太平洋海温三极子对中国东北地区春玉米气候产量的影响

Effect of Pacific SST tripole on climatic yield of spring maize in northeast China

利用1949—2018年玉米产量数据、NCEP再分析资料、帕尔默干旱指数、标准化降水蒸散指数、土壤含水量和SST等,分析了太平洋海温三极子对中国东北地区春玉米气候产量的影响。结果表明:东北地区春玉米气候产量与收获当年1—5月的太平洋海温三极子存在显著相关,太平洋海温三极子能够通过太平洋上空的遥相关型影响东北地区春玉米播种出苗期和全发育期的区域环流场,进而影响区域降水、土壤含水量、帕尔默干旱指数和标准化降水蒸散指数等与东北地区春玉米气候产量密切相关的因子。当太平洋海温三极子增强时,太平洋上空会形成类似Rossby波列结构的遥相关型,在东北地区高空产生负涡度异常,有利于上升气流的形成和降水的增加。太平洋海温三极子也有利于在低层形成从西北太平洋向东北地区的东南风异常,通过水汽传输进一步增强东北区域降水。

Based on maize yield data,NCEP re-analysis data,self-calibrating Palmer drought severity index(scPDSI),standardized precipitation-evapotranspiration index(SPEI),soil water content and sea surface temperature(SST)data,the effect of pacific SST tripole on climatic yield of spring maize in northeast China was analyzed.It was found that the climatic yield of spring maize in northeast China was significantly correlated with the Pacific SST tripole from January to May of the harvest year.The Pacific SST tripole could influence the regional circulation field during the seeding stage and the whole growing season of spring maize in northeast China through the teleconnection pattern over the Pacific,and then affect regional precipitation,soil moisture content,scPDSI,and SPEI,which are closely related to the climatic yield of spring maize in northeast China.When the Pacific SST tripole strengthens,a Rossby-wave-like teleconnection pattern will be formed over the Pacific,resulting in a negative vorticity anomaly in the upper air of northeast China,which is conducive to the formation of local updraft and the increase of precipitation.The Pacific SST tripole is also conducive to the formation of the southeast wind anomaly from the northwest Pacific to northeast China at the low level,which further enhances the precipitation in northeast China through water vapor transport.