The Spatial Distribution and Evolution Characteristics of North Atlantic Cyclones
The Spatial Distribution and Evolution Characteristics of North Atlantic Cyclones
复制标题
北大西洋气旋的空间分布及演化特征
DOI：
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
S. Gray
中科院分区：
文献类型：
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作者：
H. Dacre;S. Gray
利用基于1 km高度湿球位温梯度的客观识别气旋的方法，产生了热带气旋气候学。对气旋路径和生成密度统计进行了分析，发现该方法与其他气旋识别方法相比有较好的识别效果。北大西洋风暴路径是沿沿着与主要地区的成因。根据它们的起源位置对旋风进行分组，并确定相应的裂解区域。大多数穿越西欧的气旋都起源于东大西洋，那里的斜压性和海面温度梯度都比西大西洋弱。东大西洋气旋也有较高的1公里高度的相对涡度和较低的平均海平面压力在其成因点比西大西洋气旋。这与它们是在先前存在的“母”气旋的后缘上发展的次级气旋的假设是一致的。比较了西、东大西洋合成气旋的演变特征。它们的高层与低层强迫的比率表明，B型气旋在西大西洋和东大西洋都占主导地位，具有强烈的高层和低层特征。在其余的气旋中，东大西洋的C型气旋比例较高，而西大西洋的A型和C型气旋同样频繁。
A climatology of extratropical cyclones is produced using an objective method of identifying cyclones based on gradients of 1-km height wet-bulb potential temperature. Cyclone track and genesis density statistics are analyzed and this method is found to compare well with other cyclone identification methods. The North Atlantic storm track is reproduced along with the major regions of genesis. Cyclones are grouped according to their genesis location and the corresponding lysis regions are identified. Most of the cyclones that cross western Europe originate in the east Atlantic where the baroclinicity and the sea surface temperature gradients are weak compared to the west Atlantic. East Atlantic cyclones also have higher 1-km height relative vorticity and lower mean sea level pressure at their genesis point than west Atlantic cyclones. This is consistent with the hypothesis that they are secondary cyclones developing on the trailing fronts of preexisting “parent” cyclones. The evolution characteristics of composite west and east Atlantic cyclones have been compared. The ratio of their upper- to lower-level forcing indicates that type B cyclones are predominant in both the west and east Atlantic, with strong upper- and lower-level features. Among the remaining cyclones, there is a higher proportion of type C cyclones in the east Atlantic, whereas types A and C are equally frequent in the west Atlantic.