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利用黄土高原中部庆阳观测站冬季的观测资料,分析了黄土高原台塬区微气象特征。研究表明,黄土高原中部冬季晴天辐射各分量的值几乎比夏季的小一半。09:00～17:00,地面给大气加热,在17:00至次日09:00,大气给地表加热。平均辐射与晴天时更接近。无论是晴天还是平均气候状况,冬季感热在地表能量中都占有很大比重,几乎占到净辐射值的一半;潜热峰值只有感热峰值的1/4左右,土壤热通量介于感热和潜热之间。冬季夜间近地层的湍流交换十分微弱,在一天中的2/3时间里,大气给地表传递热量。在无降水时段,地表反照率平均为0.22,降雪的影响使地表反照率的平均值为0.28,增大了约30%。地表反照率恢复到一个新的准平衡态长达7天。降雪过程对地表反照率的影响是一个非常复杂的过程,这也是地表反照率难以准确参数化的原因之一。
Based on the observation data of the Qingyang Observatory in the central part of the Loess Plateau in winter, the micrometeorological features of the Loess Plateau are analyzed. The research shows that the value of each component in the sunny winter in central Loess Plateau is almost half that of summer. 09: 00 ~ 17: 00, the ground to the atmosphere heating, at 17:00 to 09:00 the next day, the atmosphere to the surface heating. The average radiation is closer to the sunny day. Whether in sunny or average climatic conditions, winter sensible heat accounts for a large proportion of surface energy, accounting for almost half of the net radiation value. The peak value of latent heat is only about 1/4 of the peak value of sensible heat, and the soil heat flux is between the sensible heat And latent heat between. The turbulent exchange near the ground during winter night is very weak, and the atmosphere transfers heat to the Earth’s surface in two-thirds of a day. In the non-precipitation period, the average surface albedo is 0.22. The influence of snowfall makes the average value of surface albedo 0.28, an increase of about 30%. Surface albedo restored to a new quasi-equilibrium for up to 7 days. The influence of snowfall on surface albedo is a very complex process, which is one of the reasons why it is difficult to accurately parameterize the surface albedo.