# Cross-Regional Pavement Temperature Prediction Using Transfer Learning and Random Forest
## 3 Analysis of Meteorological Characteristics
### Correlation Analysis Between Meteorological Factors and Pavement Temperature  
IBM SPSS Statistics 27 was applied to examine how pavement temperatures at different depths relate to four meteorological variables in various regions. These variables included air temperature (AT), solar radiation (SR), relative humidity (RH), and wind speed (WS). The results in Table 3 show that the strength of the correlations changes with depth and region. This suggests that the effect of meteorological factors on pavement temperature is not consistent across different spatial locations and layers. To ensure the statistical significance of the correlation analysis, the critical correlation coefficients at the 0.05 significance level for each study region were calculated. Based on these thresholds, only the correlation coefficients exceeding the corresponding critical values were considered statistically significant. As shown in Table 3, AT exhibits a strong and stable positive correlation with pavement temperature across all depths. In all four regions, the correlation coefficients generally exceed 0.85 within the 0-30 cm range, indicating that AT serves as a primary meteorological factor influencing pavements' thermal behavior. The correlation coefficients first increase with depth and then decrease slightly. A high  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Regions**} & \multicolumn{2}{c}{**Temperature**} & \multirow{2}{*}{**AT**} & \multirow{2}{*}{**SR**} & \multirow{2}{*}{**RH**} & \multirow{2}{*}{**WS**} & **Critical** \\  & **at Different** & & & & & **Coefficient** \\  & **Depths** & & & & & **Coefficient** \\ \hline \multirow{3}{*}{Site01} & \(T_{0\,\mathrm{cm}}\) & 0.899 & 0.719 & \(-\)0.287 & 0.202 & \multirow{3}{*}{0.0214} \\  & \(T_{5\,\mathrm{cm}}\) & 0.973 & 0.501 & \(-\)0.201 & 0.226 & \\  & \(T_{12\,\mathrm{cm}}\) & 0.969 & 0.284 & \(-\)0.085 & 0.222 & \\  & \level is still maintained at 30 cm, indicating that the influence of air temperature extends to deeper pavement layers. SR also demonstrates a significant impact on surface and shallow pavement temperatures. Most of the correlation coefficients fall between 0.47 and 0.72. Notably, at Site01, the coefficient between SR and surface temperature reaches 0.719, highlighting a strong solar-driven effect on near-surface thermal conditions. However, the correlations decrease markedly with depth. At 30 cm, the lowest values are observed, indicating that the influence of solar radiation is primarily limited to the surface layers, with a reduced conductive impact on deeper sections. The correlation between RH and pavement temperature varies significantly across regions. At Site01, Site03, and Site 04, a negative correlation is observed, indicating that higher humidity tends to coincide with lower pavement temperatures. In contrast, a positive correlation is found at Site02, with the strength of the correlation increasing with depth. At 30 cm at Site02, the coefficient reaches 0.582, which exceeds the critical correlation threshold, indicating a statistically significant relationship. These results imply that the impact of humidity is closely related to geographic and climatic conditions, and that the underlying mechanism is complex. In comparison, WS shows a generally weak correlation with pavement temperature. Both positive and negative values appear, suggesting that WS has only a limited direct effect on pavements' thermal behavior. In summary, significant variations can be observed in the correlation between pavement temperature and meteorological factors at different depths across the four regions. Air temperature was identified as the primary influencing factor, while the impacts of solar radiation, relative humidity, and wind speed are more complex and exhibit strong regional dependence. To further investigate these relationships, data from the four regions were aggregated for correlation analysis.