山东省夏季降水与赤道中东太平洋前期冬季海温对应关系的年代际变化

Decadal Variation of the Relationship Between Summer Precipitation in Shandong Province and Previous Winter SST over the Equatorial Central and Eastern Pacific

基于NCEP再分析资料的月平均500 h Pa高度场、NOAA月平均海温资料和山东省121个测站逐月降水资料,对1961—2015年山东省夏季降水与赤道中东太平洋海温对应关系的年代际变化进行研究。结果表明,山东省夏季降水在1970年代中期以及1980年代末、1990年代初发生了明显的转变。其中,在1970年代中期以前,山东省夏季降水量为线性减少趋势,总量偏多,而在1990年代以后,无明显变化趋势。山东省夏季降水与赤道中东太平洋前期冬季海温的关系在转变前后有明显差异:在1970年代中期之前,二者为反位相关系;1990年代之后,二者转为同位相关系。此外滑动相关结果也显示,1990年代以前,山东省夏季降水与Ni1o3区前期冬季海温为负相关关系,1990年代之后,二者为正相关关系。进一步研究发现,山东省夏季降水与西太平洋副热带高压之间的相关关系也发生了年代际变化:在前一时期,山东省夏季降水偏多年份的水汽主要来自东亚夏季风的输送;在后一时期,山东省夏季降水偏多的年份水汽主要来自El Ni1o次年夏季副热带高压西侧偏南气流的输送。

Based on the monthly average 500 h Pa geopotential height field of NCEP reanalysis data,the monthly average sea surface temperature（SST） of NOAA reanalysis data and the monthly precipitation data at 121 meteorological stations in Shandong Province,the decadal variation characteristics of relationship between summer precipitation in Shandong Province and SST over the equatorial central and eastern Pacific were studied during 1961-2015. The results show that the summer precipitation in Shandong Province had distinct abrupt changes in the middle of the 1970 s and in the late of the 1980 s or the early of the 1990 s. The summer precipitation before the middle of the 1970 s in Shandong Province decreased significantly as a whole,while after the 1990 s it wasn＇t obvious change. The relationship between summer precipitation and previous winter SST over the equatorial central and eastern Pacific appeared an opposite phase before the middle of the 1970 s and same phase after the 1990 s. In addition,the moving correlation showed that there was a negative correlation before the 1990 s between summer precipitation and previous winter SST over the Ni1o3 region,while there was a significant positive correlation after the 1990 s. Moreover,the relationship between summer precipitation in Shandong Province and the intensity of western Pacific subtropical high（WPSH） also had decadal variation. In more summer precipitation years,the water vapor in Shandong Province mainly came from the transport of East Asian summer monsoon before the middle of the 1970 s,while that mainly came from the transport of WPSH in next year of El Nino after the 1990 s.