## 4 Results
### Precipitation Analysis in the Varzob River Basin
During the period from 1991 to 2018, a significant trend of decreasing precipitation in June and July was registered, while from 1964 to 2018, a significant trend in decreasing precipitation in April was registered. During the period from 1960 to 1990, at Hushyori station, a significantly downward trend presented in November. From 1960 to 2018, a significant increase in precipitation was recorded in February and June, while a significant decrease in precipitation was only shown in December from 1991 to 2018. Table 5 presents the results of the annual precipitation trend, slope, and change points in the three meteorological stations in the VRB. In the Anzob station, a significant negative trend in the annual precipitation was found in the upstream region during the periods of 1991-2018 and 1960-2018, while a non-significant positive trend was indicated during the period 1960-1990. According to the conducted analysis, in the Maykhura station (midstream region), precipitation during three historical times periods indicated a significant decreasing trend. Our result for the annual precipitation analysis presented a significant decreasing trend during the period of 1991-2018 at the Hushyori station, while from 1960 to 2018, the annual precipitation was found to have a slightly increasing trend in this region. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Month**} & \multicolumn{3}{c}{**Anzob Precipitation (mm)**} & \multicolumn{3}{c}{**Maykhura Precipitation (mm)**} & \multicolumn{3}{c}{**Hushyori Precipitation (mm)**} \\ \cline{2-10}  & **1960–1990** & **1991–2018** & **1960–2018** & **1964–1990** & **1991–2018** & **1964–2018** & **1960–1990** & **1991–2018** & **1960–2018** \\ \hline January & 2.567 *** & \(-\)0.375 & 2.426 ** & \(-\)0.521 & \(-\)0.356 & \(-\)1.075 & 0.799 & \(-\)0.593 & 0.131 \\ February & 0.034 & \(-\)0.356 & 2.152 ** & \(-\)0.772 & 0.356 & 0.9 & \(-\)0.646 & 0.454 & 1.713 * \\ March & \(-\)0.085 & \(-\)1.087 & \(-\)0.19 & \(-\)0.208 & \(-\)1.246 & \(-\)1.35 & 0.17 & \(-\)0.099 & \(-\)0.137 \\ April & \(-\)0.884 & \(-\)0.771 & \(-\)3.714 *** & \(-\)1.981 ** & \(-\)0.514 & \(-\)3.035 *** & \(-\)1.428 & \(-\)0.771 & \(-\)1.04 \\ May & \(-\)0.323 & \(-\)1.127 & \(-\)4.362 ** & \(-\)0.208 & \(-\)0.04 & \(-\)1.416 & \(-\)1.292 & \(-\)0.257 & \(-\)0.497 \\ June & 0.952 & \(-\)2.47 ** & \(-\)1.236 & 0.709 & \(-\)1.681 * & 0.653 & 0.102 & \(-\)1.126 & 1.524 * \\ July & 0.425 & \(-\)2.312 ** & \(-\)0.935 & \(-\)0.521 & \(-\)2.018 * & \(-\)0.842 & 0.493 & \(-\)0.633 & 0.916 \\ August & \(-\)0.102 & \(-\)1.146 & \(-\)0.726 & 0.668 & \(-\)0.514 & \(-\)0.036 & 0.935 & \(-\)0.817 & 1.06 \\ September & \(-\)1.122 & \(-\)0.929 & \(-\)0.903 & \(-\)0.73 & \(-\)0.929 & \(-\)0.443 & 0.732 & \(-\)0.139 & 0.269 \\ October & 0.629 & 1.344 & \(-\)1.014 & \(-\)0.459 & 0.376 & \(-\)1.176 & 0.935 & 0.711 & \(-\)0.301 \\ November & \(-\)0.306 & \(-\)0.356 & \(-\)0.02 & \(-\)0.083 & 0.356 & 1.198 & \(-\)1.751 * & 0.573 & 0.517 \\ December & 2.465 ** & \(-\)1.995 ** & \(-\)0.098 & 1.251 & \(-\)1.186 & \(-\)0.298 & 0.918 & \(-\)1.561 * & \(-\)0.216 \\ \hline \hline \end{tabular}  
* The significance levels tested are **
* for \(p<0.001\), *
* for \(p<0.01\),
* for \(p<0.05\), NS for \(p\geq 0.1\).  
\end{table} 
Table 4: The seasonal precipitation trends applying the original Mann–Kendall test in upstream, midstream, and downstream meteorological stations in the Varzob River Basin in Tajikistan during three different periods (1960–1990, 1991–2018, and 1960–2018). Figure 7 depicts the rapid shifts in yearly precipitation in the Varzob River Basin during the three historical periods. At the Maykhura and Hishyori stations, the yearly precipitation experienced dramatic shifts in the first historical time period in 1969, but not at the Anzob station between 1960 and 1990. The dramatic change occurred in the second historical period in 1999 (in Anzob station), 1994 (in Maykhura station), and 2004 (in Hushyori station).