前期热带太平洋、印度洋持续性海温异常事件对菲律宾低层大气环流的影响

Impacts of long lasting SST anomaly events in the tropical Pacific and Indian oceans on anomalous Philippine Sea anticyclone

利用NCEP/NCAR 的1951~2010 年逐月再分析资料和NOAA 气候诊断中心的1951~2010 年的海表温度扩展重建资料, 在诊断分析的基础上结合数值模拟试验探讨了前期秋季开始持续的热带海温异常事件对菲律宾低层大气环流的影响.结果表明： 1）相比于西南印度洋海温异常事件和北印度洋海温异常事件, 前期秋季印度洋上与9 月至次年6 月的菲律宾异常反气旋（PSAC）关系最为密切的是印度洋偶极子事件（IOD）; 2）在前期秋季单纯El Ni？o 事件发生时, 11 月至次年5 月在菲律宾海地区均表现出明显的异常反气旋性环流特征.在没有El Ni？o 事件影响时, 单纯正位相IOD 事件下从11 月到次年4 月菲律宾海地区依然表现出异常反气旋性环流特征, 但再分析资料表明其强度要较El Ni？o 情形下的偏弱;3）当正位相两事件伴随发生时, 两事件对El Ni？o 具有协同作用, 在该作用下菲律宾海地区的反气旋异常环流相对于单纯某种海温异常事件表现得更加强大, 且持续时间更长, 甚至到8 月仍表现出显著的反气旋环流特征.

Based on the NCEP/NCAR reanalysis data and the sea surface temperature （SST） data from the NOAA, theinfluence of SST anomalies （SSTAs） associated with the ENSO and IOD （Indian Ocean Dipole） events on low-levelanomalous anticyclone in the Philippine Sea （named PSAC） was investigated using diagnosis methods and simulationexperiments. The results are as follows. There is a more significant relationship between the IOD events in precedingautumn and the PSAC from winter to spring than that between other Indian SSTA events and PSAC. In a pure El Ni？oyear, there is a notable PSAC appearing over the Philippine Sea from November to the following April. Compared to theEl Ni？o events, the influence of pure positive IOD events on the PSAC is much weaker based on the reanalysis data andhas shorter lifecycle from November to the following April. In the co-occurring year of El Ni？o and IOD, the PSACtends to enhance and remain until the following August, which indicates that these SSTA events reinforce the PSACjointly.