The Morning Transition of the Nocturnal Boundary Layer
The Morning Transition of the Nocturnal Boundary Layer
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夜间边界层的早晨转变
DOI：
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发表时间：
2006
期刊：
影响因子：
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通讯作者：
A. Lapworth
中科院分区：
文献类型：
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作者：
A. Lapworth
分析了地面仪器站点六年的观测结果，以确定影响早晨大气边界层加热期间近地面风和湍流热通量发展变化的时间和因素。近地面风速和屏幕温度之间的一个简单的关系，以及一个预测方程的早晨过渡空气温度已经发现。安装在系留气球上的探测器的剖面测量已被用来补充表面数据，并研究这些表面关系的基础过程。结果证实了早期的工作，并表明，在早晨过渡之前和之后，几乎所有的加热在地面层是由于湍流扩散从上面。为了解释所涉及的关系的机制，一个简单的有限差分模型已经运行，并验证对配置文件数据。模型的预测进行了比较，在早上和晚上的观测和不同的温度分布相关的差异。根据计算结果，给出了地面风速和转捩温度的数值预报规则。
Six years of observations from a surface instrument site have been analysed to determine timings and factors influencing developmental changes in the near-surface wind and turbulent heat fluxes during the morning heating of the atmospheric boundary layer. A simple relationship has been found between near-surface wind speed and screen temperature, together with a predictive equation for the morning transition air temperature. Profile measurements from a probe mounted on a tethered balloon have beenused to supplement the surface data and study the processes underlying these surface relationships. The results have confirmed earlier work and have shown that both before and immediately after morning transition, almost all heating in the surface layer is due to turbulent diffusion from above. In order to explain the mechanisms involved in the relationships, a simple finite difference model has been run and validated against the profile data. The model predictions are compared with observations during both the morning and evening and the differences related to the different temperature profiles. Numerical forecasting rules for the surface wind speed and transition temperature are derived from the results.