The significant relationship between the Arctic Oscillation (AO) in December and the January climate over South China
The significant relationship between the Arctic Oscillation (AO) in December and the January climate over South China
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DOI：
10.1007/s00376-010-0019-y
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发表时间：
2011-02
影响因子：
5.8
通讯作者：
Hui Yang
中科院分区：
文献类型：
--
作者：
Hui Yang
利用NCEP/NCAR再分析资料、中国气象局的中国降水和地面温度资料以及NOAA的北极涛动（AO）指数，研究了AO与中国降水和温度的关系。12月AO指数与华南1月降水量有较好的相关性，表明当12月AO指数为正（负）时，华南1月降水量增加（减少）。华南地区12月AO指数与1月地面温度也存在显著的负相关关系，表明当12月AO指数为正（负）时，华南地区1月温度下降（上升）。这种异常气候的发生与大气环流系统的异常有关。12月AO对1月环流异常影响较大。AO的正位相导致伊朗高原到青藏高原南侧副热带急流增强。其结果是在孟加拉湾附近形成一个加深的低压槽，不断向华南输送暖湿空气。1月的西伯利亚高压更强，并向东南方向延伸。导致1000百帕冷空气持续涌入华南地区，导致气温较低。与孟加拉湾槽共同作用，华南地区出现异常降水。对于12月AO的负相位，观察到相反的情况。
Using NCEP/NCAR reanalysis data, the China rainfall and surface temperature data of the China Meteorological Administration, and the Arctic Oscillation (AO) indices of NOAA, the author investigates relationships between the AO and the precipitation and temperature over China. There exists a good relationship between the AO index in December and the succeeding January precipitation over South China, indicating that when the December AO index is positive (negative), the January precipitation over South China increases (decreases). A remarkable negative correlation between the December AO index and the January surface temperature also exists over South China, indicating that when the December AO index is positive (negative), the January temperature over South China drops (rises). The occurrence of this anomalous climate is related to the anomalies of the atmospheric circulation systems. The December AO greatly influences circulation anomalies in January. A positive phase of the AO is found to lead to a stronger subtropical jet over the south side from the Iran Plateau to the Tibetan Plateau. Consequently, it results in a deepening pressure trough around the Bay of Bengal, which transports the warm and wet air to South China continuously. The Siberian High in January is stronger and extends farther southeastward. It results in continual cold air at 1000 hPa pouring into South China, inducing low temperature. Cooperating with the trough of the Bay of Bengal, anomalous precipitation occurs over South China. For the negative phase of the December AO, the opposite situation is observed.