## 4 Results
### Air Temperature Analysis in the Varzob River Basin
From 1960 to 2018, the temperature in March, April, May, and September significantly increased. Table 3 shows the trend and magnitudinal analysis of the mean annual air temperature at Anzob, Maykhura, and Hushyori stations, which was carried out by [PERSON]'s slope, [PERSON]'s test, as well as the original and modified MK tests for the trends (Z) in the upstream, midstream, and downstream areas of the Varzob River Basin in Tajikistan during the three time periods. In the Anzob region, during the period from 1961 to 1990, the mean annual temperature indicated a significant upward trend, while during the periods 1991-2018 and 1961-2018, a non-significant positive trend was observed. The analysis of the mean annual temperatures in 1964-1990, 1991-2017, and 1964-2017 exhibited a significant increasing trend in the Maykhura region. In the years from 1991 to 2018, a significant increasing trend in the mean annual temperature was observed at Hushyori station. Similarly, in this region, during the period from 1960 to 2018, we observed an increasing trend for the mean annual temperature. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**Month**} & \multicolumn{3}{c}{**Anzob Average Temperature (\({}^{\circ}\)C)**} & \multicolumn{3}{c}{**Maykhura Average Temperature (\({}^{\circ}\)C)**} & \multicolumn{3}{c}{**Hushyori Average Temperature (\({}^{\circ}\)C)**} \\ \cline{2-10}  & **1961–1990** & **1991–2018** & **1961–2018** & **1964–1990** & **1991–2017** & **1964–2017** & **1960–1990** & **1991–2018** & **1960–2018** \\ \hline January & 0.429 & \(-1.7\)* & \(-1.91\)* & 1.79* & 1.043 & 2.851** & \(\cdots\) & 0.272 & 1.9* & 1.616* \\ February & \(-0.071\) & \(-1.662\)* & \(-1.107\) & \(-0.021\) & 2.003** & 2.851** & \(-0.595\) & 0.949 & 0.942 \\ March & \(-1.519\)* & 1.108 & \(-0.389\) & \(-0.271\) & 2.9** & 3.232** & \(-1.157\) & 2.69** & 2.068** \\ April & 0.839 & 1.838 * & 1.416 & 1.295 & 2.189** & 2.419** & 1.344 & 2.196** & 2.912** \\ May & 0.732 & 2.312 ** & 1.611 * & 1.419 & 2.755** & 2.493** & 0.478 & 2.492** & 2.037 \\ June & 0.357 & 2.688 ** & 1.53 & 0 & 1.816* & 0.366 & \(-0.562\) & 2.95* & 0.281 \\ July & 1.019 & 1.403 & 0.832 & 1.128 & 2.169 * & 0.105 & \(-0.46\) & 2.573** & \(-0.111\) \\ August & 1.179 & \(-0.198\) & 1.202 & 1.402 & 0.856 & 0.388 & \(-0.835\) & 1.248 & 0.347 \\ September & 2.769 ** & 0.613 & 3.519 ** & 3.298 ** & 1.711 * & 2.994** & 0.29 & 1.128 & 2.269 * \\ October & 0.786 & 0 & 2.074 ** & 0.689 & 2.045 ** & 2.143 & \(-0.596\) & 0.85 & 0.89 \\ November & 1.554 * & \(-1.897\)* & \(-0.329\) & 0.751 & \(-0.292\) & 0.642 & 1.618* & \(-0.534\) & 0.838 \\ December & 0.786 & \(-3.182\)** & \(-2.128\)** & 1.126 & \(-1.399\) & 0.134 & 0.612 & \(-1.068\) & \(-0.079\) \\ \hline \hline \end{tabular} The significance levels tested are *** for \(p<0.001\), ** for \(p<0.01\), * for \(p<0.05\).  
\end{table} 
Table 2: The seasonal air temperature trends are based on 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 4 depicts the change point in the mean annual temperature over three historical periods in the headquarters, midstream, and downstream regions of the Varzob River Basin. The dramatic changes happened in 1976 (in Anzob station), 1976 (in Maykhura station), and 1971 (in Hushyori station) during the first period (1960-1990). For the Anzob, Maykhura, and Hushyori stations for the second period (1991-2018), the rapid changes in mean annual air temperature took place in 2007, 2000, and 1998. The dramatic change occurred for the Maykhura and Hushyori stations in 1998 for the full time (1960-2018) and for the Anzob station in 2007.