南印度洋热带气旋生成频数气候变率对海温异常模响应的研究

基于1980—2014年的哈德莱中心海冰及海温的月平均SST资料,美国联合台风警报中心(JTWC)的best-track资料以及NCEP/NCAR再分析月平均资料,利用广义平衡反馈方法(GEFA)研究南印度洋热带气旋(TC)生成频数对海表温度异常的响应特征。研究表明:(1)南印度TC生成频数对北太平洋第一模态(NP1)和热带大西洋第二模态(TA2)有显著响应,分别通过了置信度为99%和96%的Monte-Carlo检验,对应的响应振幅分别为0.67和0.49。(2)局地环境要素对关键SSTA模的GEFA响应结果显示:当NP1出现类似于太平洋年代际振荡(PDO)的正位相时,850 h Pa相对涡度在15°S附近的印度洋海域上都有一个自西向东的显著正响应带,垂直风切变在马达加斯加以东的大部分海域都表现为显著的负响应,600 h Pa相对湿度在马达加斯加以东的部分海域表现为显著的正响应;当TA2对应的时间系数为正异常时,850 h Pa相对涡度和600 h Pa相对湿度在澳大利亚的西北部印度洋海域表现为显著的正响应,垂直风切变在澳大利亚的西北部印度洋海域表现为显著的负响应。

Study on the response of sea surface temperature anomaly model of the tropical cyclone frequency climatic variability in the southern Indian Ocean

Based on the monthly mean SST data of Hadley Center of sea ice and SST in 1980-2014, best-track data from the United States Joint Typhoon Warning Center (JTWC) and NCEP/NCAR reanalysis monthly mean data, by using the generalized equilibrium feedback assessment (GEFA) obtained the response factor and response amplitude of South Indian Ocean tropical cyclone frequency to significant basin. The main conclusions are as follows:(1) The frequency of tropical cyclone in southern Indian Ocean has a significant response to NP1 and TA2, respectively, through the 99% and 96% Monte-Carlo test, corresponding response amplitudes were 0.67 and 0.49.(2) The GEFA response results of the local environmental factors on the critical SSTA model are shown:when NP1 appears similar to the positive phase of Pacific Decadal Oscillation(PDO), 850 hPa relative vorticity at 15°S near India Ocean has a significant positive response from the west to the east zone, vertical wind shear showed significant negative response in most of the sea area in the east of Madagascar, 600 hPa relative humidity showed a significant positive response in some sea areas in the east of Madagascar; when TA2 corresponds to a positive time anomaly, 850 hPa relative vorticity and 600 hPa relative humidity showed a significant positive response in the Australia''s Northwest Indian Ocean, vertical wind shear is a significant negative response in Australia''s Northwest Indian Ocean area.