区域海气耦合模式模拟的2003年东亚夏季风季节内振荡

评估了一个区域海气耦合模式(由区域环境系统集成模式RIEMS和普林斯顿海洋模式POM组成)对2003年东亚夏季风季节内振荡(ISO)的模拟性能。通过与观测海温驱动单独大气模式结果的比较,分析了海气耦合过程对东亚夏季大气ISO模拟性能的影响。结果表明:耦合模式能够模拟出2003年中国东部地区夏季降水的气候态分布,模拟的中国东部尤其是江淮地区大气ISO活动较单独大气模式更为显著。同时,耦合模式能够较好地再现大气ISO经向上北传的传播特征,模拟的江淮流域降水处于活跃和中断期时西北太平洋地区低频降水和环流异常在强度和空间分布上较单独大气模式都更为合理。相比于单独大气模式,耦合模式对大气ISO模拟的改善,一方面与其对气候态西北太平洋副热带高压和相关对流层底层风场模拟的改善有关,另一方面与其包含海气相互作用,因而对低频降水与海温和水汽辐合位相关系模拟的改善有关。

Simulation of Intraseasonal Oscillation of East Asian Summer Monsoon in 2003 by a Regional Air-Sea Coupled Model

The performance of a regional air-sea coupled model, comprising the Regional Integrated Environment Model System (RIEMS) and the Princeton Ocean Model (POM), in simulating the intraseasonal oscillation (ISO) of East Asian Summer Monsoon in 2003 was evaluated by comparison of the observations and results of an uncoupled model. The results showed that the regional air-sea coupled model reproduced well the spatial pattern of summer mean precipitation in 2003 and simulated a stronger ISO than the uncoupled RIEMS across eastern China, especially over the Yangtze-Huaihe Valley. Meanwhile, the coupled model showed high skill in simulating the meridional northward propagation of ISO over East Asia, and presenting the distribution and intensity of the intraseasonal precipitation and circulation anomalies over Northwest Pacific during the driest and wettest phases of the Yangtze-Huaihe Valley more realistically compared to the uncoupled RIEMS. Further analysis indicated that improvements in the simulation of ISO by the coupled model were due to better simulation of the western North Pacific Subtropical High and realistic phase relationship between the intraseasonal convection and the underlying sea surface temperature resulting from air-sea coupling.