近20年来青藏高原低涡的研究进展

The Research Progress of the Tibetan Plateau Vortex in Recent Twenty Years

青藏高原低涡是青藏高原地区特有的产物,是夏季高原上的主要降水系统,而东移出高原的低涡,又往往引发青藏高原下游地区大范围的灾害性天气过程。对20世纪90年代以来,青藏高原气象学研究领域中有关高原低涡系统的若干进展做了简要综述,初步总结了各类研究涉及的重要问题及主要成果,在此基础上提出了目前高原低涡研究存在的主要问题和需要加强的几个研究方向,分别是:(1)高原地区的资料丰富与完整程度依然不足,有必要进行各种加密观测试验和大规模科学考察试验来获取更全面的资料。同时进一步加强资料的分析与综合应用,会对高原低涡天气气候与活动特征有更深入的认识;(2)在高原低涡生成与发展的研究方面,目前明确了低涡作为青藏高原特殊的天气系统,高原的动力和热力作用对它的产生、发展以及移动的影响十分显著,但是不同个例以及同一个例的不同阶段,高原的动力和热力作用有何区别,影响是否具有普遍性等问题并未圆满回答,还需继续深入研究;(3)高原低涡并非一独立存在的系统,其自身的发展变化以及东移过程也受诸多其他系统的影响,目前对高原低涡与高原500hPa切变线、西南低涡等其他系统相互作用有了一定的研究,但多数仅讨论两系统之间的外部关系与相互影响,多系统相互作用的机制问题也需要给予一定的重视;(4)不能忽略有些在高原上强烈发展但消亡而并未移出高原的低涡系统,这些高原低涡也可能通过波动传播的机制,诱发下游的天气变化;(5)理论研究是高原低涡研究的难点,但对于提高对低涡发生发展的认识至关重要,也有助于提升对青藏高原及其周边地区天气预报的能力;(6)了解模式在高原地区的局限性。同时,也应该利用卫星、雷达和加密观测资料进行同化模拟试验,提高模拟效果,用好数值模式这个有用的分析研究工具。

Tibetan Plateau vortex (TPV) is a unique product in the region of the Tibetan Plateau, and it is the main precipitation system in summer on the plateau. The eastward vortex moving out of the plateau is always giving rise to a large-scale severe weather process in the downstream area of the Tibetan Plateau. This study has given a brief overview of the research on TPV since 1990s, and has summarized the major achievements made on the basis of the TPV. Furthermore, it points out several research directions which should be put more emphasis on. They are (1) the data is still very inadequate in the region of the Tibetan Plateau, so it is very necessary to organize large-scale scientific observations to obtain more comprehensive data. And this will help deepen our understanding of the TPV. (2) It's believed that the thermal and dynamic effects of the Tibetan Plateau will obviously affect the generation, developing and moving stage of TPV which is a unique system of the Tibetan Plateau, but we are still not clear about the differences between the thermal and dynamic effects and we cannot tell which effect is more important in different stages of TPV. (3) TPV does not exist alone, for its own development and the eastward moving is also affected by many other systems. We now know some basic results of interactions between TPV and southwest vortex, but most of the discussions are limited to the two systems, and multi-system interaction mechanism also needs to be given some attention to. (4) We cannot ignore some of the TPVs which are strongly developed but not moving out of the plateau. However, these TPV’s fluctuations may also spread through the mechanism to induce downstream changes in the weather. (5) Theoretical research is a great challenge for understanding of TPV, which also helps to improve weather forecasts ability on the Tibetan Plateau and its surrounding areas. (6) We need to understand the limitation of numerical models in the plateau region. At the same time, satellite, radar and encryption observational data should be assimilated to improve simulation results.