青藏高原北麓河地区沥青路面辐射特征分析

沥青路面是寒区道路工程主要路面类型之一, 其对热量的吸收易诱发寒区道路病害. 在青藏高原北麓河试验场对沥青路面和天然地表的太阳辐射和地面辐射通量进行了观测, 对比分析了两种地面类型在能量辐射方面的差异. 结果表明: 天然地表的反照率是沥青路面的2~3倍. 沥青路面和天然地表的辐射通量总体呈夏季 >秋季 >春季 >冬季特点. 到达沥青路面的向下长、短波辐射量均大于天然地表, 沥青路面向上的长波辐射通量大于天然地表. 2009年9月-2010年8月沥青路面的净辐射量比天然地表多302.2 MJ·m^-2, 2010年9月-2011年8月向上的短波辐射相对增加, 使得沥青路面的净辐射量仅比天然地表多28.21 MJ·m^-2. 在5 cm深度, 沥青路面的温度比天然地表高约1.15~8.6 ℃. 对短波辐射的削减和对长波的吸收是其净辐射量增加的重要原因, 在能量辐射方面的差异是造成沥青路面吸热的重要原因之一.

Analysis of the radiation characteristics on asphalt pavement in Beiluhe section in the Tibetan Plateau

Asphalt pavement is one of the main road surfaces in cold regions, which has heat absorption, inducing diseases to road. Solar radiation and terrestrial radiation energy fluxes on the asphalt pavement and original surface were observed in the Beiluhe section on the Tibetan Plateau. At the same time, energy radiation differences between them are compared. The results showed that: albedo of original surface is 2 to 3 times more than that of asphalt pavement. Radiant fluxes of asphalt pavement and original surface show that: in summer >in autumn >in spring >in winter, overall. The long- and short-wave radiations reaching the asphalt pavement are greater than those reaching the original surface. Upward long-wave radiation flux of asphalt pavement is greater than that of original surface. Overall, the net radiation flux of asphalt pavement were 302.2 MJ·m^-2 more than that of original surface from September 2009 to August 2010. From September 2010 to August 2011, upward short-wave radiation increased relatively. As a result, the net radiation of asphalt pavement was 28.21 MJ·m^-2 more than that of original surface only. Reduction of short-wave radiation and increase in long-wave radiation absorption are the significant reason for the increase of net radiation. At 5-cm depth, temperature under asphalt pavement is greater than that under original surface about 1.15-8.6 ℃. The difference in the energy radiation is a distinct factor for asphalt pavement absorbing heat.