Study of unusual atmospheric icing at Mount Zao, Japan, using the Weather Research and Forecasting model
Study of unusual atmospheric icing at Mount Zao, Japan, using the Weather Research and Forecasting model
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使用天气研究和预报模型研究日本藏王山的异常大气结冰
DOI：
10.1029/2011jd017042
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发表时间：
2012
影响因子：
--
通讯作者：
E. P.
中科院分区：
文献类型：
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作者：
Podolskiy;E. Y.;Nygaard;B. E. K.;Nishimura;K.;Makkonon;L.;and Lozowski;E. P.
本文采用了一个中尺度大气模式，即天气研究与预报模式（WRF），重建了日本枣山春季中期的雾凇形成过程。人们观察到一种特别有趣和罕见的雾凇。这些地层是羽状的、不透明的颗粒冰聚集体，长15-30厘米，在日语中被称为“虾尾”。通过对模型生成结果的分析，我们发现在Jizosancho索道站，模型和观测的风和温度时间序列具有很好的定量一致性。我们确定了两个结冰事件（分别持续36和41小时，地表气温在- 6.3°和- 0.1°C之间，相对恒定的西风高达26 m s - 1，最大云液态水含量（LWC）在0.72和1.05 g m - 3之间）。我们证实，高分辨率模型（1.1 km网格间距）比粗网格（10和3.3 km）的模拟要准确得多。利用WRF模型首次估算了这种罕见类型结冰形成期间的LWC，发现它比以前实验研究中使用的值高出几倍。我们发现，这种类型的“尾”霜的联合风速-空气温度分布更类似于硬霜或釉，而不是软霜。我们通过风的撞击角度解释了“虾尾”的形成，并报告了先前关于其对液滴碰撞效率和霜冰密度影响的实验室结果。
A mesoscale atmospheric model, the Weather Research and Forecasting model (WRF), was used for a case study that reconstructs mid‐spring episodes of rime formation at Mt. Zao, Japan. One particularly interesting and rare form of rime was observed. The formations were feathery, opaque aggregates of granular ice 15–30 cm long, called “shrimp tails” in Japanese. Based on an analysis of model‐generated results, we find good quantitative agreement of modeled and observed wind and temperature time series at Jizosancho ropeway station. We identified two icing events (lasting for 36 and 41 h respectively, with surface air temperatures between −6.3° and −0.1°C, relatively constant westerly winds up to 26 m s−1, and maximum cloud liquid water contents (LWC) between 0.72 and 1.05 g m−3). We confirmed that high‐resolution modeling (1.1 km grid spacing) was much more accurate than simulations with coarser grids (10 and 3.3 km). The LWC during the formation period of this rare type of icing was estimated for the first time using the WRF model at Mt. Zao, and it was found to be up to several times higher than values previously used in experimental studies. We found that the joint wind speed‐air temperature distribution for this type of “tail” rime was more similar to that of a hard rime or glaze, than to a soft rime. We explain the formation of “shrimp tails” by wind impact angle and report previously made laboratory results on its effect on the droplet collision efficiency and the density of rime ice.