Atmospheric Fronts: An Observational Perspective

作者：Daniel Keyser · 发表于：American Meteorological Society eBooks · 年份：1986 · DOI：10.1007/978-1-935704-20-1_10 · 被引用次数：43 · 研究领域：Climate variability and models、Meteorological Phenomena and Simulations、Atmospheric aerosols and clouds

Atmospheric fronts may be defined as sloping zones of pronounced transition in the thermal and wind fields. Consequently, they are characterized by a combination of relatively large horizontal temperature gradients, static stability, absolute vorticity (horizontal wind shear), and vertical wind shear. When depicted on quasi-horizontal surfaces, fronts appear as long, narrow features in which the along-front scale is typically an order of magnitude greater than the cross-front scale (1000–2000 km compared with 100–200 km). Therefore, according to the scale definitions of Orlanski (1975), the along-front dimension is meso- α (200–2000 km), and the cross-front dimension is meso- β (20–200 km). The scale of the middle-latitude baroclinic waves in which fronts are embedded ranges from meso- α to macro- β or synoptic (2000–10,000 km). Fronts are shallow phenomena, with depths typically 1–2 km. Because of this geometrical configuration, horizontal variations in the cross-front direction greatly exceed those in the along-front direction. These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.