西沙海域海气相互作用下季节内振荡的年际变化特征

Now the intraseasonal oscillation (ISO) of the air-sea interaction has a good relationship with the global climate change and local extreme weather. Research shows that the ISO in the South China Sea (SCS) plays an important role in the climate in the Southern China. The interanual variability of the ISO in the SCS is modulated by large scale interannual variation from the Pacific (eg ENSO) and the Indian Ocean (eg Indian Ocean Dipole, IOD). Meanwhile, the SCS is strongly influenced by East Asian monsoon, thus the ISO shows distinct regional features. Because there were few studies carried out for the interannual variability ISO in the SCS, this project will study the oceanic and atmospheric responses of the ISO around the Xisha waters in different years, by using the Xisha observations, the SCS open cruise data and reanalysis data and numerical simulation. The SCS local air-sea environment is modulated by the interannual variations of ocean ISO and the SCS internal circulation, and the ananlysis of the related dynamic and thermodynamic mechanism.

目前海气相互作用下的季节内振荡与全球气候变化以及局地极端天气的发生有着密切的联系。研究表明南海季节内振荡对我国华南地区气候有着重要影响。从动力学和热力学机制上看，南海的ISO（Intra-Seasonal Oscillation）受大洋尺度ISO的调制作用，在年际尺度上主要有太平洋（如ENSO）和印度洋(如Indian Ocean Dipole，IOD)的年际变化。同时，南海位于季风东亚区，东亚季风环流的显著影响使得南海季节内振荡有具有鲜明的区域特征。由于前人针对南海季节内振荡的年际特征研究较少，本项目将通过西沙观测资料、南海北部航次资料、再分析数据结合数值模拟研究不同年份的西沙海域季节内振荡周期中海洋与大气环流环境响应情况，包括局地海气环境受到大洋ISO信号传播年际调制和南海内部环流反馈响应过程，分析其中动力热力学机制。

南海尤其是西沙海域的季节内振荡海气相互作用的年际变化下对我国华南地区气候有着重要影响。从动力学和热力学机制上看，南海的ISO（Intra-Seasonal Oscillation）受大洋尺度ISO的调制作用，在年际尺度上主要有太平洋和印度洋的年际变化。同时，南海位于季风东亚区，东亚季风环流的显著影响使得南海季节内振荡有具有鲜明的区域特征。本项目将揭示了南海准两周振荡和30-60天振荡两种主要信号在南海不同年份传播演变情况；研究了不同年份的春季西沙海域的海温除受局地暖涡影响外，大气季节内信号的调制作用并进一步讨论利用粤西海域高频地波雷达观测得到的表层海流资料不同信号特征，分析其中动力热力学机制。