## 4 Results
### Snow Cover Analysis in the Varzob River Basin
Their study indicated that the trends along the Syr Darya River and Amu Darya River did not fully apprehend the inconsistency across various features and other topographical factors. An increasing rate of warming does have a greater effect at higher elevations, according to the trends analysis across elevation bands [62]. Nonetheless, there is still potential to determine more localized trends within each basin to better understand the spatial variability in mountainous regions. This study applied the snow cover data from the MODIS in the Varzob River Basin in Amu Darya River Basin. It should be noted that MODIS images have been extracted which have less than a 10 percent cloud. The MODIS satellite data are available for the period of 2001-2022, which is used to analyze snow cover in the region of interest. Therefore, the study is limited to this time period as it is the only period for which the necessary data are available. Figure 9 shows the MK trend test based on the p-value. The \(p\)-value is a statistical metric that helps define whether the observed snow cover trend is more likely to be a real and significant trend or just the result of chance or random variation in the data. The p-value for our study was found to be less than 0.05, which means that there is a 95% probability that the observed trend in snow cover is real and significant rather than the result of chance or random variation in the data. Accordingly, the snow cover trend is regarded as statistically significant at a 95% confidence level [63]. The MK test was applied to analyze the snow cover area trend. Figure 9 shows the overall monthly snow cover trends of the study area. Our results indicate the overall decreasing trend in snow cover area during February, September, and November and an increasing trend in July. We further analyzed the snow cover trends at three available station-based data and describe these results in Table 6. We observed that, at a height elevation area, the snow cover area showed a decreasing trend spatially in the winter season. Hushyori station belongs to the low elevated region and showed the decreasing trend during most of the months. These results explain the clear picture of the snow cover area overall, and at the evolution level, show trends on a monthly basis in the VRB. The decreasing trend in February and September could be more of a concern about the hydrological system of the study area because these months relate to the season shifting month, and the trend results indicate the intensity of the warming conditions in VRB during the period 2001-2022. In our study area, the heatmap reveals some interesting trends. Understanding the snow cover dynamics can be helped by looking at the heatmap, which provides a visual depiction of the patterns and changes in snow cover area over time and across several months (Figure 10). The heatmap demonstrates that, as is typical for most places, the maximum amount of snow cover is in winter (December-February) and the minimum is in summer (June-August). Likewise, the amount of snow cover over the period represented in our heatmap may vary slightly from year to year. The X axis also appears to indicate some variation in snow cover from year to year, with some years having higher snow cover than others. The spatial patterns of snow cover also vary across the years. For instance, some years show a more widespread snow cover over the study region, while the other years show a sparser snow cover. In the Varzob River Basin, the sum of the snow cover area from January to December was found for 13,013 km\({}^{2}\) in 2014 and 9063 km\({}^{2}\) in 2007,