# Impacts of Drought and Heatwave on the Vegetation and Ecosystem in the Yangtze River Basin in 2022
## 3 Results  
### Spatiotemporal Dynamics of the 2022 Drought and Heatwave in the Yangtze River Basin  
The compound drought and heatwave in the Yangtze River Basin in 2022 was record-breaking, consistent with previous research findings [38]. In the research area, the global temperatures showed positive anomalies in both July and August (Figure 2a,b); in September and October, the central and southern regions maintained negative anomalies, albeit with a decreasing intensity, while the western and easternmost regions experienced negative anomalies (Figure 2c,d). In contrast, precipitation anomalies appeared more consistent, with predominantly negative anomalies throughout July to October, and a tendency toward southward movement of the anomaly center (Figure 2e-h). Figure 2i,j showed that the VPD in July and August mostly exhibited positive anomalies, with the anomaly center shifting from the west to the southeast. However, Figure 2k,l indicated that in the later period (September-October), the southwestern region showed opposite negative anomalies, consistent with the spatial-temporal distribution of temperature anomalies. In addition, with the increase in temperature and decrease in precipitation, soil moisture and air humidity also undergo changes. Apart from a special situation showed in Figure 3m, the spatial distributions of soil moisture anomalies across four different layers were generally consistent, characterized by predominantly negative anomalies, with a trend of the anomaly center shifting from the northwest to the central-eastern region (Figure 3). However, the deeper the layer, the lighter the anomaly intensity. SM1-SM3 also exhibited opposite positive anomalies in the southwestern region from September to October compared to other regions (Figure 3c,d,g,h,l), which is consistent with the peculiar phenomena observed in temperature and VPD. Figure 2: Spatial distributions of temperature, precipitation, and VPD anomalies in the Yangtze River Basin during July ((**a,e,i**) in 1 st row), August ((**b,f,j**) in 2 nd row), September ((**c,g,k**) in 3 rd row), and October ((**d,h,l**) in 4 th row) in 2022. The monthly averages of all environmental indices for the year 2022, along with their change percentages, are listed in Tables 2 and 3. An overall analysis reveals that the temperature and VPD columns from July to October in both tables are predominantly in red, while the remaining columns are mostly in blue. This indicates that during the summer of 2022, temperatures and VPD were significantly higher than usual, while precipitation and soil moisture content were notably lower than usual, which suggests a pronounced drought and heatwave event. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Month** & **Temperature** & **Precipitation** & **VPD** & **SM1** & **SM2** & **SM3** & **SM4** \\ \hline January & 273.1416 & 61.50192 & 1.50065 & 0.37011 & 0.36771 & 0.36318 & 0.39969 \\ February & 272.55076 & 59.88396 & 1.78544 & 0.37913 & 0.38209 & 0.38263 & 0.40034 \\ March & 282.0996 & 109.97059 & 4.27324 & 0.37094 & 0.37013 & 0.37371 & 0.40142 \\ April & 284.30708 & 141.87742 & 4.92106 & 0.38383 & 0.38629 & 0.38301 & 0.4045 \\ May & 287.71506 & 153.96961 & 4.94959 & 0.385 & 0.38607 & 0.38705 & 0.40828 \\ June & 292.55077 & 213.31838 & 6.113 & 0.39408 & 0.39336 & 0.38498 & 0.41264 \\ July & 295.16993 & 140.01088 & 8.87914 & 0.35136 & 0.35281 & 0.35186 & 0.40851 \\ August & 296.51411 & 92.07134 & 11.40851 & 0.28761 & 0.29172 & 0.30846 & 0.39665 \\ September & 290.9224 & 52.59121 & 7.65444 & 0.3291 & 0.3274 & 0.3183 & 0.38783 \\ October & 285.35649 & 38.47303 & 5.28278 & 0.33866 & 0.33989 & 0.33847 & 0.38678 \\ November & 281.78179 & 33.20679 & 3.33306 & 0.34682 & 0.34157 & 0.33459 & 0.38434 \\ December & 274.39817 & 11.53739 & 2.57534 & 0.34734 & 0.35417 & 0.34788 & 0.38213 \\ \hline \hline \end{tabular}  
* In this table, the unit for temperature is \(\kappa\), the unit for precipitation is mm, the unit for VPD is hPa, and SMI–SM4 are untilles.  
\end{table}