## 3 Results
### Short-Term Large Scope IST-Cube  
In contrast to Figures 8 and 10, the index in Figure 11b and Figure 14b denotes the occurrence of short-term IST-cubes. The higher the value, the more frequent the changes that cause such short-term IST-cubes in the study region. Figure 11b shows that the SL IST-cube most often exists in forests, which are located in the eastern region of the study area. Forests are sensitive to meteorological conditions. However, the study area is prone to meteorological disasters. The SL IST-cube is characterized by a short period, but a large influence range, which reflects the characteristics of meteorological disasters. Consequently, SL changes may be explained by meteorological disasters. Figure 12 shows the precipitation and drought from 1987-2019. Figure 12 and Table 2 indicate that the years in which change was detected were those characterized by floods or droughts. Figure 11: (**a**) Actual SL IST-cube diagram containing two layers representing two years. The average number of pixels per year is 14 647, conforming to the criterion for the SL IST-cube class. (**b**) Spatial distribution map of occurrence number for the SL IST-cube. Figure 10: (**a**) Spatial distribution map of the mean time length of the LS IST-cube. (**b**) Actual LS and increasing IST-cube diagram, containing five layers representing five years, with an increasing number of pixels per year, conforming to the LS and increasing IST-cube classes. (**c**) Spatial distribution map of the mean time length of the LS and increasing IST-cube classes. (**d**) Actual LS and fluctuating IST-cube diagram, containing six layers representing six years, with a fluctuating number of pixels per year, conforming to the LS and fluctuating IST-cube classes. (**e**) Spatial distribution map of the mean time length of the LS and fluctuating IST-cube classes. (**f**) Actual LS and stable IST-cube diagram, containing 13 layers representing 13 years, where the number of pixels per year is constant, conforming to the LS and stable IST-cube classes. (**g**) Spatial distribution map of the mean time length of the LS and stable IST-cube classes. Figure 12: Precipitation and drought for 1987–2019. (**a**) Maximum precipitation and flood threshold for 10 consecutive days and (**b**) proportion of drought periods. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Year** & **Flood** & **Dropout Class** & **Is Detected** \\ \hline
1987 & none & Severe & no \\
1988 & none & Moderate & yes \\
1989 & moderate & Moderate & no \\
1990 & none & Mild & yes \\
1991 & none & Severe & no \\
1992 & moderate & Mild & yes \\
1993 & none & Mild & no \\
1994 & none & None & no \\
1995 & none & None & no \\
1996 & mild & Moderate & yes \\
1997 & mild & Moderate & no \\
1998 & mild & Mild & yes \\
1999 & none & Severe & no \\
2000 & mild & Moderate & no \\
2001 & mild & None & no \\
2002 & none & Mild & no \\
2003 & none & Mild & no \\
2004 & none & Severe & no \\
2005 & none & Severe & no \\
2006 & severe & Moderate & yes \\
2007 & mild & Moderate & no \\
2008 & none & Severe & yes \\
2009 & none & Severe & no \\
2010 & mild & Severe & yes \\
2011 & none & Severe & no \\
2012 & none & Mild & yes \\
2013 & mild & None & no \\
2014 & none & Mild & yes \\
2015 & none & Moderate & no \\
2016 & mild & None & yes \\
2017 & none & Moderate & no \\
2018 & none & Mild & no \\
2019 & mild & Mild & no \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Occurrence of floods, droughs, and changes detected by the IST-cube for 1987–2019. In contrast to Figures 8 and 10, the index in Figure 11b and 14b denotes the occurrence of short-term IST-cubes. The higher the value, the more frequent the changes that cause such short-term IST-cubes in the study region. Figure 11b shows that the SL IST-cube most often exists in forests, which are located in the eastern region of the study area. Forests are sensitive to meteorological conditions. However, the study area is prone to meteorological disasters.