-\)2082 & \(-\)1266 \\ 30979 & 1932 & 1397 & \(-\)1847 & \(-\)682 \\ 30979 & 1276 & 2507 & \(-\)  
dataset network including TRMM 3B42V7 underestimates precipitation amounts by 66% to 300% over the UIB [52; 53; 54]. The gauges in the UIB in Pakistan suffer from undercatch for winter precipitation, especially snowfall ([PERSON] et al. [15]), which could cause a significant amount of wet bias in this season. However, precipitation occurs in the form of rain in spring and summer seasons over this region, which the rain gauges measure more accurately. This contributed to less discrepancy between WRF precipitation and station observations in the summer season. However, the WRF simulations for temperature were much better than those of precipitation. The mean bias was noticeably reduced with the increasing resolution. The WRF model showed an underestimation of 2 m air temperature in all domains and seasons, which was consistent with prior studies [23] over this region. The higher resolution simulations show a significantly improved representation of the climatic variables. Therefore, the spatial grid spacing resolution of the inner domain (d03) is high enough to capture the orographic effects in this area.