摘要
利用多普勒声雷达所获取的在时间、空间（垂直方向）较为密集的实时资料,对北京地区1997年12月18日平流大雾时的温度场和相应的水平风场的分布特征进行了分析;同时根据影响温度层结变化的因子,对逆温发展变化的不同阶段的各个因子进行了计算和分析。分析表明:（1）上层逆温与位于其顶部附近较为强劲的偏北气流是相伴出现的,其性质属下沉逆温。其逆温强度的变化与其顶部较为强劲的偏北气流变化同向。由于其本身处在较强的风切变之下,使其本身湍流不易发展,同时它也象盖子一样阻挡了上部动量和热量的下传,对近地层逆温的稳定维持也是至关重要的。（2）不论在逆温稳定维持阶段或是逆温大幅度减弱阶段,垂直运动都是逆温发展变化的主要控制因子。而地表的辐射冷却,对近地层逆温的影响,表现为较强的回波强度峰值,对应气温变化的谷值。
The distribution characteristics of the temperature field and the corresponding horizontal wind field with the advection fog on 18th December, 1997 are analyzed, using the relatively dense real time data on time and (normal) space collected by the Dopplar sonic radar. Meanwhile, all the factors in different periods of the temperature inversion's development are calculated and analyzed according to the factors affecting the temperature stratification change. The analysis demonstrates that: (1) The upper temperature inversion which is the subsidence inversion, appears together with the relatively strong deviating north air stream near to its top. The change of the intnsity of temperature inversion and the relatively strong deviating north air stream near to its top are in the same direction. The turbulence cannot develop easily because the upper temperature inversion is under the strong wind shear. Meanwhile, like a lid, it prevents the momentum and heat from transporting downward, which is essential for the ground layer temperature inversion to keep stability. (2) Whether in the maintaining period or in the dramatically weakening period, the normal motion is the main control factor of the temperature inversion's evolution. That the surface's radiation cooling affects on the ground layer temperature inversion is presented as the relatively strong echo peak value corresponding to the temperature variety's valley value.
出处
《热带气象学报》
CSCD
北大核心
2001年第4期443-451,共9页
Journal of Tropical Meteorology
