正压大气中基态定常波对强迫响应的影响

THE INFLUENCE OF STATIONARY WAVES ON FORCED RESPONSE IN BARO-TROPIC ATMOSPHERE

本文利用正压涡度方程模式研究了热带不同经度位置异常强迫激发的中纬响应类型与北半球冬季基本气流定常波结构的关系。发现对热带印度洋和太平洋的大部分地区,中纬的响应类型主要由基态定常波的结构决定,并且基态定常波通过向扰动转换动能维持了中纬的响应。通过这些结果解释了GCM研究中发现的中综异常响应类型对El Nino成熟期海表面温度异常位置变化的不敏感性。此外还讨论了观测和GCM中出现的热带印度洋——太平洋地区低频尺度上的纬向偶极强迫源对GCM响应结果的作用。

In this paper, a barotropic vorticity equation model is used to investigate the relationship between midlatitude response of tropic forcing from different longitudinal positions and Northern winter stationary waves of basic flow. The results indicate that for the tropic forcing over most area of Indian Ocean and Pacific the midlatitude response patterns are determined mainly by the structure of the basic flow and are supported by the kinetic energy conversion of basic flow to perturbation. These results could interpret the finding that the structure of the GCM's midlatitude response is insensitive to the longitudinal position of the SST anomaly forcing during El Nino episode. Moreover, the roles of zonally oriented low frequency dipole convective anomaly forcing appeared in observation and GCM simulaton on GCM midlatitude response are also discussed.