乌拉尔山阻塞高压过程波流相互作用及其与极锋急流之间的关系研究

Urals blocking high has important impact on weather and climate in east Asia. In resent decades, establishment and decay of Urals blocking high becomes slow and rapid, respectively. The relationship between Urals blocking and eastern Asia winter monsoon has been increased, showing a more important impact of blocking high on weather and climate in winter and spring in east Asia. Thus it is necessary to explore character of wave-flow interaction and heat and momentum during blocking process by using the newest data. More important, it is essential to investigate the relationship between Urals blocking high and polar jet stream and its climate effect under a background of warm climate. By using datasets including station data, reanalysis data, and CMIP outputs and methodologies including statistics, dynamical diagnose, and theoretical analysis, this program plans to compare and analyze character of wave-flow interaction and heat, momentum during blocking process in winter and spring in the Urals region, investigate the relation between blocking and westerly and polar jet, explore the dynamical relationship between Urals blocking high and climate in east Asia, and reveal its corresponding physical mechanism. Based on above results, physical conception model will be illustrated for the influence of Urals blocking high on climate in east Asia. Related works are not only good to deepen the understanding in physical process and dynamical mechanism of impact of Urals blocking high on climate in east Asia, but also beneficial for scientific basis and reference for relationship between Urals blocking high and polar jet and climate change in winter and spring in east Asia.

乌拉尔山阻塞高压对于东亚天气气候有重要影响。近几十年，乌拉尔山阻高的形成过程变慢、而崩溃过程加快，与东亚冬季风的联系更加密切，这种变化可能与其动力学过程发生了变化有关。但现有关于乌拉尔山阻高过程动力学的研究多关注于其动力特征而较少涉及其热力过程；气候变暖背景下，乌拉尔山阻高与极锋急流相互关系的变化特征也亟需研究。本项目拟利用地面台站和再分析资料并结合CMIP模式输出，通过资料统计、动力诊断和理论分析等方法，系统地对比研究冬春季乌拉尔山阻高过程中波流相互作用和热、动力特征，探究阻高和西风气流尤其是与极锋急流之间的关系及变化，探析冬春季乌拉尔山阻高与东亚气候的动力关系，揭示其物理机制；在此基础上，给出乌拉尔山阻高影响东亚冬春季气候的物理概念模型。相关工作的开展，不仅可以加深对于阻塞高压影响东亚气候的物理过程和动力机制及其与急流的相互关系的理解，还可为东亚冬春季气候的未来变化提供科学依据和参考。

目前在阻塞高压的定义、定量化表征、统计特征及其对东亚天气气候的影响的方面已经发表了大量的研究，过去的关于阻塞高压动力机制的研究主要集中在动力学方面，而较少关注阻高形成到崩溃分阶段的热力过程；且较多研究集中于阻塞高压的形成和维持上。而实际上，乌拉尔山阻塞高压崩溃过程对于东亚地区冬春季天气气候有着非常重要的作用，崩溃过程往往伴随大范围的环流调整，冷空气也随之向南爆发。尤其是，乌拉尔山阻高在2000–2013年的持续时间相对于1979–1999年变长，其建立过程变慢、崩溃过程变快，阻高过程相应的动力和热力过程肯定也出现了变化。针对以上研究背景，本项目拟研究以下内容：冬、春季在乌拉尔山地区形成的阻高，其生成到崩溃过程中，西风气流和阻高之间存在着怎样的相互作用，在基本气流和阻高相互作用的各阶段，其热、动力通量如何交换，由此产生的热、动力强迫又如何相互影响；此外，乌山阻高和极锋急流的关系如何变化，对于东亚冬春季气候的影响有无变化。项目完成了研究目标，研究结果揭示了乌拉尔山阻高从形成到崩溃过程中波流相互作用和热动力特征，发现准定常波和瞬变波波动对于阻高过程均具有重要作用，得到了乌拉尔山阻高与急流之间关系及其对于东亚气候的动力影响机制，评估了CMIP6模式对于欧亚阻高频次及其与急流之间关系的模拟能力，并对未来阻高和急流之间关系的可能变化给出了预估。项目支持下共发表论文9篇，其中SCI论文4篇，中文核心论文5篇，获得软件著作权1项，在中高纬度大尺度天气动力学方向培养博士研究生1名，硕士研究生3名。