Abstract:

Daily meteorological data from an automated traffic observatory on the Qaidam Hinterland section (built between March 1, 2018, and February 29, 2020) of the Beijing-Tibet Expressway was used to analyze the characteristics of road surface temperatures and hourly air temperature variations in the four seasons. Next, the correlation between the maximum and minimum road surface temperatures and the maximum and minimum air temperatures was calculated. Finally, we established correlation equations between the maximum and minimum road surface temperatures and the maximum and minimum air temperatures to provide a reference for detailed road surface temperature forecasting services. The results show that the road surface temperatures and air temperatures of the three stations in the Qaidam Hinterland section of the Beijing-Tibet Expressway have distinct seasonal daytime variation characteristics. Furthermore, road and air temperatures do not reach their minimum and maximum values simultaneously. The road surface temperatures at the three stations rose faster than the air temperatures after 09:00. The road surface temperature rise level reached before the air temperature rise level. During 10:00-18:00, there was a big difference between the road surface temperature and air temperature at all stations. The average road surface temperature at Ekgoli station was constantly lower than that at Zongjia Town and Big Gle station. The average air surface temperature variations at the three stations were consistent, and the daily difference in average air temperature between winter and autumn was noticeable. The correlation equations between the maximum and minimum road surface temperatures and the maximum and minimum air temperatures at Ekgoli, Zongjia, and Big Gle are realistic and can be put into practical use.

Key words: Beijing-Tibet Expressway, Qaidam Hinterland, road surface temperature, correlation equation