印度洋海温异常对西太平洋副热带高压的影响——大气中的两级热力适应

IMPACTS OF THE SEA SURFACE TEMPERATURE ANOMALY IN THE INDIAN OCEAN ON THE SUBTROPICAL ANTICYCLONE OVER THE WESTERN PACIFIC——TWO-STAGE THERMAL ADAPTATION IN THE ATMOSPHERE

中文关键词:  两级热力适应  过流  降水异常  副高异常

英文关键词:Two-stage thermal adaptation  Overshooting  Precipitation anomaly  Subtropical anticyclone anomaly

中文摘要:

      利用热力适应理论讨论了印度洋海温异常影响中国天气和西太平洋副热带高压异常的物理机制。结果表明:通过第一级热力适应,印度洋上的海温异常形成低层气旋式环流,并在其东侧的偏南气流中产生对流性降水;然后通过第二级热力适应,在500hPa上导致西太平洋副热带高压加强西伸、200hPa上南亚高压异常增强。从而证明两级热力适应是导致印度洋海温异常影响中国天气气候异常的重要物理机制。

英文摘要:

      The thermal adaptation theory is used to investigate the impacts of the sea surface temperature (SST) anomaly in the Indian Ocean on the wea ther over southern China and the subtropical anticyclone over the western Pacific Ocean. Results show that through the first stage of the atmospheric thermal ad aptation to the SST anomaly in the Indian Ocean, the in situ anomalous cyclonic circulation in the lower layers of the troposphere is formed, and deep convective precipitation to its east is generated due to the development of southerlies. Then through the second stage of the atmospheric thermal adaptation to the latent heating resulting from the precipitation condensation, anomalous anticyclone circulation is produced at 500 hPa over the western Pacific and at 200 hPa over South Asia. It is therefore concluded that the two-stage thermal adaptation is an important mechanism that links the occurrence of the anomalous subtropical a nticyclones and climate over the eastern Asian monsoon region to the SST anomaly in the Indian Ocean.