飑线

The low-level wind field displayed cyclonic character on the north part of the squall line, whereas on its south part the wind field pattern was anticyclonic, with clear convergence of westerly and southeast inflows in between.

飑线不同位置的水平风场结构有很大不同，在飑线北端，低层是气旋性辐合风场，飑线南端是反气旋性辐合风场，而中部沿强对流窄带的前部是偏西和东南风的风场辐合。

The physical causes of the surface strong wind caused by the squall line are also discussed.

针对2006年4月28日发生在江苏境内的一次飑线过程，分析了过程期间的边界层特征、垂直结构和飑线的传播演变特征，讨论了飑线造成地面强风的物理原因。

The squall line, including surface wind and squall line structure, is simulated well by the WRF model.

3WRF模式对这次飑线过程的主要特征模拟较好，包括地面风场和飑线的结构。

The results show that this squall line is a combination of follow-up type and consecutive type.

分析飑线整体演变和内部对流单体演变表明：此飑线为后续线型和断续线型的结合。

According to short term monitoring data, it appears that the new cell echo before the radar echo is advantage for the development and maintenance of the squall line. And the initialization of new cell is associated with boundary-layer convergence line. As a result, mesonet data is useful fur to research on squall line.

从短时监测的资料分析，飑线发展过程中，雷达主回波前方的新生的回波单体对飑线发展和持续十分有利，而它的新生与边界层的辐合线相联系，因此，充分利用中尺度地面观测资料有助于飑线的发展研究。

The results suggest that the squall line occurred under the favorable weather conditions.

结果表明：飑线是在有利的天气形势下发生的，飑线上强风暴的强度大、高度高；飑线速度剖面图中显示有低层辐散、中层辐合、高层辐散的特征；垂直累积液态水含量迅猛增加到比较大的数值对冰雹预报有很好的指示意义；在冰雹指数产品中以强冰雹概率大于30%作为冰雹预警门限则有较好的效果；边界层辐合线起到了触发对流和加强对流的作用。

The result shows that the severe convection weather arise in the transition from verticality to forward slant of the upper trough, so there was a different advection between the mid- and lower- troposphere, which was quite important to the formation and development of convective instability. The event was triggered by the surface low and meso-scale convergence line, and the squall line was direct influencing system.

结果表明：这次强对流天气过程发生在高空槽由垂直结构向前倾结构转变的过程中，中高层干冷平流、低层暖湿平流的大气层结增强了对流不稳定的发展，飑线是此次强对流天气的直接影响系统；太行山地形和平原南部的中尺度辐合线，对飑线系统的触发、组织、移动具有重要作用，强对流区发生在地面中尺度辐合线南侧的偏南气流里。

The strong sandstorm was caused by squall line activity of eastern Hexi Corridor in Apr. to Jun. that was cold front, majority is in May, four times strong sandstorm is accompanied by the squall line in seven times. It was explained that the squall line was suggested easily when the strong cold front moved east to Hexi Corridor where special canyon tube terrain was in, the strong sandstorm which was created by squall line activity have very strong paroxysm that often created serious disaster.

河西走廊东部的飑线活动造成的强沙尘暴出现在4~6月，均为冷锋型，其中5月居多，出现的7次强沙尘暴中有4次伴有飑线，说明5月份强冷锋东移经河西走廊特殊峡管地形时易诱发飑线，飑线活动造成的强沙尘暴爆发性强，往往造成严重灾情。

The severe storms on the squall line had large radar reflectivity and high tops of echoes. There was a divergence at lower level, a convergence at middle level, and a divergence at upper level in the velocity cross section of the squall. The VIL (Vertical Integrated Liquid water) of the storms increased rapidly to a large value, which is a good indictor of hailstorm. When the probability of severe hail is larger than 30% according to the hail index products, a hail storm is very likely to happen. The convergence line in the boundary can trigger and intensify convections.

结果表明：飑线是在有利的天气形势下发生的，飑线上强风暴的强度大、高度高；飑线速度剖面图中显示有低层辐散、中层辐合、高层辐散的特征；垂直累积液态水含量迅猛增加到比较大的数值对冰雹预报有很好的指示意义；在冰雹指数产品中以强冰雹概率大于30%作为冰雹预警门限则有较好的效果；边界层辐合线起到了触发对流和加强对流的作用。

The result showed that the strong storm followed by mesoscale squall line was primary cause of strong sandstorm producing, steps and ladders short wave trough of 500 hPa was great criterion triggering system for the mesoscale squall line producing, the essential dynamic condition was provided by distortion field and the mesoscale low pressure of 700 hPa for the strong sandstorm forming and maintaining in mid-west of Hexi Corridor, the deep vertical circulation development condition was basic power that urged squall line to occur and sand dust to curl up, which was provided for the deep convection development by superimposition of lifting movement before ground cold front and ascendant current of secondary circulation in upper air jet entrance region, temperature and the barometric gradient around the cold front was enlarged by enhancement of ground thermal low and temperature diurnalvariation of afternoon, by which essential thermal energy unstable condition was provided for the gale and strong sandstorm eruption, the strong sandstorm appeared in downstream of -200 m^2s^(-2) center of vertical helicity, the vertical helicity had good instruction significance for development of squall line and landing region of sandstorm, the mesoscale squall line occurred in unstable stratification, basic condition of potential energy transforming as kinetic energy was provided by strong unstable stratification for the strong sandstorm forming and developing.

结果表明：中尺度飑线所伴随的强风暴是产生强沙尘暴的主要原因；500 hPa阶梯短波槽是中尺度飑线产生的大尺度触发系统，河西走廊中西部700 hp变形场、中尺度低压为强沙尘暴形成和维持提供了必要的动力条件；地面冷锋前上升运动与高空急流入口区次级环流的上升气流的叠加，为深对流发展提供了深厚的垂直环流发展条件，是促使飑线发生和沙尘卷起的基本动力；地面热低压的加强和午后气温的日变化加大了冷锋前后的温度和气压梯度，为大风、强沙尘暴爆发提供了必要的热力不稳定条件；强沙尘暴出现在垂直螺旋度为－200平方公尺/s^2中心的下游，垂直螺旋度对飑线的发展和沙尘暴的落区具有较好的指示意义；中尺度飑线发生在不稳定层结内，较强的不稳定层结为强沙尘暴形成、发展提供了位能转化为动能的基本条件。

As she looked at Warrington's manly face, and dark, melancholy eyes, she had settled in her mind that he must have been the victim of an unhappy attachment.

每逢看到沃林顿那刚毅的脸，那乌黑、忧郁的眼睛，她便会相信，他一定作过不幸的爱情的受害者。

Maybe they'll disappear into a pothole.

也许他们将在壶穴里消失