地球系统模式FIO-ESM对2016-2017年La Ni(n)a事件及其对中国近海地区影响的预测

摘要

Recent observations have shown that the SST anomalies in the central and the eastern Tropical Pacific Ocean are slightly lower than the La Ni(n)a threshold (-0.5℃),but both the atmospheric and oceanic states cannot fully support the turning to weak La Ni(n)a.In the present paper,assimilation of the climate models from 1 January 1992 to 31 October 2016 is carried out by using the First Institute of Oceanography-Earth System Model (FIO-ESM) and the short-term climate assimilation and forecasting system established based on the Ensemble Adjusted Kalman Filter (EAKF) assimilation scheme,showing that the assimilation system can provide a good initial field for prediction.Afterwards,the states of the 2016-2017 La Ni(n)a event and the anomalies of the air temperature and the precipitation in the coastal regions of China are predicted for the future 6 months.The predicted results indicate that the surface water of the Tropical Pacific Ocean will continue to cool down by the end of 2016,and the SST anomaly in the Ni(n)o3.4 area will still be slightly lower than -0.5 ℃,indicating that there will be a weak La Ni(n)a in 2016-2017.It is also shown that the SST in the eastern Tropical Pacific Ocean will continuously drop down in spring of 2017,suggesting that the 2016-2017 La Ni(n)a be lasted longer.The predicted results also show that air temperature anomaly which shows higher in the north and lower in the south occurs in the coastal regions of China from winter of 2016 to spring of 2017.In the southern region of China a negative anomaly of precipitation is present.The Extreme weather and climate anomalies associated with La Ni(n)a can cause a great influence on the coastal regions of China,but the influence caused by the 2016-2017 La Ni(n)a would be relatively weak in general.%最近的观测表明赤道太平洋中部及东部的水温略低于拉尼娜事件的阈值,但大气与海洋的状态还不足以完全支持转为弱拉尼娜现象.本研究基于地球系统模式FIO-ESM和集合调整卡尔曼滤波同化方案建立的短期气候同化和预测系统,进行了1992-01-01-2016-10-31的模式同化,结果表明同化系统能够为预测提供较好的初始场.随后对2016-2017年拉尼娜事件的状态以及中国近海地区气温和降水异常进行了未来6个月的预测,结果表明赤道太平洋会在2016年年底继续降温,Ni(n)o3.4区海温异常将持续略低于拉尼娜事件的阈值-0.5 ℃,说明2016-2017年为弱拉尼娜事件,2017年春季东太平洋继续降温,表明此次拉尼娜事件可能会持续较长时间.预测结果同时也表明2016年冬季至2017年春季中国近海地区存在着北高南低的气温异常分布,中国南部地区降水存在负异常.拉尼娜带来的极端天气与气候异常会对中国沿岸地区带来巨大影响,但总体来说2016-2017年拉尼娜事件对中国的影响相对较弱.