伴随IOD型和独立型ENSO对山东气候年际变化的影响

The impacts of ENSO for accompanied with IOD type and isolated type on the interannual climate variability in Shandong

使用1951年以来66 a的观测和再分析资料,通过合成分析的方法对比分析了厄尔尼诺/拉尼娜(El Nio/La Nia)伴随正/负印度洋偶极子(positive/negative Indian Ocean Dipole,pIOD/nIOD)发生年或独立发生年山东夏、秋季气温和降水的年际变化特征,结果表明,伴随IOD型和独立型El Nio/La Nia对山东夏、秋季气温和降水的影响在强度、范围、正负位相、空间型态上存在很大的差异。在气温方面,El Nio在p IOD的调制作用下对山东南部地区夏季气温年际变化的影响加强;El Nio与p IOD伴随发生时,山东秋季气温较常年偏高,而独立发生时气温则偏低,呈反位相变化;La Nia与n IOD伴随发生年夏季鲁西北气温较常年偏低,La Nia独立发生年夏季半岛东部气温较常年偏高,气温异常呈反位相变化;nIOD对La Nia的调制促进作用有利于山东秋季气温较常年异常偏高;850 h Pa气温异常与山东表面气温异常有很强的正相关关系。在降水方面,El Nio在pIOD的调制作用下容易引起山东北部地区夏季降水偏少,但会削弱其对山东中部地区秋季降水负异常的影响;La Nia在n IOD的调制作用下山东境内降水都较常年偏多,但降水异常地域分布非常不均,鲁西北降水较常年显著偏多;独立型La Nia更易引起鲁西北西部、鲁中、鲁南大部分地区夏季降水偏少。850 h Pa环流异常配合温度场异常对山东夏、秋季降水异常分布有一定的影响。

Based on the observation and reanalysis datasets since 1951,the interannual variability of air temperature and precipitation in Shandong under the influence of El Nio/La Nia-Southern Oscillation（ ENSO） with（ accompanied type） or without（ isolated type） Indian Ocean Dipole（ IOD） are conductedthrough the composite analysis. It is discovered that there are distinct differences on the effect intensity,extent,phase and spatial pattern of interannual variability between the accompanied and isolated type of ENSO： for the air temperature,with the reinforce of positive IOD（ p IOD）,El Nio has more notable effect on the air temperature anomalies over the south of Shandong in summer; when El Nio occurs with p IOD,the air temperature in Shandong is higher than normal in autumn,while it is lower when El Nio occurs only,which varies out of phase; when La Nia appears with negative IOD（ n IOD）,the air temperature over the northwest of Shandong is lower than normal,while it is higher over the east of Shandong Peninsula when La Nia appears only,which varies out of phase too; as a joint influence of La Nia and n IOD,the air temperature over Shandong is higher than normal in autumn; a close correlation exists between the air temperature anomalies at surface and 850 h Pa over Shandong during the summer and autumn of El Nio/La Nia. As for the precipitation,under the influence of p IOD,El Nio tends to reduce the precipitation of the north Shandong in summer,but weakens its influence on the negative precipitation anomalies in the middle of Shandong. La Nia occurring with n IOD has a stronger effect on the interannual variability of summer precipitation in Shandong; the precipitation displays significant inhomogenous distribution accompanying with significant positive anomalies in the northwest of Shandong;for the isolated La Nia,the summer precipitation is less than the climatology in the northwest,middle and south of Shandong; the circulation anomalies accompanied with the air temperature anomalies at 850 h Pa play a role in the precipitation anomalies over Shandong in summer and autumn.