## 3 Results
### Analysis of WUE in Anhui Province by Time Scale
#### 3.1.3 Trends in Spatial Changes in WUE in Anhui Province on Different Time Scales  
The overall distribution of WUE is also uneven in the year-averaged WUE spatial distribution map of Anhui Province (Figure 7a). Specifically, the WUE is higher in the hilly and mountainous area of southern Anhui and the Dabie Mountain area of west Anhui Province and lower in the Jianghuai hilly region and the plain alongside the river in the central part of the province. The topography is mainly hilly in southern Anhui and mountainous in the Dabie Mountain area in west Anhui. These areas have rich forest resources, sufficient soil moisture, and a climate suitable for vegetation growth; thus, these regions show the highest yearly average WUE in the province. The Huaibei Plain, an important grain-growing area in which large areas of corn, wheat, and other crops are grown, is located north of Anhui Province on the southern edge of a warm temperate zone, with favorable rain and heat conditions for crop cultivation and agricultural development. The central part of Anhui Province, specifically the Jianghuai hilly region and the plain alongside the river, showed the lowest WUE. This region is traversed by the Yangtze and Huaihe Rivers from west to east, with several cities concentrated within a small area and rice as the main crop. The low WUE in this region may be related to the high degree of urbanization, structure of agricultural cultivation, and manner in which the water resources are used. Figure 8 shows seasonal WUE trends, with clear differences in the significant trends in spring, summer, fall, and winter. Of all the seasons, spring and winter, especially winter, exhibited significant trend areas where the fluctuation in WUE was mainly concentrated in the Huaibei Plain, the northern part of the Dabie Mountains in western Anhui Province, and the river plain. In summer and fall, few highly significant trend points were observed, and water use efficiency was relatively stable with little fluctuation. \begin{table}
\begin{tabular}{c c c c c c c} \hline  & **Month** & \(\alpha_{\text{min}}\) & \(\alpha_{\text{max}}\) & \(\Delta\alpha\) & **f (\(\alpha\)min)** & **f (\(\alpha\)max)** & **\(\Delta\)f(\(\alpha\))** \\ \hline  & January & 1.9143 & 3.1780 & 1.2637 & \(-\)0.5752 & 1.5748 & \(-\)2.1499 \\  & February & 1.9141 & 3.2437 & 1.3296 & \(-\)0.8782 & 1.7050 & \(-\)2.5832 \\  & March & 1.9664 & 3.1348 & 1.1683 & \(-\)0.9424 & 1.9611 & \(-\)2.9035 \\  & April & 1.9440 & 3.1168 & 1.1728 & \(-\)0.8169 & 1.9449 & \(-\)2.7618 \\  & May & 1.9457 & 3.2338 & 1.2881 & \(-\)0.6615 & 1.9467 & \(-\)2.6081 \\ Average & June & 1.9503 & 3.1639 & 1.2136 & \(-\)0.6158 & 1.9505 & \(-\)2.5663 \\ monthly & July & 1.9592 & 3.3099 & 1.3507 & \(-\)1.0720 & 1.9570 & \(-\)3.0290 \\ WUE & August & 1.9600 & 3.8190 & 1.8590 & \(-\)1.4472 & 1.9572 & \(-\)3.4044 \\  & September & 1.9417 & 2.9046 & 0.9629 & 0.3274 & 1.9434 & \(-\)1.6160 \\  & October & 1.9628 & 2.8032 & 0.8404 & 0.2303 & 1.9592 & \(-\)1.7289 \\  & November & 1.9287 & 3.1144 & 1.1857 & \(-\)1.0604 & 1.7647 & \(-\)2.8251 \\  & December & 1.8696 & 3.2778 & 1.4083 & \(-\)0.8743 & 1.5451 & \(-\)2.4194 \\ \hline \end{tabular}
\end{table} 
Table 2: Parameters related to the WUE multifractal spectrum over 12 months in Anhui Province. Figure 9 shows the monthly trend changes in WUE from January to December. The distribution of significant trends varies significantly within the year, especially in January, February, and December; the distribution of highly significant and significant trend points is dense, which is consistent with the trend in winter, and the main range of changes is consistent with winter as a whole.