MJO对我国天气气候影响的新事实
A New Look at Impacts of MJO on Weather and Climate in China
中文摘要：
在次季节时间尺度上，热带大气季节内振荡（MJO）是全球气候变率的首要模态。MJO不仅对热带天气气候产生直接影响，还能够通过传播和激发大气遥相关等方式对热带外地区产生重要影响，成为目前次季节—季节气候预测最重要的可预报性来源。MJO对于我国天气气候影响的探索由来已久，在很多方面有了显著进展，但仍需深入研究。首先对MJO影响我国天气气候的过往研究进行了回顾，并进一步利用新的观测资料诊断分析，发现了MJO对我国气候影响的一些新事实。初步结论包括：MJO对我国冬季降水的影响主要局限在江南—华南区域，而夏季扩展到南方和青藏高原地区；对冬季气温的影响较大，其范围覆盖了东北、华北以及西部广大区域，而夏季解释方差有所减小，其区域位于除了黄河流域以外的广大地区；在去掉高频噪音后，纯粹MJO信号对我国主要区域气温和降水低频变化的解释方差可接近30%；MJO对我国冬夏季温度降水的影响存在明显滞后效应，应在使用MJO信号进行我国气象要素预报时加以考虑。
中文关键词：
MJO，中国气候，降水，气温，影响
KeyWords：
MJO, climate in China, rainfall, surface air temperature, impact
Abstract：
Madden-Julian Oscillation (MJO) or more generally called tropical Intra-Seasonal Oscillation (ISO), dominates climate variability worldwide on the subseasonal timescale. It is well-known that MJO can impact weather and climate not only in
tropics, but also in extratropics through the propagation and excitation of atmospheric teleconnections, and is the most important predictability source in the subseasonal-to-seasonal prediction. A great many studies have focused on impacts of MJO on weather and climate in China in the past decades, and made a significant progress in different aspects. However, further deep understanding is still needed. This study firstly reviews previous studies of impacts of MJO on China weather and climate, and then shows the new results regarding such impacts of MJO, based on diagnoses of new observations, then gives preliminary conclusionsas followings:. the impacts of MJO on rainfall are mainly limited in the regions from south of Yangtze River to the South of China in winter, but are extended to the more southern and Tibetan Plateau areas in summer. It shows a significant influence of MJO on
winter temperature over the Northeast of China, the North of China, and most of the western China, while a relatively weakened impact on summer temperature over the large areas in China except for the Yellow River Basin. After removing high-frequency noise, pure MJO signal can explain about 30% variance of low-frequency surface air temperature and rainfall in China. Moreover, it is found that there is a delayed impact of MJO on temperature and rainfall in both winter and summer in China and it is need to be consideredin the future predictions and futher studies .
tropics, but also in extratropics through the propagation and excitation of atmospheric teleconnections, and is the most important predictability source in the subseasonal-to-seasonal prediction. A great many studies have focused on impacts of MJO on weather and climate in China in the past decades, and made a significant progress in different aspects. However, further deep understanding is still needed. This study firstly reviews previous studies of impacts of MJO on China weather and climate, and then shows the new results regarding such impacts of MJO, based on diagnoses of new observations, then gives preliminary conclusionsas followings:. the impacts of MJO on rainfall are mainly limited in the regions from south of Yangtze River to the South of China in winter, but are extended to the more southern and Tibetan Plateau areas in summer. It shows a significant influence of MJO on
winter temperature over the Northeast of China, the North of China, and most of the western China, while a relatively weakened impact on summer temperature over the large areas in China except for the Yellow River Basin. After removing high-frequency noise, pure MJO signal can explain about 30% variance of low-frequency surface air temperature and rainfall in China. Moreover, it is found that there is a delayed impact of MJO on temperature and rainfall in both winter and summer in China and it is need to be consideredin the future predictions and futher studies .