21st Conf. on Severe Local Storms and 19th Conf. on Weather Analysis and Forecasting/15th Conf. on Numerical Weather Prediction

Monday, 12 August 2002
A preliminary comparison between convectively generated mesoscale vortices in the United States and in China
Jason C. Knievel, NCAR, Boulder, CO
Over the last few decades, there has developed in the published literature two distinct bodies of work on convectively generated mesoscale vortices. One is on vortices in the central United States that are often called mesoscale convective vortices (MCVs). The other is on vortices in China, some of which are called southwest vortices, and others, plateau vortices. Apart from a handful of exceptions, the two bodies of work have remained separate, despite obvious similarities in their subjects and the potential fruits of integrating the research efforts. The language barrier between many eastern and western scientists explains some of the problem. However, even the small, but significant, fraction of English articles on Chinese vortices has largely gone unacknowledged in papers written on MCVs.

In this paper the author presents a brief overview of the most important ways in which the population of convectively generated mesoscale vortices in the central United States and the population in China may be similar to, and different from, one another. Perhaps the comparison will stimulate more research into the similarities and differences.

MCVs and Chinese vortices clearly have much in common, but whether or not where they form is the only difference between them remains an open question. Vortices in both populations appear to be driven, directly or indirectly, by heating in moist convection. Both populations also display seasonal dependences. Perhaps most important for forecasting severe weather, mesoscale vortices in both nations seem to help organize, sustain, and generate large masses of cumulonimbi. Chinese vortices, in particular, have been linked for years to the devastating floods that plague the lowlands east of the Tibetan Plateau.

On the other hand, there are potential differences between the two populations of vortices. For example, Chinese vortices may depend on topography and pre-existing synoptic boundaries in ways that MCVs in the central United States do not. Vortices in the United States and in China may also play quite different roles in influencing the larger-scale synoptic and planetary circulations in which they develop.

In the end, so little is known about convectively generated mesoscale vortices in the United States and China that a more integrated exploration of the two populations should very quickly advance our global understanding of such vortices.

Supplementary URL: