A field study of radiation fog in meppen, West Germany
A field study of radiation fog in meppen, West Germany
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DOI：
10.1002/qj.49710745209
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发表时间：
1981-04
影响因子：
8.9
通讯作者：
T. Choularton;G. Fullarton;J. Latham;C. Mill;M. H. Smith;I. Stromberg
中科院分区：
文献类型：
--
作者：
T. Choularton;G. Fullarton;J. Latham;C. Mill;M. H. Smith;I. Stromberg
1978 年 2 月 17 日，在西德梅彭对辐射雾的微物理特性进行了实地研究。研究根据当时的气象条件进行了描述和解释。在辐射雾中有时观察到液态水含量的明显周期性波动（间隔~70秒）。有人认为这是贝纳德环流形式的对流运动的结果。液滴尺寸分布很宽，包含半径高达 25 μm 的液滴。计算表明这些较大的水滴不能通过雾顶的辐射冷却产生。有人认为，这些大水滴可能是由雾顶附近的大过饱和波动产生的，这种波动是由于向下夹带较温暖潮湿的空气而产生的，或者是由于对流运动导致一部分较大水滴多次移动到雾顶附近的辐射冷却区域而产生的。当云在该地点上空平流时，观察到辐射雾消散。有人认为，这主要是由于雾顶的辐射冷却被云层严重限制后，涡流扩散和液滴到地面的重力沉降造成的。
A field study of the microphysical properties of a radiation fog was conducted in Meppen, West Germany, on 17 February 1978. It is described and interpreted in terms of the prevailing meteorological conditions. Pronounced periodic fluctuations in liquid water content (intervals ∼70s) were observed at times in the radiation fog. It is suggested that these were a result of convective motions in the form of Benard cells. the drop size distributions were broad, containing drops of radii up to 25 μm. Calculations indicate that these larger drops cannot be produced by radiative cooling from the fog top. It is argued that these large drops may have been produced either by large supersaturation fluctuations near the fog top, resulting from downwards entrainment of warmer moister air, or by convective motions causing a fraction of the larger drops to make several excursions to the radiative cooling region near the fog top. the radiation fog was observed to clear when cloud was advected over the site. It is suggested that this was due mainly to eddy diffusion and gravitational sedimentation of drops to ground, after radiative cooling from the fog top had been severely curtailed by the cloud layer.