## 3 Results
### Correlation Analysis between ET and Driving Factors
#### 3.2.5 Correlation Analysis between Wind Speed and ET  
The correlation coefficient between ET and U ranged from \(-\)0.67 to 0.83, and the spatial average correlation coefficient was 0.01 (Figure 14a). As shown in Figure 10b, it could be seen that the area of regions with significant and extremely significant positive correlation between ET and U was 3.53%, of which only 0.75% was extremely significant positive correlation, which was concentrated in sub-basin D and H. The areas with significant and extremely significant negative correlation accounted for 1.78% of the total area of the basin, of which the area of extremely significant negative correlation was only 0.33% and was sporadically distributed in the middle and upper reaches of the YRB. In contrast, the non-significant correlated region between ET and U was relatively large, accounting for 94.69% of the total area of the YRB. In conclusion, only a few regions had significant correlation between U and ET at the annual scale.  
Figure 12: Spatial distribution map (**a**) and significance test results (**b**) of correlation coefficient between SH and ET at the annual scale in the YRB. A\(-\)M represent 13 sub-basins of the YRB, which are as follows: the Jinsha River Basin; the mountainous areas in the upper reaches of Dadu River and Jialing River; the confluence area of Sichuan Basin; the main stream area in the upper\(-\)middle reaches of the Yangtze River; the Wujiang River Basin; the middle reaches of the Yangtze River; the confluence area of Nanyang Basin; the Jianghan\(-\)Dongting Lake Plain; the Dongting Lake Basin; the mountainous area of Ganjiang River Basin; the Poyang Lake Plain; the confluence area of Chao Lake and the plain along Wanjiang River; and the confluence area of the Yangtze River Delta.  
Figure 13: Correlation significance test results of monthly SH and ET in the YRB. A\(-\)M represent 13 sub-basins of the YRB, which are as follows: the Jinsha River Basin; the mountainous areas in the upper reaches of Dadu River and Jialing River; the confluence area of Sichuan Basin; the main stream area in the upper\(-\)middle reaches of the Yangtze River; the Wujiang River Basin; the middle reaches of the Yangtze River; the confluence area of Nanyang Basin; the Jianghan\(-\)Dongting Lake Plain; the Dongting Lake Basin; the mountainous area of Ganjiang River Basin; the Poyang Lake Plain; the confluence area of Chao Lake and the plain along Wanjiang River; and the confluence area of the Yangtze River Delta.  
At the monthly scale, U and ET mainly showed non-significant correlation, followed by significant negative correlation, such as in February, April, and May, with the highest percentage of areas with significant negative correlation between U and ET in April, about 26.03%, distributed in the upper and middle reaches of the YRB (Figure 15). However, there were few areas where U was significantly positively correlated with ET, but the highest percentage was only about 10% in September. Similar to the performance at the annual scale, monthly ET and U were significantly correlated with ET in only a few regions in several months, such as January, March, August, and November. In particular, there were almost no areas with significant correlation between ET and U in July, August, and December in the headwaters of the YRB. In conclusion, the correlation between the two did not show obvious cyclical change.