## 2 Study Area, Data, and Methodology
### Methodology
#### 2.3.2 Precipitation Indices  
Table A1 in Appendix A shows the list of precipitation indices used in this study. These precipitation indices were adapted from the joint CCI/WCRP/JCOMM Expert Team Expert Team on Climate Change Detection and Indices (ETCDDI) ([[https://www.wcrp-climate.org/etccdi-members](https://www.wcrp-climate.org/etccdi-members)]([https://www.wcrp-climate.org/etccdi-members](https://www.wcrp-climate.org/etccdi-members)), accessed on 15 March 2022) and CCI Expert Team on Sector-Specific Climate Indices (ET-SCI) ([[https://climpact-sci.org/about/project/](https://climpact-sci.org/about/project/)]([https://climpact-sci.org/about/project/](https://climpact-sci.org/about/project/)), accessed on 15 March 2022). Daily IMERG precipitation estimates were used to compute these indices at IMERG grid locations, and daily GP precipitation values were used to compute the same at GP locations. Annual Total Precipitation (PRCPTOT), Wet Days (R1), and Daily Intensity (SDII)  
We assigned a daily precipitation threshold of 1 mm to define a wet and dry day. R1 was computed by counting the number of wet days in a year. PRCPTOT was computed \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**SN**} & **Station** & \multirow{2}{*}{**Name**} & \multirow{2}{*}{**Data Gap \%**} & **Lon** & **Lat** & **Elevation** & **Annual Precipitation** \\  & **Index** & & & **(Degree)** & **(Degree)** & **(m)** & **(Mean \(\pm\) SD) (mm)** \\ \hline
1 & 208 & Sandepani & 0.8 & 80.98 & 28.66 & 159 & \(1965.5\pm 456.9\) \\
2 & 304 & Guthi Chaur & 2.1 & 82.33 & 29.23 & 2727 & \(1073.5\pm 188.2\) \\
3 & 306 & Gam Shree Nagar & 7.6 & 82.15 & 29.55 & 2113 & \(854.8\pm 271.1\) \\
4 & 308 & Nagma & 0.8 & 81.91 & 29.20 & 2017 & \(851.3\pm 169.6\) \\
5 & 324 & Rudu (Narakot) & 0.4 & 81.99 & 29.33 & 2364 & \(768.1\pm 97.4\) \\
6 & 414 & Baijapur & 5.4 & 81.90 & 28.02 & 150 & \(977.5\pm 452.1\) \\
7 & 510 & Koilabas & 0.0 & 82.53 & 27.69 & 200 & \(1497.2\pm 260.2\) \\
8 & 511 & Salyan Bazar & 0.0 & 82.14 & 28.38 & 1557 & \(956.7\pm 182.4\) \\
9 & 615 & Bobang & 6.5 & 83.08 & 28.40 & 1722 & \(2238\pm 405\) \\
10 & 619 & Ghorepani & 0.0 & 83.70 & 28.40 & 2987 & \(2599.8\pm 373.7\) \\
11 & 630 & Sirkon & 6.3 & 83.63 & 28.13 & 731 & \(2052.7\pm 388.9\) \\
12 & 701 & Ridi & 0.2 & 83.44 & 27.94 & 494 & \(1212.6\pm 286.1\) \\
13 & 723 & Bhagwanpur & 3.8 & 82.79 & 27.67 & 148 & \(1524.5\pm 421.4\) \\
14 & 806 & Larke Samdo & 5.0 & 84.62 & 28.67 & 3650 & \(658.8\pm 199.7\) \\
15 & 813 & Bhadaure Deurali & 0.0 & 83.82 & 28.27 & 1617 & \(4356.1\pm 122.4\) \\
16 & 1006 & Gumthang & 4.7 & 85.86 & 27.87 & 1885 & \(3320.6\pm 1058\) \\
17 & 1016 & Samathang & 6.8 & 85.60 & 27.94 & 2574 & \(3260.9\pm 858.1\) \\
18 & 1054 & Thamachit & 0.0 & 85.30 & 28.18 & 1770 & \(891.6\pm 608.3\) \\
19 & 1058 & Tarke Ghyang & 5.3 & 85.55 & 28.00 & 2596 & \(3420.9\pm 564.4\) \\
20 & 1063 & Thokarpa & 7.0 & 85.78 & 27.69 & 1565 & \(1634.4\pm 335.3\) \\
21 & 1075 & Lele & 0.0 & 85.35 & 27.58 & 1590 & \(1612.9\pm 351.6\) \\
22 & 1081 & Jitpurbedhi & 0.8 & 85.29 & 27.78 & 1409 & \(1833.5\pm 218.5\) \\
23 & 1216 & Siraha & 5.8 & 86.21 & 26.66 & 63 & \(1377.8\pm 376.8\) \\
24 & 1219 & Salleri & 3.0 & 86.59 & 27.51 & 2383 & \(1644.6\pm 359.5\) \\
25 & 1317 & Chepuwa & 6.7 & 87.41 & 27.75 & 2039 & \(2403.6\pm 560.5\) \\ \hline \hline \end{tabular}
\end{table} 
Table 2: List of selected ground-based precipitation stations. The mean and standard deviation (SD) of annual precipitation is computed from precipitation data from 2001 to 2020.  
by adding all the daily precipitation values during those wet days. SDII is a simple ratio between PRCPTOT and R1, which informs the average daily precipitation value during wet days over a year. Percentile-Based Precipitation Indices (95 th and 99 th Percentile)  
Similar to the PRCPTOT, these percentile-based precipitation indices (r95p and r99p) were computed by summing the daily precipitation value exceeding a threshold.