六盘山区雾的宏微观特征分析

Analysis on the Macroscopic and Microscopic Features of Fog in Liupan Mountains Areas

利用2014—2018年宁夏六盘山区隆德、泾源、六盘山气象观测站布设的前向散射能见度观测资料,分析了六盘山区雾的时空变化特征。结果表明,六盘山区雾具有明显的年、月、季、日变化特征。六盘山区年平均雾日数为53.7 d,月平均雾日数为22.4 d,秋季出现雾的次数最多,08:00出现雾的频次最高。六盘山站年平均出现雾日数为133.4 d,出现雾的次数远远高于其他地区;隆德站的雾通常出现在12:00之前,以辐射雾为主。最后,统计并分析了2019年12月1日至2020年11月30日六盘山站雾滴谱,发现其具有明显的月、日变化特征。有雾阶段的粒子数浓度、液态水质量浓度、粒径远远大于无雾阶段的对应参数值。雾滴谱呈单峰分布,粒子数浓度集中在小滴范围,而对于雾滴谱在中滴和大滴的粒子数浓度,有雾、有降水阶段要高于有雾、无降水阶段。

The temporal and spatial variation characteristics of fog in Liupan Mountains area were analyzed based the forward scattering visibility observation data in meteorological observation stations of Longde, Jingyuan and Liupanshan from 2014 to2018. The results show that the fog in Liupan Mountains area was with obvious annual, monthly, seasonally, and diurnal variation characteristics. The annual average number of foggy days in Liupan Mountains area was 53.7 days, and the monthly average number of foggy days was 22.4 days. There were the most foggy days in autumn, and the highest frequency of fog was at 8 a.m. The annual average number of foggy days in Liupanshan station was 133.4 days, which was much higher than that in other areas. The fog in Longde station, mainly radiation fog, usually appeared before 12 a.m. The fog droplet spectrum of Liupanshan Station from December 1, 2019 to November 30, 2020 was analyzed, and it was found to have obvious monthly and daily variation characteristics. The particle number concentration, liquid water mass concentration and particle size in the foggy stage were much larger than the corresponding parameter values in the fogless stage. The droplet spectrum shows a unimodal distribution. The particle number concentration is mainly in the small-droplet range, but in the middle-droplet and large-droplet ranges, it is higher in the stage with fog and precipitation.