Convection forced by a descending dry layer and low-level moist convergence
Convection forced by a descending dry layer and low-level moist convergence
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下降的干燥层和低层潮湿辐合迫使对流
DOI：
10.1111/j.1600-0870.2008.00382.x
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
Russell A
中科院分区：
文献类型：
--
作者：
Russell A
2005年7月18日，在对流风暴启动项目(CSIP)期间，在英格兰南部观测到一条窄线对流阵雨。阵雨形成在冷锋(CF)后面，在两个明显下降的干燥层(即倾斜的，使它们相对于观测它们的仪器下降)之下。最低的干层与来自低气压的对流层顶褶皱有关，该低气压在2天前由位于英国西北部的罗斯比波破裂而形成。由于围绕凹陷的旋转，最上面的干层已经从原始流光中碎裂(这种旋转也是观测到明显下降的原因--否则将在CF后面看到上升)。最低的干层降落在英国上空，并淹没了它下面的较高的θWare，导致潜在的不稳定。与地面辐合线(它触发了对流，但对对流可用势能的影响小于位势不稳定)相结合，对流被强迫到5.5公里处，最上面的干层覆盖了对流。可能发生对流的时间很短，这就解释了为什么淋浴带很窄。对流风暴启动项目的观测和模式数据被用来说明在这种情况下的独特过程。
A narrow line of convective showers was observed over southern England on 18 July 2005 during the Convective Storm Initiation Project (CSIP). The showers formed behind a cold front (CF), beneath two apparently descending dry layers (i.e. sloping so that they descended relative to the instruments observing them). The lowermost dry layer was associated with a tropopause fold from a depression, which formed 2 d earlier from a breaking Rossby wave, located northwest of the UK. The uppermost dry layer had fragmented from the original streamer due to rotation around the depression (This rotation was also responsible for the observations of apparent descent—ascent would otherwise be seen behind a CF). The lowermost dry layer descended over the UK and overran higher θwair beneath it, resulting in potential instability. Combined with a surface convergence line (which triggered the convection but had less impact on the convective available potential energy than the potential instability), convection was forced up to 5.5 km where the uppermost dry layer capped it. The period when convection was possible was very short, thus explaining the narrowness of the shower band. Convective Storm Initiation Project observations and model data are presented to illustrate the unique processes in this case.
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DOI：
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发表时间：
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DOI：
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发表时间：
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