太阳辐射对青藏铁路路基表面热状况的影响

在不考虑大气影响的情况下,铁路路基和左右边坡接受到的太阳辐射日总量随铁路走向和季节的不同,而有很大的差异.利用实测资料,计算了青藏铁路梯形路基不同表面吸收的太阳辐射能的差异,分析研究了青藏铁路路基及左右边坡表面的热状况及其与地面吸收的太阳辐射能的关系,提出了一些有关高原铁路建设方面值得注意的问题.利用地面吸收的太阳辐射能反演了青藏铁路路基和边坡表面温度,并进行了验证,从而得出了一个计算路基和边坡表面温度的简单参数化方法.

Influence of Solar Radiation on Embankment Surface ThermalRegime of the Qinghai-Xizang Railway

Under the assumption of no atmospheric influence on solar radiation transfer, the daily solar radiation amount on railway surface was calculated in one year cycle. Generally the discrepancy of daily solar radiation amount on bothroad-slopes was obviously and varied with season and railway direction. By using the dataset of GAME-Tibet IOP 98 in a fair day in Amdo of the Tibetan Plateau on July 16, 1998, the surface absorptionradiation and some radiation parameters on roadbedand road-slopes were presented. The results show that the daily variation of surface absorptionradiation on both road-slopes varied with railway direction. The discrepancy of surface absorptionradiation between both road-slopes appeared a multi-peak structure in one-day cycle. And the values of these peaksincreased while the railway direction changed from eastward to northward. The discrepancy of daily surface absorptionradiation amount between both road-slopes also varied with railway direction, higher on southeastward railway and lower on northeastward railway. So it is better to construct the railway on tundra region as northeastern direction to reduce the unsymmetrical effect of radiation heating on bothroad-slopes. Further more, the relationship between the railway thermal regime and surface absorptionradiation was linked to design a simple parameterization scheme to retrieve the ground surface temperature on roadbed and both road-slopes.The retrieved ground surface temperature basically agreed the observed one on roadbed. Even so, it is necessary to introduce other variables that affected the ground surface temperature, such as cloud amount, precipitation, air temperature and so on, to improve thisparameterization scheme.