# Cross-Regional Pavement Temperature Prediction Using Transfer Learning and Random Forest
## 2 Methodology  
### Dataset Construction  
The data used in this study mainly included meteorological factors and pavement temperature at different depths. Air temperature, solar radiation intensity, relative humidity, and wind speed were selected as meteorological factors. These data were obtained from the WheatA V1.5.7 system [31]. Pavement temperature data were collected through long-term monitoring. Temperature sensors were buried in actual service pavements. Measurements were taken at depths of 0 cm, 5 cm, 12 cm, and 30 cm. Temperature monitoring was conducted in five cities: Ordos, Korda, Zhenjiang, Zhangzhou, and Kashgar. For clarity, the five cities were labeled as Site01, Site02, Site03, Site04, and Site05, respectively. Ordos (Site01), located in northern China, experiences a semi-arid continental climate characterized by substantial seasonal temperature variations. The average annual temperature is 6.2 \({}^{\circ}\)C, with extreme highs of 38 \({}^{\circ}\)C and lows of \(-\)31.4 \({}^{\circ}\)C. The region receives approximately 348.3 mm of annual precipitation, about 70% of which occurs between July and September. The average annual evaporation is around 2506.3 mm, roughly 7.2 times the total rainfall. Prevailing winds primarily come from the west and northwest. Korda (Site02), located in northwestern China, features a warm, temperate, arid climate typical of the Eurasian inland. The region receives abundant solar radiation, with approximately 2990 h of sunshine annually, and has an average annual temperature of 11.4 \({}^{\circ}\)C. It experiences a frost-free period of around 210 days, while its annual precipitation is extremely low, averaging only 58.6 mm. In contrast, the potential annual evaporation reaches up to 2788.2 mm. The prevailing wind direction is from the northeast. Zhenjiang (Site03), located in eastern China, has a subtropical monsoon climate characterized by hot, humid summers and mild winters. The average annual temperature is approximately 15.5 \({}^{\circ}\)C, and the annual precipitation is around 1100-1200 mm, mostly concentrated from May to September. The area is also influenced by typhoons and seasonal winds. Zhangzhou (Site04), located in southeastern coastal China, has a typical subtropical monsoon climate. The region receives abundant rainfall and sunshine, with an average annual temperature of approximately 21 \({}^{\circ}\)C and precipitation exceeding 1600 mm. Summers are long and hot, while winters remain short and mild. Coastal winds and typhoons are common during the summer and early autumn months. Kashgar (Site05), located in the southwestern region of China's Xinjiang Uygur Autonomous Region, has a typical continental climate with distinct seasons, intense solar radiation, and large diurnal and annual temperature variations. The annual average temperature ranges between 11 and 13 \({}^{\circ}\)C. Summers are hot, with maximum temperatures above 40 \({}^{\circ}\)C, while winters are relatively long and cold, with lows below \(-\)20 \({}^{\circ}\)C. Annual precipitation is minimal, ranging from 50 to 100 mm, and is primarily concentrated between June and August. Data from Site01 to Site04 were used for model training and prediction. Data from Site05 were used for independent validation. This approach was used to evaluate the cross-regional generalization ability of the model. Table 1 provides an overview of the meteorological factors and temperature data at each depth for all sites. It should be noted that the temperature sensor at 30 cm depth at Site04 experienced a malfunction during monitoring. As a result, the data at this depth were missing. These data were excluded from the subsequent analysis and modeling process. Figure 1a illustrates the process of the dataset construction.