Classification of mesoscale vortices in polar airstreams and the influence of the large-scale environment on their evolutions
Classification of mesoscale vortices in polar airstreams and the influence of the large-scale environment on their evolutions
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极地气流中尺度涡分类及大尺度环境对其演化的影响
DOI：
10.3402/tellusa.v37i2.11661
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发表时间：
1985
期刊：
影响因子：
2
通讯作者：
Walter D Lottes
中科院分区：
文献类型：
--
作者：
G. Forbes;Walter D Lottes
本文利用卫星图象对1981年12月1日至1982年1月5日发生在大西洋东北部及其邻近海域的133个中尺度云系涡旋进行了探测和研究。只考虑了出现在冷空气中的涡旋，与天气尺度的锋面云带分开。每个云涡的演变的完整历史记录在其位置，大小，云的模式，云的类型（浅或深;层状或对流）。一旦记录了所有的涡流，就查阅了传统的气象数据和分析。这项研究的目的之一是确定卫星图像是否可用于估计伴随中尺度涡旋的气旋的中心压力。其他目标是确定（1）中尺度云结构或（2）与发展成极地低压的涡旋相比仍然不显著的大尺度涡旋环境是否存在显著差异。结果表明，极涡的亏损压力可以从卫星图像估计，并有发展和非发展的涡旋之间的可识别的差异。只有少数云的配置伴随着极地低压，而在涡旋存在的早期阶段出现的某些其他配置表明，这些涡旋将保持微不足道。天气尺度环境似乎在决定哪些初期涡旋继续发展方面起着相当大的作用。适度的斜压性（水平温度梯度和垂直风切变）、相对较弱的风、大的直减率和有利的涡度平流伴随着极地低压的发展。不发展的涡有不利的涡度平流。其中，一些涡能够在最初发展为中等扰动，此后保持稳定。这些涡与不显著涡的明显区别在于，定常涡的斜压性更强，直减率也更陡。DOI：10.1111/j.1600-0870.1985.tb00276.x
Satellite imagery was used to detect and study 133 mesoscale cloud vortices which occurred in the northeastern Atlantic Ocean and adjacent seas between 1 December 1981 and 5 January 1982. Only vortices occurring in cold air, separate from synoptic-scale frontal cloud bands, were considered. The complete history of the evolution of each cloud vortex was recorded in terms of its location, size, cloud pattern, and cloud type (shallow or deep; stratiform or convective). Once all vortices were documented, conventional meteorological data and analyses were consulted. One objective of the study was to determine whether satellite imagery could be used to estimate the central pressure of the cyclones accompanying the mesoscale vortices. Other objectives were to determine if there were significant differences in (1) the mesoscale cloud structure or (2) the large-scale environment of vortices which remained insignificant versus those that developed into polar lows. Results indicate that the deficit pressure of the polar vortex could be estimated from satellite imagery and that there were recognizable differences between developing and non-developing vortices. Only a few cloud configurations accompanied polar lows, whereas the occurrence of certain other configurations at early stages in the vortex existence indicated that these vortices would remain insignificant. The synoptic-scale environment appeared to play a considerable role in determining which incipient vortices continued to develop. Moderate baroclinicity (horizontal temperature gradients and vertical wind shear), relatively weak winds, large lapse rates, and favorable vorticity advections accompanied developing polar lows. Non-developing vortices had unfavorable vorticity advections. Of these, some vortices were able to grow initially to moderate disturbances which remained steady thereafter. The apparent difference between these and insignificant vortices was that the steady vortices were more baroclinic and had steeper lapse rates. DOI: 10.1111/j.1600-0870.1985.tb00276.x