塔克拉玛干沙漠腹地的长波辐射变化特征

Characteristic of Long Wave Radiation over the Taklimakan Desert Hinterland

利用塔克拉玛干沙漠大气环境观测试验站(塔中站)实测的长波辐射资料,分析了流动沙漠区的长波辐射特征。结果表明:地表长波辐射能具体地反映地表失去热能的状况。在沙漠区,由于地表层的湍流运动较强以及下垫面温度与空气温度的差值较大,使得地表向大气传输的热通量较大,所以地面长波辐射值较大,有时接近于总辐射,最小值出现在日出前,最大值出现在15:00左右;由于大气中的水汽含量及云量较少,而沙尘气溶胶含量较高,所以大气长波辐射较大,沙漠区有效辐射也较大,为我国有效辐射年总量最高的地区之一。地表放射的净长波辐射在太阳总辐射中所占的比例小于地表反射辐射,只有在春、夏季两者较接近,且以反射辐射大些。区域气候变化过程中,沙漠加热场的强度是沙漠局地天气气候变化的主要影响因素之一。

Based on the long wave radiation data of Tazhong measured by atmosphere environment observation station, the characteristics of long wave radiation are analyzed in drift desert. The result shows that long wave radiation could concretely reflect the condition of heat energy loss of the surface. In desert, because of the strong turbulent flow and high temperature difference between underling and air tempera ture, it makes the heat flux is stronger transferring from surface to atmosphere, so the value of long wave radiation is larger, sometimes it is close to global radiation, which minimum value appears before sunrise, maximum appears at 15.00. In desert, it is due to the less water vapor in air, less cloud amount, but with more aerosol, the atmospheric long wave radiation is large too. Therefore, the effective radiation is larger, that which makes Taklimakan desert become one of the most larger regions of annual total of the effective in our country. The rate of net long wave radiation in total radiation is less than the surface reflective radiation, they are closed only in the summer, conversely the surface reflection radiation is greater. In the regional climate change process, the intensity of desert heating is one of the local desert climate change.